Unable to find PCA9685 module when using the I2CScanner library: no servo movement

Question

I am trying to use an Adafruit PCA9685 servo driver module with an ELEGOO Mega 2560 board.

I am supplying the servo driver board with 5 V and tested all the wires to make sure. I tested the servo without the board and it works fine.

enter image description here

I2CScanner code:

#include "I2CScanner.h"
I2CScanner scanner;
void setup() 
{
 Serial.begin(9600);
 while (!Serial) {};
 scanner.Init();
}
void loop() 
{
 scanner.Scan();
 delay(5000);
}

• PMF: What exact board is this? Looks like an Arduino Due, in which case you would be using the wrong pins. Try to use the pins labeled "SCL" and "SDA".
• Blaze48gamer: @PMF the exact board i am using is the elegoo mega 2560 and have put the pins in the "SCL" and "SDA" near the "AREF"
• PMF: I'm not exactly sure about this board, but have you tried the other pins marked "SCL" and "SDA" (Pin 20/21 I think, near the green Led)
• Blaze48gamer: @PMF It should be the exact same as the Arduino Mega 2560, I have tried those pins also the older version "A4" and "A5" pins but it still didn't detect anything. Thx for helping btw.
• jsotola: what is the result when you run the code? ... please copy and paste into your post... no pictures please

Answer 1

The I2C bus needs a set of pull up resistors. When buying assembled I2C devices, the designer may include I2C pull up resistors but not connect them. This is because, according to this sparkfun.com tutorial, you only need about 4.7K Ohms of pull up resistance. Adding multiple I2C boards to the same bus all with their own pull up resistors will lower this resistance and may damage I2C drivers. So, it is up to the end-user to decide which I2C board to connect the pull up resistors on.

• PMF: The breakout manufacturer (Adafruit in this case, I think) would write if that was necessary. But they explicitly state that it already has pullups.