Looking for documentation about Pololu servo controller

Hi all,

Am looking for documentation and connecting about this servo controller. So far i haven't found anything.

https://www.pololu.com/product/207

Can someone point to some websites besides the information provided by Pololu self ..like example code etc

thx in advance

Click the “Resources” tab on the Pololu web page ?

…R

Robin2: Click the "Resources" tab on the Pololu web page ?

...R

aye found docs there but no luck how to communicate with the servo controller

In this document I found this

Protocol. To set the servo position, send a sequence of three bytes. The first byte is a synchronization value that must always be 255. Byte 2 is the servo number , and it can be 0-254. Byte 3 is the position to which you want the servo to move, also 0-254

Isn't that what you need to know?

...R

Robin2:
In this document I found this
Isn’t that what you need to know?

…R

yeah found the docs thx …basicly i want to understand the controlling part of the controller…speed …direction …etc.

i wrote this but stuck on how to control its speed and direction

#include <SoftwareSerial.h>

#define RXPIN 3
#define TXPIN 4

SoftwareSerial pololu(RXPIN, TXPIN);

void setup()
{

pinMode(RXPIN, INPUT);
pinMode(TXPIN, OUTPUT);

Serial.begin(9600);
pololu.begin(40000);
}

void loop()
{
pololu.write(0x80); // Start Byte
pololu.write(0x01); // Device ID
pololu.write(0x04); // Command: 0x04 is set absolute position
pololu.write((byte)1); // Servo number
pololu.write(0x04); // First data byte
pololu.write(0x04); // Second data byte
}

Try 9600 baud for SoftwareSerial - it does not really work at high speeds.

Also, for testing, take the code that is in loop() and put it at the bottom of setup() and leave loop() empty.

The piece I quoted in Reply #3 says that an instruction MUST start with a 255. I don’t see that in your code.

…R

Am working in Pololu mode as i want to have absolute position...

The servo is attached to a winch spool and want to hang weight on it that has to drop 2 meters....The servo needs to turn 5 times in order to release 2 meters of line...that on a certain speed.

I need pololu mode for that right ?

I have no idea what "Pololu mode" is so I can't answer your question. What is it supposed to do?

If you are using a continuous rotation servo then you can only control its speed and direction but not its position.

...R

yeah am using this one

https://www.iprototype.nl/products/robotics/servo-motors/servo-360

iejun: Am working in Pololu mode as i want to have absolute position...

The servo is attached to a winch spool and want to hang weight on it that has to drop 2 meters....The servo needs to turn 5 times in order to release 2 meters of line...that on a certain speed.

I need pololu mode for that right ?

A "continuous rotation servo" is not a servo. Its just a motor with a built-in motor driver. You cannot do position control at all with it.

Your options are open-loop with a stepper motor, or closed loop with an encoder and PID loop driving some sort of motor (perhaps the continuous rotation "servo" you have already).