Monday, November 30, 2009

ADXL345 accelerometer breakout board + Arduino and Processing

Some time ago I've purchased an ADXL345 accelerometer breakout board from SparkFun.com. After some searching and datasheeting (that's an awful term, I know :D), I've finally came up with code, which will allow me to talk to the accelerometer using my Arduino and even pass the data on, to Processing (it's a fun language, covered in my previous post)



In this post I will cover the setup for the communication procedure between the ADXL345 and the Arduino and then, between the Arduino and Processing (ie your PC). All the sources are at the bottom of the post, as usual. (Code is now updated for Arduino 1.0.4)


To tell you the truth, I don't know which you should do first, code the Arduino or hook up the ADXL (probably code first), but my fingers were itchy, so I hooked up the ADXL to the Arduino first:

Connecting ADXL345 breakout board and Arduino for I2C communication

Here's how it actually looks in life (click the pics for larger image)

ADXL345 and Arduino

ADXL345 wiring on breadboard

Arduino wiring for ADXL345

Now, after we have everything plugged in nicely, we may start writing the code for getting the acceleration values from the sensor. You might want to have the ADXL345 Datasheet handy while you code.

There are two ways to talk to the sensor, SPI and I2C protocols. I've chose the I2C (the schematics above are for I2C communication) because it is easier to wire for, and easier to code - the downside, they say, is that I2C is slower.

The Arduino Wire library provides a sort-of-easy way to interact with components that implement the I2C communication protocol. I wish I could say it's usage is straightforward, but it is not quite so. There are few catches! Though, if you're aware of them, the library should be easy to use.

Open page 10 in the datasheet, this page explains how to talk to the device using I2C protocol. When using I2C protocol there are two ways (yes, again two ways) to wire the ADXL345, each way gives it a different device address (so that may prevent address collision). You can see, that the wiring I chose, defines the device address as 0x53, the datasheet also says that this translates to 0xA6 address for write and 0xA7 address for read (because the base device address is 7-bit + 1 read/write bit). Ignore the read and write addresses as the Wire library takes care of this for us (catch).
Now, at the bottom of page 10 in datasheet, you see a diagram of how reads and writes should be performed. We'll start with the writes because:
  1. It's what we do first in the code
  2. Surprisingly, it's easier to do
The diagram shows that in order to perform a write to a register on a device, we need to go through the following steps:
  1. Initiate transmission to device (using write address*)
  2. Write the address of the register we want to write
  3. Write the data we want to write to the register
  4. Finish transmission
* We only use the base address of the device (0x53) because the read/write bit is handled by the Wire library.
** You will also note that there are 'ack' signals coming from the device, those are too, handled by the library

Looks pretty logical, and here's a function that will write a value to a certain register on a specified device (you'll need to add #include <Wire.h> to the top of your program to use the Wire library):

void writeTo(int device, byte address, byte val) {
   Wire.beginTransmission(device); //start transmission to device 
   Wire.write(address);        // send register address
   Wire.write(val);        // send value to write
   Wire.endTransmission(); //end transmission
}
So, let's say we want to write the value 8 to register 0x2D on device 0x53 (true story :D), we'll use this function like that:

writeTo(0x53, 0x2D, 8);

Ok, that was easy. The reading function is a bit longer, but uses similar concepts, so it's not going to be hard to follow. This time we want to perform a multiple-byte reading (as opposed to single byte writing we did in the writeTo() function). We need to read 6 bytes of data from the sensor (2 bytes for each axis), because, as the datasheet suggests, we don't want one axis value to change while we're reading another axis' values.

Lets look at that communication diagram on page 10 of the datasheet again. The steps we are to follow, in order to perform a multi-byte reading, are:
  1. Initiate transmission to device (using write address*)
  2. Write the address of the register we want to start** reading from
  3. Initiate transmission to device, again! (using read address*)
  4. Read bytes one after another
  5. Finish transmission

* Again, we only use the base address of the device (0x53) because the read/write bit is handled by the Wire library.
** When we're doing multiple bytes read (or write) we provide the start address - for example 0x15 - and the number of bytes we want to read - for example 4. That way we'll read values of registers 0x15, 0x16, 0x17, 0x18

So, let's see the read function:
void readFrom(int device, byte address, int num, byte buff[]) {
  Wire.beginTransmission(device); //start transmission to device 
  Wire.write(address);        //sends address to read from
  Wire.endTransmission(); //end transmission
  
  Wire.beginTransmission(device); //start transmission to device (initiate again)
  Wire.requestFrom(device, num);    // request 6 bytes from device
  
  int i = 0;
  while(Wire.available())    //device may send less than requested (abnormal)
  { 
    buff[i] = Wire.read(); // receive a byte
    i++;
  }
  Wire.endTransmission(); //end transmission
}
The new elements in this function are

  • Wire.requestFrom(device, num) - requests num number of bytes from device. The reading will start from the register passed in the Wire.write() call.
  • Wire.available() - returns true if there's something to read from the device
  • Wire.read() - reads one byte from the device
Essentially, this function performs the reading steps listed above. One thing to note, the result is saved in the buff array, and not returned by the function. So you must pass an array to the function and it has to be long enough to hold the data.

Whew! Ok, we have the read and write functions set. We're ready to write a program that will talk to the sensor (finally).

#include <Wire.h>
#define DEVICE (0x53)    //ADXL345 device address
#define TO_READ (6)        //num of bytes we are going to read each time (two bytes for each axis)

byte buff[TO_READ] ;    //6 bytes buffer for saving data read from the device
char str[512];                      //string buffer to transform data before sending it to the serial port

void setup()
{
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
  
  //Turning on the ADXL345
  writeTo(DEVICE, 0x2D, 0);      
  writeTo(DEVICE, 0x2D, 16);
  writeTo(DEVICE, 0x2D, 8);
}



Most of the code is pretty self-explanatory, so I'll explain only the code after the //Turning on the ADXL345 comment.
As you can see we are writing three different values to register 0x2D. 0x2D is the Power Control register of the ADXL345 (see datasheet). We first reset the power control register, then put the sensor in standby mode, and last we are putting it in to measure mode. We're doing the writes one after another because that's what the datasheet recommends. We could simply do the last write also. If you don't turn on the fourth bit on (writeTo(DEVICE, 0x2D, 8)) the sensor will be in sleep mode, and will give zero readings!!

And now, finally, the reading loop:

void loop()
{
  int regAddress = 0x32;    //first axis-acceleration-data register on the ADXL345
  int x, y, z;
  
  readFrom(DEVICE, regAddress, TO_READ, buff); //read the acceleration data from the ADXL345
  
   //each axis reading comes in 10 bit resolution, ie 2 bytes.  Least Significat Byte first!!
   //thus we are converting both bytes in to one int
  x = (((int)buff[1]) << 8) | buff[0];   
  y = (((int)buff[3])<< 8) | buff[2];
  z = (((int)buff[5]) << 8) | buff[4];
  
  //we send the x y z values as a string to the serial port
  sprintf(str, "%d %d %d", x, y, z);  
  Serial.print(str);
  Serial.write(10);
  
  //It appears that delay is needed in order not to clog the port
  delay(15);
}

Let's start from the beginning. The regAddress variable represents the register we want to start reading from (registers 0x32 - 0x37 are acceleration data registers, page 18 in the datasheet). We're defining the ints (x,y,z) which we'll use later, to send the data through serial port to Processing.
Next we're performing a readFrom function call, we pass our device's address, the register address to start reading from , the number of bytes to read and the buffer in which to save the data.
Now comes the tricky part - convert the data received from 2 bytes in to one int. Each axis' pair of bytes are manipulated, in order to create an int from two bytes using C bitwise operators (see here and here for more info on bitwise operators in C).
Afterward we're using the sprintf() function to turn the integers we have in to one string. And then we send that string to the serial port, terminating it with end-of-line character. The delay in the end is not strictly necessary, but it gave me better performance that way.

That's it! Below is a link to the sources - it also contains a matching Processing application to read the data and manipulate a model on the screen accordingly.

The next step is writing an actual 3D game for this thing, I'll probably do it using Microsoft's XNA studio, which appears to be pretty awesome. Stay tuned. Questions and comments are of course welcomed.

Source code files
Old sources (for before 1.0.4)

236 comments:

  1. hi,
    just tested your setup, worked at first try!
    thx a lot

    ReplyDelete
  2. hi, may i ask some questions?

    i'll follow these step to make my arduion with adxl 345.

