M5Stack X 16ch Servo Driver PCA9685

2018/09/23
16:16

M5Stack X 16ch Servo Driver PCA9685

Hello everyone! I’m RoboTakao.

Previously I posted an article about using PCA 9685 16 channel PWM servo driver with Arduino.

This time I tried using PCA 9685 with M5Stack.

Connection

PCA9685
+5V　　Battery +
OE　　　 N/A
SCL　　　M5Stack SCL (22pin)
SDA　　　M5Stack SDA (21pin)
GND　　 M5Stack GND and Battery -
VCC　　　M5Stack 3.3V (or 5V)

Use with M5Stack
This time I will try using Arduino library of comparable product of Akizuki.

Instruction manual
PCA9685 Datasheet
Arduino library

Download the library and load it with Arduino IDE.
Sketch → Include Library → Install ZIP format libraries

You can now open a sample sketch from the example sketch.

Description of the sketch
I changed a bit from the sample.
First of all, the sample uses two PCA9685, but since this time it is one, the second part is deleted.
In the sample, the minimum pulse width 150 and the maximum pulse width 600 are set at a 60 Hz cycle as a general servo setting, but as I wrote in the previous post, it is beyond the pulse width range of Micro 2BB MG of GWS used this time I changed it because I understood it when I saw the oscilloscope. (We do not know the unit of minimum and maximum pulse width well)

PWM frequency　60　→　50
Min pulse width　150
Max pulse width　600　→　500

I changed the angle slightly.

This sample sketch rotates 180 degrees from zero degrees in increments of 10 degrees and returns to 180 degrees when it becomes 0.

Include M5Stack.h when using with M5Stack

It's super easy.

Operation check

I was able to confirm that the servo moves as expected.

Sketch


#include 
#include 
#include  

PCA9685 pwm = PCA9685(0x40);

#define SERVOMIN 150            //Min pulse width (GWS Micro2BBMG)
#define SERVOMAX 500            //Max pulse width (GWS Micro2BBMG)

void setup() {
 pwm.begin();
 pwm.setPWMFreq(50);
}

int n=0;

void loop() {
  for(int i=0; i<16; i++)
      servo_write(i,n);
  n=n+10;
  if(n>=180)n=0;
  delay(500);  
}

void servo_write(int ch, int ang){
  ang = map(ang, 0, 180, SERVOMIN, SERVOMAX);
  pwm.setPWM(ch, 0, ang);
}