jumejume1 / ax-12a-servo-library

Dynamixel AX-12A Robot Actuator

AX-12A Datasheet

Installing the library

• Download zip file
• Extract zip
• Rename the folder : AX-12A-servo-library-master --> AX-12A-servo-library
• Put the folder into your library folder (usually Documents/Arduino/libraries)

Using the library

To use the library, include header file located in the src folder.

#include "AX12A.h"

The library is provided with 4 Arduino examples :

• Blink : simpliest example to blink the built-in LED
• Move : example showing how to set a goal position
• EndlessTurn : example of endlessTurn mode (wheel mode)
• readRegister : debug AX-12A by printing all its registers

You have 4 lines to configure :

#define DirectionPin  (10u)
#define BaudRate      (1000000ul)
#define ID            (1u)
...
AX12A.begin(BaudRate, DirectionPin, &Serial);

DirectionPin is the GPIO used to change communication direction.

BaudRate corresponds to the baud rate used to communicate with the servo.

ID corresponds to the ID of the servo (from 0 to 253, 254 is used for broadcast).

&Serial refers to the serial port you want to use. It may have to be changed to &Serial1, &SerialUSB or other depending on the board package you use (variant files).

Change AX-12A settings by connecting the servo to a PC via USB2Dynamixel.

To do so, install Dynamixel Wizard included in the RoboPlus software suite.

Follow these instructions to connect and access the AX-12A settings.

Baud rate tests

We tested the library on differents boards at the most common baud rates.

Some boards cannot reach the desired baud rate :

Address 0x04	Baud rate	Feather M0	Feather 32u4	nRF52	STM32L4
1	1000000	ok	ok	ok	fail
3	500000	ok	ok	fail	ok
4	400000	ok	fail	fail	ok
7	250000	ok	ok	ok	ok
9	200000	ok	ok	fail	ok
16	115200	ok	ok	ok	ok
34	57600	ok	fail	ok	ok
103	19200	ok	ok	ok	ok
207	9600	ok	ok	ok	ok

ax-12a-servo-library's Issues

#include <HardwareSerial.h>

In <AX-12A.h> author forgot to #include <HardwareSerial.h> and it causes to few errors while compiling file. Maybe i did something wrong, but when I wrote this string, example code start to work fine.

no such file or directory

The library loaded into arduino ok, but compiling a simple example gives:
../../src/AX12A.h: No such file or directory

Position reading

I am reading the position while I move the servo as ENDLESS mode and it outputs from 0 to 1023 which is correct, but I can see that after it reach 1023 it returns 3-4 reading at 400 or 600 ( it is random ) then starts again from 0 ( which is correct ).

Is there an issue on the decoding of the position?

Specials, Instruction Set and Status Return Levels in AX12A.h file

Greetings,

I am going through your code for AX-12A dynamixel and I wish to write similar library for XC330-M288-T. I came across varible defination in file AX12A.h. After comments name Specials, Instruction Set and Status Return sections the varible that you declared, I cannot find it on e-manual. I want to know from where you used it. So I can also use it for XC motor.

Possible to enable unlock?

I wonder if there is a mode to unlock or disengaged the motor, like when it is not powered and you can move the wheel freely.

I couldnt find any combination of changing to wheel or remove torque that will make it "idle", maybe is not possible unless is not powered, do you have any clue if it can be done via code?

XL430-W250-T with AX12A

Is it possible to control a Dynamixel XL430-W250-T Servo with this AX12A library?