    Sometimes it always return 0.

    Could you tell me why must it be this way?

    ReplyDelete
  3. A reason I can think of, is that you don't take your ADXL out of sleep mode (it's in sleep by default). In the code pieces I provide above look at the one with the "void setup()" function. The writeTo's after the "//Turning on the ADXL" actually deal with that. Let me know if you can't work it out.

    ReplyDelete
  4. I used your arduino and processing code and it works great. In its resting state it outputs something like 256 in the z direction for 1g of gravity. Assuming it maxes out at 1023 for 10-bit resolution, that means right now it's measuring +-4g. How do I make it so that the ADXL345 is measuring in the +-16g range?

    ReplyDelete
  5. The readings in current settings will max around 511 and min around -511, because it's a signed value (one bit is reserved for positive/negative), ie the range is +-2g.
    According to the datasheet (page 17), to set it to full resolution, you should set bits 0,1 and 3 of register 0x31 to 1. Havn't tried it yet, but you're welcome to post your results :)

    ReplyDelete
  6. I set bits 0, 1, and 3 of register 0x31 to 1 and it seems to work. It's now outputting in signed 13 bit resolution with what appears to be a +-16g range. With resting 1g I get ~256 in the z direction (4096/16=256). A max reading should be +-4095 though it's hard to max it out at 16g by waving it around :p

    ReplyDelete
    Replies
    1. can you explain where in the code you have to set bits 0, 1 ,3 of register 0x31 to 11.

      is it simply you add to this part of the existing code?

      //Turning on the ADXL345
      writeTo(DEVICE, 0x2D, 0);
      writeTo(DEVICE, 0x2D, 16);
      writeTo(DEVICE, 0x2D, 8);
      // adding 1011 binary to 0x31 register??
      writeTo(DEVICE, 0x31, 11);

      thanks

      Delete
  7. It'll be hard to get 16g by waving, but it'll surely be fun watching someone else trying :D

    ReplyDelete
  8. Hi,

    I have an arduino mega and have tried uploading your code and I can't get it to work, i think it may be because the mega has dedicated I2C pins (labelled SCL and SDA) and therefore i should be using these rather than the analog inputs, but i have tried wiring to these and it still just returns a reading of 0 for each axis. Any ideas...?

    ReplyDelete
  9. Hi, i did the last post but have now got it working so never mind, I must have wired it up wrong on previous attempts because it does just work if you wire up to the SCL and SDA pins, i think you have to wire it up before uploading the code for it to work. Thanks for the code!

    ReplyDelete
  10. What a time-saver. Your posting of this code and explanations helped me come up to speed on this device without having to study the data sheet id detail. I've used I2C before and I have used the Arduino, but never the two together. Thanks so much for your time and generosity in posting this!!

    ReplyDelete
  11. Very welcome :) Glad it's helpful

    ReplyDelete
  12. Thanks for the time saver.
    If you want to decrease the code size by 25%, you can try this new loop(). It worked for me. It works because the CPU is little endian, just like an x86 CPU.

    #define DATAX0 0x32 //X-Axis Data 0
    void loop()
    {
    int axis[3] ; //6 bytes buffer for saving data read from the device

    //each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!
    //thus we are converting both bytes in to one int
    readFrom(DEVICE, DATAX0, sizeof(axis), (byte*)axis); //read the acceleration data from the ADXL345

    //we send the x y z values as a string to the serial port
    Serial.print(axis[0], DEC);
    Serial.print('\t');
    Serial.print(axis[1], DEC);
    Serial.print('\t');
    Serial.println(axis[2], DEC);
    }

    ReplyDelete
    Replies
    1. Hey thanks alot for posting this as I have been trying to get the the serial monitor to display x,y, and z accelerations seperately. I dont fully understand how to place your code into the existing code. If I could see your full code which displays the x,y, and z accelerations seperately, I would be tremendously greatful.
      my email is austincb90@gmail.com

      Delete
    2. What do you mean when you say "separately"? In the original code they're separated by spaces, and here they are separated by tabs. If you want to use this output instead of the original you put this:
      sprintf(str, "%d\t%d\t%d", x, y, z);
      instead of this:
      sprintf(str, "%d %d %d", x, y, z);

      Delete
  13. Thanx for the tip! Very elegant. To be frank though, in a recent project I did, I passed the bytes as-is to the PC, and converted them there. On the other hand this same conversion technique can be used on the PC as well :)

    ReplyDelete
  14. is it possible to run two of these guys over spi on a single arduino?

    ReplyDelete
  15. Hi,
    e
    Thanks for this tutorial.
    I tried your code and schematic, but no success :
    http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1268490789
    I always get 0 0 0 0.
    Do you have an idea?
    What do you mean looking at the wake up lines? I tried delays but...

    Thanks !

    tep

    ReplyDelete
  16. Have you tried connecting everything without the unit in the middle? Only the ADXL and the Arduino?

    I also answered you in the forum on the link you've post, lets continue the discussion there

    ReplyDelete
  17. @Alex: should be possible without a spi if you get different addresses for the two adxls, no?

    ReplyDelete
  18. when using your sketch I'm gettingthe following error when trying to compile the code.

    In function 'void loop()':
    error: 'sprintf' was not declared in this scop

    Any ideas as how to fix this issue?

    ReplyDelete
  19. I don't know why are you having problems with sprintf, but instead you could simply use Serial.print(x, DEC), and same for y and z (with spaces between them).

    ReplyDelete
  20. Wonderful! Thanks so much for the code.

    And if you've been trying different code, Googling, and looking over your schematic for the past two hours... check to make sure that you're plugged into ANALOG 4 and 5, not digital pins 4 and 5 on the Arduino. *palm->face*

    ReplyDelete
  21. Hi Euristic.
    I a new user. Now I using the Arduino Mega(ATmega1280) and Sensor ADXL345.
    I try to wire along diagram that you show above but change AnIn4 to SCL Pin on board, AnIn5 -> SDA Pin on board. And upload coding to Arduino. and Run coding on Processing. It doesn't work. Can you suggest me. How should I do next setp. Thank for you help.

    ReplyDelete
  22. Hi Anonymous.
    It's vice versa my friend. AnIn4 is SDA (data) and AnIn5 is SCL (clock). According to the Arduino Wire library page, on the Mega SDA is digital pin 20 and SCL is 21.
    Hope that helps :)

    ReplyDelete
  23. Hi Euristic, I'm Methin who just post last message to you. Thank for your reply.
    Yes, I wire SCL(ADXL345) to SCL(Arduino Mega), and wire SDA(ADXL345) to SDA(Arduino Meag). and I correct the COM Port in Processing code already. But It doesn't work.
    Do I need to modify code anymore?
    Thank you for your help. :)

    Ping

    ReplyDelete
  24. Could you please email me about it, or make a thread on the Arduino forums so we can continue this discussion there?

    ReplyDelete
  25. Hi, I just took your Processing code and modified it to do exactly the same thing with a Seeduino Mega and an MMA7260QT 3-Axis Accelerometer from Pololu. This accelerometer puts out an analogue voltave in the range 0 to 3.3 volts so I use the ADC on the Seeeduino Mega (equiv to the Arduino Mega) and convert to 3-axis "G" force measurements before passing it to the Processing code. It works just like yours.

    ReplyDelete
  26. You are a hero! Thank you kindly.

    ReplyDelete
  27. Just what I needed. Thanks for breaking it down.

    ReplyDelete
  28. Hi!
    I´m new to accelerometers so this is a really great start! I´m trying to do the same, but using adxl335. However I´ve a doubt migrating the processing code! In this line:

    r[0] = (float)(Integer.parseInt(s.substring(0, i = s.indexOf(" "))) +OFFSET_X)*HALF_PI/256;

    the value 256 comes from your accelerometer datasheet, isn´t it?
    Reading your code I also understood that you´re not using z axis data...Am I write? Why? Sorry for this newbie questions :)
    thanks!

    ReplyDelete
  29. @Eduardo
    Hi! the 256 number comes from me knowing that 1g will be measured by the adxl345 as 256. So i'll always get a number between 0-0.5PI on both axes.
    I'm not using the Z axis because I don't need it for that specific application (although I might've needed it if wanted to be able to turn the model upside down). Hope, this helped!

