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I started with hooking up the PCA9685 board to my Pi 4B and then installing the Adafruit PCA9685 library.

I followed this guide Control Servos using 16 Channel Servo Driver And Raspberry Pi except that I installed the latest adafruit library

I tried different examples I found but the servos don't move.

I get no errors but there's no movement.

When going through a loop

for i in range(180):
    servo.angle = i
    print(servo.angle)

it prints the angle from 0 to 180, but....no moving servos.

What could be wrong? It's the az-delivery PCA9685 board, could there be a problem with that..?

I'm using the AZDelivery SG90 Micro Servo Motor 9G

Also when I execute sudo i2cdetect -y 1 I get

0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: 70 -- -- -- -- -- -- --

That's ok I guess.

Below are the images showing the connections.

pi4B PCA9685

Note: I’m using a 5V supply for the servo motors on the PCA9685 board.

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3
  • We need more information. There are plenty of similar questions. Look at them then edit yours with the needed info.
    – joan
    Commented Aug 22, 2022 at 9:58
  • I made some edits to make my problems more clear
    – Wezy
    Commented Aug 22, 2022 at 13:54
  • Are you using a second power supply for the servos? Also, it would be very useful if you included photos of your equipment.
    – NomadMaker
    Commented Aug 22, 2022 at 15:30

2 Answers 2

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1

The device appears to be wired correctly.

Try running this example code.

http://abyz.me.uk/rpi/pigpio/examples.html#Python_PCA9685_py

Unzip then

sudo pigpiod
python PCA9685.py
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5
  • Thank you for your answer. I tried it, when I ran python PCA9685.py I got an importerr: ,no module pigpio so I used python3 PCA9685.py, that ran without error, but also without movement. I took some time before the cursor came back so I guess it's doing something.
    – Wezy
    Commented Aug 23, 2022 at 7:05
  • Sounds like duff servos or power supply. Try connecting a servo directly to the Pi (5V, ground, plus GPIO). If you connect to GPIO4 (pin 7) give the command pigs s 4 1000 then pigs s 4 2000. It should move if the servo is ok.
    – joan
    Commented Aug 23, 2022 at 7:30
  • when I connect the servo directly to the Pi I can get them to move with those commands, so the servo's are ok.
    – Wezy
    Commented Aug 24, 2022 at 9:09
  • 1
    I suggest you connect one of the PCA9685 PWM outputs to a Pi GPIO set in read mode. Then use piscope or monitor.py to check that a signal is being generated when you run a test. Perhaps the power supply is wrongly connected.
    – joan
    Commented Aug 24, 2022 at 9:38
  • Omg, that was it, the power supply cables where wrongly connected. Now they're moving like they should. Thanks for thinking about it.
    – Wezy
    Commented Aug 24, 2022 at 9:45
0

I guess the problem is you connected 3.3 V [Pi] -> 3.3 V/5 V PCA9685.

You can use 5 V from the Pi or connect an external power source to the V+ pin.

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