    ReplyDelete
  30. Ok ! thanks a lot for the answer and for introducing me to the accelerometers! btw, It would be great if you could make an "hello world" example to the accelerometer using the 3 axis :)
    Best regards
    Eduardo

    ReplyDelete
  31. Hello!
    I am new to the area of the microcontroller, I will go into this field, I use adxl345 and AT90CAN128 (no Ardiuno), and I want to know what is wire.h and where can I download it?
    Many thanks for any help
    Simo

    ReplyDelete
  32. Wire.h is a C++ header file, for the Wire.cpp file - which is the Arduino Wire library. It comes with the Arduino IDE. You'll need both files to use the library, and I'm pretty sure you'll need an Arduino also

    ReplyDelete
  33. but there is a possibility my microcontroller (AT90CAN128) and your code to get up and running, without having to get an Arduino need?
    thank you for your attention Euristic
    Simo

    ReplyDelete
  34. @Simo
    I'm not sure, because it was written for the Arduino. Don't know if it's possible to just port it to another platform...

    ReplyDelete
  35. HI, may i ask some questions?

    What is mean 8bit data in buffer?

    example)
    buffer[0] = 0x00 0xfc 0x00 0x01 0x03 0xff 0x00 0xec

    ReplyDelete
  36. @backTo:
    I'm not sure what exactly are you asking, but your example (buffer[0] = 0x00 0xfc 0x00 0x01 0x03 0xff 0x00 0xec) is putting 8 _bytes_ data in to one byte of the array. Each byte is 8 bit.

    ReplyDelete
  37. HI ~

    Thanks to reply my question.
    but I'm sorry that I have one more question.

    I don't know why buff[1] is shifted 8bits...
    there..
    x = (((int)buff[1]) << 8) | buff[0];

    ReplyDelete
  38. It's written in the code comments. Each axis info comes as 2 bytes, that's why we Shift and Or, to merge two bytes in to one int.

    ReplyDelete
  39. working like a charm. thanks a lot for making my first 3d accelerometer experience so easy! :)

    ReplyDelete
  40. If you send the values of accelerations coming from the accelerometer with Serial.println using this codification: "x,y,z," then in the processing code you can simply use split() to get the values of the acceleration.

    Easier to understand IMHO.

    ReplyDelete
  41. How did you calculate the angular tilt/? Can you please explain the measurement equations/?

    ReplyDelete
  42. @Anonymous I assume you're talking about the Processing code?
    The code line for each axis is basically this:
    axis_val*(HALF_PI/255)
    I know that each axis value is between -255 (-1g) and 255 (1g) (unless i wave it real hard or something). I also know that full lean on one side (rotating the chip PI/2 radians, or 90 degrees) should give a reading of 1g. So, the formula simply converts the numerical value from -255 to 255 range to it's angular equivalent in the range of -PI/2 to PI/2.

    Hope it helped

    ReplyDelete
  43. Hey, great project! Looks like some of your code ended up in my project uncredited! Have a look at http://code.google.com/p/adxl345driver/

    It's been extended to support many of the features of the accel by Kevin Stevenard and myself, but it base looks a lot like your code.

    I'd be happy to add you to the author's list, or at a minimum, credit you in the source. Let me know what you'd like to do.

    Thanks for posting!
    Justin
    wyojustin@gmail.com

    ReplyDelete
  44. I have an arduino mega 328 and have tried uploading your code and I can't get it to work, i think may be because the mega has dedicated I2C pins (labelled SCL and SDA) and therefore i should be using these rather than the analog inputs, but i have tried wiring to these and it still just returns a reading of 0 for each axis. please help
    ps. pin 28 -->SCL
    pin 27 --> SDA for atmega328
    Thanks

    ReplyDelete
  45. I try to wire circuit like you but when I connected SCL and SDA from arduino ATmega328 with ADXL345 ...It didn't show anything on serial monitor and when I disconnect SCL and SDA .It usually shows value 0 0 0 ...recommend me please

    ReplyDelete
  46. @Justin Thanks a lot dude! I'll email you with the details

    ReplyDelete
  47. @bubu This is taken from the Arduino website, Wire library page:
    On the Arduino Mega, SDA is digital pin 20 and SCL is 21.
    So, you should use these pins for the Mega.

    ReplyDelete
  48. As possible that sensor ADXL345 doesn't work..

    ReplyDelete
  49. sorry for more question..
    my arduino's name is ETT board with ATMEGA 328P in datasheet of it
    pin 28 -->SCL
    pin 27 -->SDA
    pin 21 is AREF
    pin 20 is AVCC

    ReplyDelete
  50. Hi Euristic,
    this is the most comprehensive start-up cook book on the web, congratulations. However,...

    I am using a Arduiono Duelilanove, the ADXL wired to 3V3, GND, A4 and A5 with 10K resistors in place. I use your code as is @9600 with delay(500) at end of loop.

    Now, when the ADXL is laying flat on my table (not moving) I get readings like:
    11 4 248
    9 0 249
    5 -2 253
    15 2 248
    Why the readings are jumping, we can discuss later.
    After a while or immediately if I turn the ADXL around the X-Axis (Y is pointing upwards) then the USB connection to the PC hangs-up. Arduino IDE gives following message:

    java.io.IOException: Bad file descriptor in nativeavailable
    at gnu.io.RXTXPort.nativeavailable(Native Method)
    at gnu.io.RXTXPort$SerialInputStream.available(RXTXPort.java:1532)
    at processing.app.Serial.serialEvent(Serial.java:215)
    at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)
    at gnu.io.RXTXPort.eventLoop(Native Method)
    at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)

    Any idea, where to look (don't tell me check the wires, they are triple checked)

    Robert

    ReplyDelete
  51. @bubu you can email me and I'll try to explain in better details
    @Robert sorry dude, I'm not familiar with that problem, and sure about what might be causing it

    ReplyDelete
  52. Got mine working using I2C.
    CS needs to be connected to VCC and SDO needs to be connected to GND.
    Still trying to figure out how to get g's from the output.

    ReplyDelete
  53. @Sam correct, just like in the schematics :D
    In this setup the range of the output is -2g to +2g in 10 bit resolution. So, +255 on the output would be 1g. and -511 would be around -2g. So, to get g's from the output you need to divide the output by 255.

    ReplyDelete
  54. Euristic
    I've already success and understand bout adxl+arduino .Thank you very much for your concentration.But May I ask some question about your code in processing I don't under stand in code *HALF_PI/256 What's meaning..
    Thank you

    ReplyDelete
  55. hi
    can you please tell me why you have used i2c serial communication instead of spi.

    ReplyDelete
  56. How did you calculate only G-force in each direction?

    ReplyDelete
  57. HI... Can someone tell me how to turn on 4 LED when i tilt the accelerometer UP down , left and right... How can i take the value of X Y Z and Translate them to turn on a LED (as Output)...

    Thanks in advance...
    Nice Work:)

    ReplyDelete
  58. hi..i've tried this program on Arduino but its stated tat readFrom is not declared in void loop(). y is so?
    Thanks!

    ReplyDelete
  59. Hi , Tanks a lot 4 sharing this information with us :)
    could you tell me how did you make the 3D interface?
    you know, Im new here so I will appreciate if you explain how did you make the 3D interface?? and how did you export x , y , z value from arduino to this program.
    Thank You

    ReplyDelete
  60. u will nid to download processing and this guy actually provided the source code for both arduino and processing.

    ReplyDelete
  61. Thanks I found Processing, but the problem is Im designing my IMU (inertial navigation unit) and I need to program Quaternion rotation and Filters in MATLAB after that show the output as a 3D object so I don't know if in MATLAB I can do this? also I heard about a program called Phyton, so Im little confused :s

    ReplyDelete
  62. This post was my bible, thanks a lot.
    Just a question, maybe a silly question..
    I noticed that no gains have been settled in your code for each accelerometer axis, could different values be measured without setting any gain?
    I mean, having each axis oriented as the gravity, different values can be measured?
    Maybe it is not relevant for your graphical model, but it could be interesting

    Ciao
    Thanks
    Ferra

    ReplyDelete
  63. Hi guys, sorry for not answering for so long, will try to do my best to answer the latest questions.
    @budu: HALF_PI/256 - is the angle of the rotation, because 256 (from the adxl reading) is a full g.
    @Rinald: I used i2c because it was easier for me to set up.
    @Anonymous LEDS: simply output the the ADXL numbers through the Arduino digital pins and plug the LEDs in to them
    @Max: sorry dude, quaternions are beyound the scope of this tutorial
    @Ferra: sorry, I'm afraid I didn't quite understand the question

    ReplyDelete
  64. Hi Euristic, do u think you can help me with me adxl345 project. Relevant to what you previously did. Smt different is you need to output sentences at the serial port instead of values and activating the tap interrupt. I'm willing to pay your effort. Drop me a text. :)


    Jean

    ReplyDelete
  65. @Jean: If it's not too complex no compensation will be required. Drop me a mail at livefast.codeyoung@gmail.com

    ReplyDelete
  66. Hi !
    Thanks 4 all.
    What about signal voltage (ADXL345=3.3V Arduino 5.0V)
    I have 6DOF Digital from SparkFun
    http://www.sparkfun.com/commerce/product_info.php?products_id=10121
    Maybe You can comment on this setup
    Thanks
    Tom

    ReplyDelete
  67. Thanks a million. cut/paste=works first try!
    Using the 6DOF board from Sparkfun. Have gotten both to work independently, now to combine.
    to Anonymous 11/11/2010 - I used the Sparkfun logic level shifter # BOB-08745 and it seems to work great. I have the 5 volt UNO.

    ReplyDelete
  68. To Anonymous Nov 12 2010
    Thanks !!!
    Can You share some info - how did you wired it.
    I spent hours googling and serching but very little on ADXL345 & ITG-3200 almost zero on 6DOF Digital.
    Level shifter #BOB-08745 is unidirectional, I2C is bidirectional ???
    By the way have it (level shifter)
    Regards
    Tom

    ReplyDelete
  69. I cant see the photos?? Can you re-upload the photos? plis. Thanks a lot.

    ReplyDelete
  70. Sorry guys! My domain registration's ended, so I need to move the pics, hope I'll fix it today.

    ReplyDelete
  71. Hey. First of all, this is awesome Euristic!! A few questions though...

    I'm working on a project with 2 ADXL345 breakout boards from sparkfun. Is there a way for the arduino board to read data from both accelerometers simultaneously and then output it from the board?

    In our project, we actually want to use Zigbee to transmit the data from both accelerometers wirelessly to a computer. Do you know anything about the Arduino Xbee Shield and if it could work with this setup?

    Also, may seem like a stupid question... but how do i open the .pde files to view your source code?

    Anything you could offer would help SO MUCH. Thanks in advance,

    Collin

    ReplyDelete
  72. @Collin
    Hi Collin, I'm not sure about plugging in two ADXL345 to the same Arduino board, although there's a way to define two different device addresses for ADXL345 by different wirings (page 10 in the datasheet). Which means you can have two ADXL345 at the same time with different addresses, although I'm not sure how to divide the data wire.

    I'm sorry but I havn't really done any project with the Zigbee, so I can't really advise on that one.

    You can open all the sources in any text editor, I recommend notepad++. Hope this helped

    ReplyDelete
  73. Hey Euristic. I'm a senior at GWU in DC. So this is my senior design project. I'm trying to use two ADXL345s to measure the forces acting on the human knee during an impact.

    I'm still confused as to whether the ATMega328 could handle data from two different accelerometers. I'm not sure what you meant by defining different device addresses. There are enough inputs on the board to connect two ADXL345s aren't there?

    Also, I see that you connected the ADXL345 to the Analog inputs on the Arduino board. I thought that the output from the ADXL345 was digital, and therefore would have to use the PWM Digital inputs on the Arduino board. Would it be possible to connect it this way, or do you have to use the analog inputs?

    ReplyDelete
  74. OK So I have taken you code and tried it to modify it for the ADXL203/ADXRS610 combo board. but i get unexpected char 0x0 error when i try to compile can anyone help?

    import processing.opengl.*;
    import processing.serial.*;

    Serial sp;
    byte[] buff;


    int SIZE = 600, SIZEX = 800;
    int OFFSET_X = -28, OFFSET_Y = 9; //These offsets are chip specific, and vary. Play with them to get the best ones for you

    void setup() {
    size(SIZEX, SIZE, P3D);
    println(Serial.list());
    Serial port = new Serial(this, Serial.list()[0], 9600);
    buff = new byte[128];
    r = new float[3];

    }

    float protz, protx;
    void draw()
    {
    //delay(1000);
    //perspective( 45, 4.0/3.0, 1, 5000 );
    //print("ciao");
    translate(SIZEX/2, SIZE/2, -400);
    background(0);
    buildShape(protz, protx);

    String Xaccl = port.readStringUntil(10); //Modefied input from Serial.
    //String Yaccl = port.readStringUntil('\n');
    if (Xaccl != null)
    {
    //print(Xaccl);
    float[] Accl = float(split(Xaccl, ' '));
    float Y = Accl[0], X= Accl[1], Z=Accl[2];
    print(Y); // print("Y ");
    print(X); // print("X");
    print(Z); // println("Z");
    }

    float z = Accl[0], x = Accl[1]; //Modefied line
    if(abs(protz - Accl[0]) < 0.05) //Modefied line
    { z = protz;}
    if(abs(protx - Accl[1]) < 0.05) //Modefied line
    {x = protx;}
    background(0);
    buildShape(z, x);

    protz = z;
    protx = x;
    }

    void buildShape(float rotz, float rotx)
    {
    pushMatrix();
    scale(12,12,14);
    rotateZ(rotz);
    rotateX(rotx);
    //rotate(rotx, PI/2, rotz);
    fill(255);
    stroke(0);
    box(20, 5, 60);
    //fill(0, 255, 0);
    //box(10, 9, 40);
    //translate(0, -10, 20);
    //fill(255, 0, 0);
    //box(5, 12, 10);
    popMatrix();
    }

    ReplyDelete
  75. This works for me :

    In setup add 2 lines after the new Serial :
    Serial port = new Serial(this, Serial.list()[0], 9600);
    port.clear();
    port.bufferUntil(10);

    To get datas use the function serialEvent :

    void serialEvent (Serial p) {
    String buf = p.readStringUntil (10);

    if (buf != null)
    print (buf);
    }

    ReplyDelete
  76. Excuse me, but are there anybody successfully running the it on processing using Arduino mega 2560? I ran the sample code in Arduino IDE, that it is OK, but for the sample of processing, it doesn't work...I try to upload both StandardFirmata and I2CFirmata, but it failed..

    ReplyDelete
  77. Hi,
    thanks for the tip, you saved me a lot of time,

    I tried yor code and I noticed that there was a lot of variations in the values of acceleration.

    something like +- 5%, is it normal?

    and is there a optimal value for the pull-up resistors? does it affect the results?

    Thanks

    ReplyDelete
  78. Hi Euristic

    I got the ADXL345 breakout board today and got your code to compile.
    I have a really silly question, as this is my first attempt at using breakout boards.
    "Do you solder wires into the slots for GND,VCC, int1,int2 etc...? "

    ReplyDelete
  79. Hi Euristic,

    First off thanks for posting the set up and code for the adxl, it's super helpful. I plan on mounting the accelerometer to a rocket and I was wondering how to change the sensitivity to +/- 16g. I know that I have to make bits 0, 1 and 3 of register 0x31 to 1, but I don't know how to actually code this. For example, I was looking at the data sheet and it says in order to put the device in standby/measure mode then bit 3 of register 0x2D must be set to 0/1. Looking at your code, you accomplish this using the code:
    writeTo(DEVICE, 0x2D, 16);
    writeTo(DEVICE, 0x2D, 8);
    I don't understand how these lines of code correspond to setting bit 3 of register 0x2D to a value of 0 and 1, otherwise I would apply the same logic to changing sensitivity.

    Could you explain exactly how you got the values 16 and 8?

    Thanks a bunch,
    -BD

    ReplyDelete
  80. @Anonymous
    I've soldered pins to the breakout board so it fits a breadboard, or other places.

    @Brandon
    writeTo(DEVICE, 0x2D, 8);
    That's binary math. If you convert 8 to binary you get 1000. As you can see, if you count from right to left: zero bit is 0, bit one is 0, bit two is 0 and bit three is 1. Thus, we set the bit 3 to be 1.
    So, if you need to set bits 0,1 and 3, you should effectively put 1 in them. The number would be 1011. Then we convert this number to decimal it becomes 11 (8 + 0 + 2 + 1).
    writeTo(DEVICE, 0x31, 11);
    Is probably what you need.

    ReplyDelete
  81. Hi Euristic

    Great job!!
    I got your code running. How do i convert the values printed on screen to g's?

    Thanks
    Sam

    ReplyDelete
  82. Hi Euristic

    How did you decide on 255, to convert the values on screen to g's?
    The data sheet talks of resolution upto +-16g.
    How is the resolution set.
    Also in the code, for readFrom, you have
    Wire.requestFrom(device, num), but then num, never seems to be used?

    Thanks
    Sam

    ReplyDelete
  83. @sam
    -/+2 g is in the range of -512 to 512 (signed 10 bit resolution) - it's explained in the post. How th resolution set is also explained in the post and the datasheet. Wire.requestFrom(device, num) num is used to determine how many bytes you want to read it is also explained in the post just under the readFrom function.

    ReplyDelete
  84. This post saved me a ton of time! I received zero values at first, but fixed a bad solder (SLA on the ADXL), and was up and running in no time with my Mega 2650.

    Thanks!!
    William

    ReplyDelete
  85. Hi Euristic,
    Two friends and I are working on a high school project together. We're trying to assemble an accelerometer and mount it on a rocket to study its flight dynamics. Do you think this could do the trick?
    Thanks!

    ReplyDelete
  86. hi euristic its the high schooler again...
    what arduino board would you recommend we use? we were thinking the pro mini (our rocket's diameter is 1.9") because it needs to be small. any thoughts?

    ReplyDelete
  87. Thanks a bunch for the kickstart on this one Euristic! Since I got a lot from your page I thought I'd contribute one quick bit since there was some confusion earlier in the comments and I just figured this out.

    If you change resolutions, the following happens:

    +-2g, divide output by 256 to get g's
    +-4g, divide output by 128 to get g's
    +-8g, divide output by 64 to get g's
    +-16g, divide output by 32 to get g's

    This is how it appears to work for me. It makes sense, the number of bits/g decreases. Anyway, just in case others are reading through for their first time and confused.

    Thanks again!
    Bill

    ReplyDelete
  88. Hello,
    I just wanted to thank Euristic for making the community a better place =)

    @High Scooler: i have the mini pro hooked up to the adxl345, its working very nicely tho the acquisition rate is kinda slow - a few tens of hertz. Not very much that can be done about that, it seems to be the limit for the i2c protocol here, but it could surely be used for your project! you can find some nice lipos on sparkfun and i would recomend the 3.3V mini pro, so you can also write on a sd card directly with no voltage conversion.
    Cheers!
    Davide

    ReplyDelete
  89. Thanks a lot for the interest guys! Sorry for the delayed reply highschooler, I see that Davide already answered you. Good luck with your project :)

    ReplyDelete
  90. Davide and Euristic,

    We really dont know much at all about programming and the physical requirements of it. But in the pictures that you posted, I see that the white board seems to be bigger than a couple inches. Is there any way to get this whole setup to fit inside the 1.9" diameter rocket?

    Rocket Team

    ReplyDelete
  91. @Rocket Team
    Hi guys, you are only limited by the size of the Arduino you are going to use, according to SparkFun (http://www.sparkfun.com/products/9950) the Arduino Uno is 2.1" x 3". So that might not fit your rocket. If you use a smaller Arduino it will work as you don't need the breadboard (white panel), it's there only for ease of use.

    ReplyDelete
  92. Thanks! Btw we selected the Arduino Pro Mini because of its size so it sounds like it should work fine.

    ReplyDelete
  93. @Davide or Euristic!

    Rocket team again..
    Our adxl345 and 3.3v mini pro arrived so we need to put together our setup. With this blog and other schematics online we can hookup the accelerometer and the arduino but how exactly do you make the accelerometer write the data on an SD card?

    ReplyDelete
  94. never mind on that last post

    -RT

    ReplyDelete
  95. Thanks for the code example! It works fine for me with
    IMU Digital Combo Board - 6 Degrees of Freedom ITG3200/ADXL345

    ReplyDelete
  96. Hi Euristic,
    I got a problem, processing read the values but it can't move.
    I got arduino mega 2560.
    Do you have any idea ?

    ReplyDelete
  97. @Dangrod if processing reads the values it should move the model alright, unless the values are rubbish - and not what the accelerometer actually reads.
    Did you make sure you connected the wires correctly, on the mega the clock and data wires are different than on the normal arduinos (instead of 4 and 5 it's 20 and 21 on the Mega).

    Hope it helps

    ReplyDelete
  98. Yes, the value are correctly read, it's why I don't understand why its not work.

    ReplyDelete
  99. Euristic!

    Me and my friends have our code written and we assembles the connection for the Pro Mini to connect to our computer, but we keep getting error messages when we try to upload the code. The same ones every time, "not in sync" and "protocol error". Any idea whats going on?

    RT

    ReplyDelete
  100. Nice piece of code and great instructions. Thanks

    ReplyDelete
  101. I had a really hard time making this sensor work properly, before i found this post.

    Thanks a lot, works great!

    Regards,
    benja

    ReplyDelete
  102. I always get 0 0 0 0.
    SDA goes to ANALOG 4 or 5???
    http://arduino.cc/en/Tutorial/MasterReader

    I use Arduino Dumilanove, MACm and ADXL345

    :(

    ReplyDelete
  103. @nachoad Sorry for the late reply, SDA goes in to ANALOG 4 like it's drawn in the circuit scheme.

    ReplyDelete
  104. does it works with ATmega168?

    ReplyDelete
  105. Supposed to work with Duemalinove (any chip) as showed

    ReplyDelete
  106. Does it also work with Arduino Fio in combination with the Xbee shield? And if so, is it true that I have to use the digital inputs? Thanks a lot for your help!

    ReplyDelete
  107. @Jour Sorry for the late reply. I don't know what Fio is, but generally it should work with any Arduino who can run the Wire library

    ReplyDelete
  108. Hi Euristic

    thank you for ur generosity and ur awesome effort!

    I have a question that (as i can see) has been asked a couple of times, but i can't seem to get an answer, i hooked up the circuit 4 times(just to recheck) and even pasted your code exactly, i still get zeros(0000) as output :( :(, u said before that in the setup() method, there is a statement that gets the accelerometer out of sleep mode, i did that still won't work, any idea wuts wrong?

    ReplyDelete
  109. @BigBoi! very welcome, thanks for the kind response :)
    The last person I've talked to who had this problem simply had a problem with the soldering, the contacts were bad.
    So, this might be one of the problems you should check first (bad/wrong wiring, bad pins on the breakout board etc).

    Good luck :)

    ReplyDelete
  110. Hello Again Euristic:D

    Sorry for the bother, i have been able to succesfully apply ur circuit and ur code just works out great.
    the only thing is, i want to transmit the data from the accelerometer via Xbees to another one and recieve them on the other end.

    The problem is, assuming i sent the reading and reach the serial in this format (2 3 100)
    How can i parse them and assign them to distinct variables? ive been trying to do that for quite sometime with no success.

    thank you again for being so helpful. :D :)

    ReplyDelete
  111. @BigBoi!
    Sorry for the long reply time. What hardware do you have on the receiving end? If it's another arduino, you can simply parse the values by spaces. If it doesn't work out, please drop me a mail.

    Good luck

    ReplyDelete
  112. No problem :D:)
    yes its another arduino, the only problem is, im confused about the way data types are handled in arduino, specifically the Serial.print and "byte" and "char" data types... a brief elaboration on that part would be greatly appreciated :D

    ReplyDelete
  113. like, if one arduino transmits (-1 -1 180)
    how can i print the to serial that same way and parse them on the other end and set x=-1 y =-1 and z=-1 :D ... thank you :D

    ReplyDelete
  114. Hey this is slightly a stupid question. If i don't solder the ADXL 345 and just put wires through the holes of the ADXL would it work? Cause i've hooked it up this way but i don't get any readings when i run the program. Its all 0 0 0.

    ReplyDelete
  115. Also i can't tell if the ADXL has led's on it. I think i might of connected it wrong the first time and possible burnt it out. =(

    ReplyDelete
  116. Okay im sure that the connection is not the problem. And the ADXL is getting power and setting cs high and sdo low. i followed the schematic/ picture and it is right. I'm still getting all 0s.

    ReplyDelete
  117. I think my drivers might be the problem. My arduino shows up in COM5 for every port i plug it into. I think that might be why im getting all 0s in the com port. Anyone know what to do? I posted this question in the Arduino forums also

    ReplyDelete
  118. Sorry for the spam of posts. There is nothing wrong with my arduino. The hook up is right. So i'm not sure what the problem is =(

    ReplyDelete
  119. wow... thanks for adding a lot of details to the code, some of it was a bit mysterious (binary thing, right to left )

    oh and mentioning a bad solder joint....

    *&^*($$&&(^**%$!!!!! solder joint - that was it...

    (i owe my wife flowers for putting up with my foul mood because of that stupid bad solder joint)

    ReplyDelete
  120. Thanks a lot man, REALLY appreciate your effort and willingness to share your knowledge!

    ReplyDelete
  121. Very welcome :)
    Flowers for the wife is always a good idea btw ;)

    ReplyDelete
  122. Hi, nice work =D
    I have a question, Can I connect 2 acelerometers (ADXL345) in one arduino ? How ?
    Thanks.

    ReplyDelete
  123. Hi Anonymous,
    I've never tried it (I only have one ADXL), but using the Wire library I think you are limited to one device a time (because you have only one data channel). So I think you'll have to figure out some sort of switch to turn the not needed adxl off each time. This is just a thought though. Hope it helps.

    ReplyDelete
  124. In the setup function, you wrote
    "
    writeTo(DEVICE, 0x2D, 0); //binary 00000000
    writeTo(DEVICE, 0x2D, 16); //binary 00010000
    writeTo(DEVICE, 0x2D, 8); //binary 00001000
    "

    In the first command you are setting everything in the address 0x2D to 0 in the second one you are enabling AUTO-Sleep and in the third one you are disabling AUTO-Sleep and enabling measuring bit.

    Is my understanding of the initialization provided in the code, correct?

    ReplyDelete
  125. Hi,
    I have connected two adxl345 to one arduino pro.In the datasheet of the accelerometer, (page 10) it says that you have define two different device addresses for the accelerometers.One of them is 0x53 , the other one is 0x1D. Of course for the device(0x53) you should connect SDO pin to the ground and for the device(0x1D) SDO pin to high.Then you can communicate these devices by coding differently. one data channel is enough for that.i mean the bus is used seperately in time.
    By the way nice work Euristic.
    and also sorry for my english:)

    ReplyDelete
  126. Hi
    Thank you very much for this. I am basically new to this and i have been assigned to retrieve the accelerometer value of a moving vehicle . can you please tell me what kind of software you use in the PC ,that will show the value of accelerometer retrieved ?

    ReplyDelete
  127. The info which is provided is really helpful.Can yo pls say where i can get info about the SPI,I2C interface

    ReplyDelete
  128. Dear Euristic:

    Thanks for all the information and this "how to". I learn a lot,especially thinking than i am new in this.

    The code works perfect, i'm using a seeeduino Atmega328p with the ADXL345.

    I only have one problem, i can't make run the matching processing application to read the data. When compile, a lot of error are found. I have to use other aplication? use both on alduino enviroment?.

    Thanks again.

    ReplyDelete
  129. Thanks!

    I used this design and program to test an ADXL345 for our FIRST Robotics project. The accelerometer works, which means our problem is elsewhere. That is progress.

    -Larry

    ReplyDelete
  130. Hey guys, sorry for not replying for long, was on a long vacation :)
    1. Thanks a lot for the double connection info! People are asking a lot about that.
    2. I'm using the Processing programming language to retrieve the data (I have another post about it)
    3. I think you should google SPI and I2C (that's what I did)
    4. I'm not sure what error you're getting. I'm using the Processing IDE to run the processing app (have a post about it).
    5. Larry, glad to hear that, good luck with your project! :)

    ReplyDelete
  131. Hi Euristic,

    Great tutorial. I am doing an university project where I am using the adxl345. I need to have a graphical interface and I saw that you were using the processing language. I had questions about your code

    Can you explain these lines in detail?

    int bytes = sp.readBytesUntil((byte)10, buff);
    String mystr = (new String(buff, 0, bytes)).trim();
    if (mystr.split(" ").length != 3) {
    println(mystr);
    return;
    }

    The reason I ask is because I want to modify the code to just plot the x value of the accelerometer. This values are sent in groups of 170 x coordinates with space characters in between and a new line character at the end.

    e.g. "0 1 0 2 10 4 4 6 7 3 ...."

    Thanks

    ReplyDelete
  132. Hi Anonymous,
    in general, this snippet takes one line sent by the Arduino, parses it, checks if it actually got 3 values (for x, y and z), and if it DIDN'T it prints the problematic string and returns.

    The first line checks how many bytes there are until new line.
    Second line generates a clean (trimmed) string from buff, but using only the chars BEFORE the end of line.
    The "if" statement checks if there are exactly 3 values separated by spaces. If the number of values is not 3, the function returns (does not continue this iteration).

    In general, I think you could use it, and only change the number to 170 (of course you'll have to alter the code beyond that point from x-y-z logic to only one axis).

    Hope it was clear enough. Good luck with your project!

    ReplyDelete
  133. Hi there great tutorial but i have a problem. I have connected everything fine and im getting values from the accelerometer through the arduino serial monitor but i am unable to make the processing sketch do anything or even move. the processing sketch has a line saying COM4 whereas my arduino mega is com23. i tried to change it but it just came up as saying error. what can i do to fix this and get the processing app to work. do i need to place a specific file within a processing library?

    ReplyDelete
  134. @TheDeveloper hi! Are you sure your Arduino mega is on com port 23? You should try and check in the Arduino IDE's Tools > Serial Port in order to make sure (it is usually COM3). More details can be found here: Select your serial port

    ReplyDelete
  135. Hello

    I need the accelerometer to operate using +/- 16g. I have altered the main example code: 'accel.SetRange(16, true); ' and also changed the .cpp and .h codes to use uint16 instead of uint8. I am using the '#define ScaleFor16G 0.0312' but i receive XValue= 1.03G, YValues = 0.34G and ZValues = 6.68G. Shouldn't this scale provide me with XValues = 0G, YValues = 0G and ZValues=1G at rest with the possibility of +/- 16G??

    Can anyone tell me where i am going wrong with adjusting the accelerometer for +/-16G?

    ReplyDelete
  136. Hi, the code you're talking of is from another tutorial.

    ReplyDelete
  137. I have been seen in the datasheet of ADXL345, but I don't know where I can find the Offset_x and offset_y, help me .

    Thanks

    ReplyDelete
  138. Hello there Euristic!

    I'm just gonna ask something related to Arduino Pro Mini v328.
    Is it possible to connect 5 digital accelerometers in it? one 3-axis, and four 2-axis...

    I hope to read your response. I think we'll going to cram on our project.

    Thanks

    ReplyDelete
  139. @IwannaKnow I'm not really familiar with the Pro Mini, but if it has the same interfaces as the Duemilanove then it mainly depends on the accelerometers you're plugging and the interfaces they're using. If your accelerometers are analog it should be relatively easy to set things up.

    ReplyDelete
  140. Thank you Euristic..

    I'm using a digital one so I'm more confused on how I should start it..

    ReplyDelete
  141. Hello! First of all congratulations for your post!!! I have an ADXL335 where the axis are sent individually. Do you have a suggestion how can use your code suggestion to interface with this kind accelerometer? (My email is deoclecio.jr@gmail.com)

    Best Regards,
    Deoclecio

    ReplyDelete
  142. One question: I tried to run the codes using Arduino but didnt work. Using PROCESSING, I had problem in Wire.h line. Could me give details with (Processing or arduino software) do i have use?

    Regards,
    Deoclecio

    ReplyDelete
  143. @Deoclecio Fernandes
    hi, you will be able to use the Processing part of the code unchanged, but you will need to rewrite completely the Arduino part. From what I see adxl335 is an analog device, and should be easier to wire and work with. I'll continue this in an email

    ReplyDelete
  144. Hi,

    thanks a lot for sharing this project. So happy it worked the first time!

    The only 2 things I had to change in the original code are:
    - Replace Serial.print(10, BYTE) with Serial.print(byte(10))
    - Rename Wire.send and Wire.receive to Wire.write and Wire.read

    Riccardo

    ReplyDelete
  145. Hi,
    I have a problem. I have connected everything fine and I'm getting values from the accelerometer through the arduino serial monitor but I'm unable to make the processing sketch do anything or even move. The processing sketch has a line saying COM6 as my arduino Duemilanove is COM6. What is wrong? Why it does not work? Please, could you help me?
    Thank you.

    ReplyDelete
  146. @Riccardo thanks for the info dude. What board are you using?

    @Anonymous hey man, can you post the exact error that Processing is giving you?

    ReplyDelete
  147. Hi Euristic,

    I see a picture with sensor, but I don't see any movement when I move with sensor.

    ReplyDelete
  148. Are you getting an error? If yes, what does it say?

    ReplyDelete
  149. If I run a program at Processing 32 bits, Processing don't write error, I see a picture with sensor, but I don't see any movement.
    If I run a program at Processing 64 bits, Processing writes Error inside Serial.() and I see only white small window.
    I have windows 7 64bits. The program is the same.

    ReplyDelete
    Replies
    1. My mistake. I run first program at Processing 32 bits and don't close it and after I run program at Processing 64 bit. Now I run program only Processing 64 bit and Processing writes no error and I see a picture with sensor but I don't see any movement when I move with sensor.

      Delete
  150. Did you ever get around to doing the processing code part?

    ReplyDelete
  151. I am not sure what you're asking

    ReplyDelete
  152. hi im found net interesting code but code have use ADXL203 sensor and i no can orden anywere old 203 model, have all shop only ADXL 345 model,can i use new modell and what need change at code working good ?
    project have wery interesting but old swnesor and need use new sensor model there is project code---> http://segwayrobot.blogspot.fi/2011/10/small-scale-segway-prototype-running.html
    sorry im newbie at arduino and thats my 3th project, :D

    ReplyDelete
  153. @Matti Virta hi, sorry have no idea, I'm not familiar with that device.

    ReplyDelete
  154. Hi,I wanted to know whether is it possible to run the code on MPU6000 used in quadrotor..
    This is for my masters project and I am just at the start of it...

    ReplyDelete
  155. @aswathy menon Looks like a completely different piece of hardware. I think you might try to use the Processing code, but for the Arduino/ADXL combo you'll probably need to heavily modify it. (Depending on the communication protocols and addresses and commands)

    ReplyDelete
  156. Hi,Thanks for the tutorial.I wanted to know if the code takes care of the initial offset calibration of the adxl345.I am getting approximate readings like -400,-95,690 at resting position on a flat surface.

    ReplyDelete
  157. @Anonymous you're welcome! There's initial offset on the Arduino side, although I do compensate on the Processing side.

    ReplyDelete
  158. Hi! Could you help me, please, I use your's code for ADXL345 in ARDUINO 1.0.1, so I rewrite method "Wire.reseive(...)" for "Wire.read()" and method "Wire.send(adress)" for "Wire.write(adress)" (Arduino 1.0.1 shows errors if I use "receive" and "send" methods). When the ADXL345 is static (I put it on the table) I get the next values:
    -11 -14 214
    -12 -13 229
    -12 -13 231
    -13 -13 232
    -13 -15 234
    -13 -15 234
    ...
    I don't understand how to get values in g, I need use the acceleration from ADXL345 for detecting speed and distance. Tell me please, what are the values -13 -15 234??? And how to get the values of acceleration? And else, using your's code, is ADXL345 master or slave? I also using gyro ITG3200 and it's simple with its library, but ADXL345 is not simple.

    ReplyDelete
  159. Hi there. The adxl in this code is the slave. Now for the values, these are the accel values per axis separated by spaces. First value for x, second for y and third for z (z is the up/down axis). To translate the values t g's, divide them by 255. That way, in resting position you'll get something close to 0 on x and y, and something around 1 on z.

    Hope this helps!

    ReplyDelete
  160. FROM Anonymous March 22, 2013 at 2:19 PM (My name is Nikita)

    It's GREAT!!! VERY VERY TANK YOU!!! It's work and there is the values I've got when the ADXL345 is static:

    -0.06 -0.06 0.91
    -0.06 -0.06 0.91
    -0.06 -0.06 0.91
    -0.07 -0.06 0.86
    -0.09 -0.06 0.91
    ...

    and when I move it:

    -0.02 -0.07 0.22
    -0.04 -0.15 0.20
    0.02 -0.05 0.47
    ...
    0.55 0.87 1.22
    0.55 1.03 1.21
    0.64 1.13 1.11
    ...
    -1.18 -0.32 1.01
    -1.22 -0.45 0.98
    ...

    THANKS!!! You are GURU!!! Yours code is only wich works. I used "Love Electronics" library for this sensor using their Electrical Connections, but it did not work(((

    ReplyDelete
  161. Hi excellent tutorial! I have one question about the hook up the ADXL with Arduino. Can I hook the SDO to CS instead of hook to GND. My hands are too itchy hook it too fast, I'm following the Love Electronics hook up method. https://www.loveelectronics.co.uk/Tutorials/12/adxl345-accelerometer-arduino-tutorial

    Looking forward to your reply! My email is yeochowshern@gmail.com

    ReplyDelete
  162. @ChownShern why would you want to hook SDO to CS?

    ReplyDelete
  163. Serial.print(10, BYTE); is not supported on arduino 1.0.4
    What should I do?

    thanks

    ReplyDelete
  164. @Anonymous thanks for the heads up! Code is now updated to work with 1.0.4 and the new Wire lib (write/read instead of old send/receive)

    ReplyDelete
  165. Hi,
    I was wondering if anyone tried connecting 2 adxl345 to arduino via I2C(Wiring too please). Can anyone tell me what to do and where. Here is the code I used to communicate 1 adxl345 with arduino via I2C.
    // Cabling for i2c using Sparkfun breakout with an Arduino Uno / Duemilanove:
    // Arduino <-> Breakout board
    //Accell - 1 (0x53)
    // Gnd - GND
    // 3.3v - VCC
    // 3.3v - CS
    // Analog 4 - SDA
    // Analog 5 - SLC

    //Accell - 2 (0x1D)
    // Gnd - GND
    // 3.3v - VCC
    // 3.3v - CS
    // Analog 2 - SDA
    // Analog 3 - SLC

    #include

    #define DEVICE (0x53) // Device address as specified in data sheet

    byte _buff[6];

    char POWER_CTL = 0x2D; //Power Control Register
    char DATA_FORMAT = 0x31;
    char DATAX0 = 0x32; //X-Axis Data 0
    char DATAX1 = 0x33; //X-Axis Data 1
    char DATAY0 = 0x34; //Y-Axis Data 0
    char DATAY1 = 0x35; //Y-Axis Data 1
    char DATAZ0 = 0x36; //Z-Axis Data 0
    char DATAZ1 = 0x37; //Z-Axis Data 1

    void setup()
    {
    Wire.begin(); // join i2c bus (address optional for master)
    Serial.begin(19200); // start serial for output. Make sure you set your Serial Monitor to the same!
    Serial.print("init");

    //Put the ADXL345 into +/- 4G range by writing the value 0x01 to the DATA_FORMAT register.
    writeTo(DATA_FORMAT, 0x01);
    //Put the ADXL345 into Measurement Mode by writing 0x08 to the POWER_CTL register.
    writeTo(POWER_CTL, 0x08);
    }

    void loop()
    {
    readAccel(); // read the x/y/z tilt
    delay(500); // only read every 0,5 seconds
    }

    void readAccel() {
    uint8_t howManyBytesToRead = 6;
    readFrom( DATAX0, howManyBytesToRead, _buff); //read the acceleration data from the ADXL345

    // each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!
    // thus we are converting both bytes in to one int
    int x = (((int)_buff[1]) << 8) | _buff[0];
    int y = (((int)_buff[3]) << 8) | _buff[2];
    int z = (((int)_buff[5]) << 8) | _buff[4];
    Serial.print("x: ");
    Serial.print( x );
    Serial.print(" y: ");
    Serial.print( y );
    Serial.print(" z: ");
    Serial.println( z );
    }

    void writeTo(byte address, byte val) {
    Wire.beginTransmission(DEVICE); // start transmission to device
    Wire.write(address); // send register address
    Wire.write(val); // send value to write
    Wire.endTransmission(); // end transmission
    }

    // Reads num bytes starting from address register on device in to _buff array
    void readFrom(byte address, int num, byte _buff[]) {
    Wire.beginTransmission(DEVICE); // start transmission to device
    Wire.write(address); // sends address to read from
    Wire.endTransmission(); // end transmission

    Wire.beginTransmission(DEVICE); // start transmission to device
    Wire.requestFrom(DEVICE, num); // request 6 bytes from device

    int i = 0;
    while(Wire.available()) // device may send less than requested (abnormal)
    {
    _buff[i] = Wire.read(); // receive a byte
    i++;
    }
    Wire.endTransmission(); // end transmission
    }

    ReplyDelete
  166. @sathish Dude, you should read the datasheet before attempting such endeavors :) I havn't connected two adxls myself, but I'll point out some clear mistakes: First of all you connected the second adxl to analogs 2 and 3. Why? You're also mixing axis addresses of the two adxls - they are the same on BOTH the accelerators, you simply read them one adxl after the other. Your device address on the other hand is the same for both devices - which is wrong, because device address is how the adxls are told apart. Hope this helps you to move forward

    ReplyDelete
  167. Hi Euristic,
    Thanks for pointing that out. I tried with the corrected connection and modified code it seems to be working now.

    ReplyDelete
  168. Hi,
    My setup is 16g (13 bit resolution), so the equation is it going to be
    = valueX * (13/8162) = 0.001953125

    is it correct, or im missing something

    thanks in advance

    ReplyDelete
    Replies
    1. Hi there,
      in general one G is 255 units in 16g/13bit setup. So to translate a value to G's you simply divide it by 255.
      valueX/255

      You can also look in to the Processing app provided in the source files, it shows an example of how to use the data provided by the Arduino.

      Delete
  169. Thanks for the reply,
    to make the processing 3d works, what is the format it receives, im sending the data like this:


    IntToStr(readings[0], out);
    UART1_Write_Text(out);
    UART1_Write_Text(" ");
    IntToStr(readings[1], out);
    UART1_Write_Text(out);
    UART1_Write_Text(" ");
    Delay_ms(100);
    IntToStr(readings[2], out);
    UART1_Write_Text(out);
    Delay_ms(100);

    but there is no any change in the processing 3d sw

    ReplyDelete
    Replies
    1. This comment has been removed by the author.

      Delete
    2. I got it working, but the values from the accel. are crazy

      Delete
  170. I got this, when i start it, (to be noted, im using PIC controller 18f45k22 SPI to ADXL345)

    this is how i init. the accel.

    // Go into standby mode to configure the device.
    ADXL345_Write(_POWER_CTL, 0x00);

    // Full resolution, +/-16g, 4mg/LSB.
    ADXL345_Write(_DATA_FORMAT, 0x0B);

    // Set data rate.
    ADXL345_Write(_BW_RATE, _SPEED);

    // Measurement mode.
    ADXL345_Write(_POWER_CTL, 0x08);

    and these are the data i get.

    -13568 7680 -5632
    7680 7168 -7680
    7168 7168 -7168
    8192 6144 -5120
    6656 7168 -4608
    6656 5120 -5120
    5120 6144 -2560
    5120 8704 2561
    512 5632 -5120
    7168 7168 -4608
    7680 6144 -3072
    6656 7680 -6656
    6144 8704 -4096
    6656 6656 -3584
    7168 6144 -5632
    6144 7680 -3072

    ReplyDelete
    Replies
    1. Sorry man, not familiar with PICs. In any case, I would check the resolution, and/or try to normalize the values with some constant multiplier.

      Delete
    2. Hi, I made it working (I think so)..
      here are the data I received:

      -21 13 229
      -19 12 231
      -22 12 231
      -20 14 231
      -20 13 232
      -21 13 229
      -21 13 228
      -21 13 230
      -21 14 229
      -23 12 231
      -21 13 229
      -17 10 227
      -21 13 228
      -20 12 228
      -24 15 225
      -21 13 230
      -21 14 229
      -22 16 226
      -21 12 230

      but when i run the 3d processing SW, its just not moving and giving me an exceptions in the starting of the program,

      Framebuffer error (framebuffer unsupported), rendering will probably not work as expected
      OpenGL error 1280 at bot beginDraw(): invalid enumerant
      Stable Library
      =========================================
      Native lib Version = RXTX-2.1-7
      Java lib Version = RXTX-2.1-7
      OpenGL error 1286 at bot endDraw(): invalid framebuffer operation
      OpenGL error 1286 at bot beginDraw(): invalid framebuffer operation

      OpenGL error 1286 at top endDraw(): invalid framebuffer operation

      thanks in advance :)

      Delete
    3. Dude, let's do this via emails. Awaiting your mail

      Delete
    4. sure,
      eng.hasan.power@gmail.com

      Delete
  171. hi, i am now doing this as my project, may i know which software that you use for the real-time 3D processing? can provide the code and the setting?

    ReplyDelete
    Replies
    1. Hi there,
      I'm using the Processing language for the 3d. The sources for the setup are provided at the end of the post.

      Delete
  172. That's a well done tutorial! Thanks!

    ReplyDelete
  173. Hi, thanks for great help to enter this area of electtronic))
    Please, would you have any idea why I got strange data, I mean in X-axis I will not get more than 124 and it barely changes aorund that straight down position... I try to recalculate it to degrees and have no idea what is wrong...
    When I downloaded also Processing and run directly your files, I am able to get tilt of the model max to cca 45° with ADXL upside down and value for tilt over 90° changes jut a very little.
    Any idea to test?
    Thanks for any help...
    brgds,
    Mirek von Zlin, CZ

    ReplyDelete
    Replies
    1. Hi there, do you the same problem on every axis, or only on X?

      Delete
  174. Euristic, i cannot express how grateful im now. Thanks, really, this post has been very helpful.

    ReplyDelete
  175. i know it has been asked , but really it returns 0 !
    i don't why ?

    ReplyDelete
    Replies
    1. Hi Sherif, have you ran the code from the courses as it's provided? Also make sure you've wired the board correctly.

      Delete
  176. Hi Euristic,

    Thanks a lot for the tutorial! Anyway, I got everything connected. And then I verify and upload on the Arduino program. It says Done Uploading. And shows "Binary sketch size: 5,852 bytes (of a 32,256 byte maximum)"

    Then I go on to Processing(64 bit) it says serial can only work on Processing(32 bit). My computer is 64 bit windows 7. So I run using Processing (32 bit), and it comes up with a small grey window with nothing inside. What am I doing wrong?

    Thanks!

    ReplyDelete
    Replies
    1. Hi, it's me again.

      Euristic,
      I realised it was set to COM4 while my Arduino Uno was in COM18. So I changed the code to COM18, however, it seems that Processing is receiving some junk data at the beginning causing it to get errors. The junk data can also be seen in Arduino Serial Monitor:
      227
      48 -36 226
      48 -¦ ’’²þ48 -36 226
      45 -33 215
      48 -37 228
      49 -34 228
      48 -35 228
      48 -36 226

      Causing Processing to display this "49 -& ’’ÿ48 -36 227"
      OpenGL error 1286 at bot endDraw(): invalid framebuffer operation
      Framebuffer error (unknown error), rendering will probably not work as expected
      OpenGL error 1286 at top endDraw(): invalid framebuffer operation

      Help is much appreciated. Thanks!

      Delete
    2. Hi Anonymous,
      I'm not sure why these bad values appear, but you could filter them in the Processing code, by checking if every value in the set is a valid number.

      Delete
    3. Hi Euristic,
      It's me again. This time, I keep getting OpenGL error even though my COM port is 4 or 18. 4 contains nothing and 18 is my Uno. Since this OpenGL error comes up on both the ports, I dont think its the bad value causing it anymore. What do you think is causing the OpenGL error?

      Delete
    4. I've no idea what error you're getting, so I can't be of much help here.

      Delete
  177. very good guide how to use gyro and accelerometer sensors. I add this tutorial on my article where a long list with sensors and tutorials about how to interface and programming accelerometer, gyro and IMU sensors http://www.intorobotics.com/accelerometer-gyroscope-and-imu-sensors-tutorials/

    ReplyDelete
  178. hey, u made this working for arduino. but im working on msp430 launchpad along with Energia software.this software is similar like arduino one. so can you help me with the code pls.

    ReplyDelete