I have talked about servos in the past and enjoy playing with them. I thought it would be a good idea to have a servo interface board for the Blue Bird board. I wanted something that would handle a lot of servos. I saw the Adafruit servo interface board and thought that would be great to be able to control 16 servos. I looked at the board and it uses an LED controller chip to control the servos. This chip interfaces to the microcontroller using I2C. That is perfect. I have that bus down pat and a lot of the boards I have built recently uses I2C. It was a natural fit.
I dug around and found a schematic to the Adafruit servo interface board. The chip it uses is the PCA9685 which contains 16 channels of 12 bit PWMs. The chip is designed to control LEDs but also works for servos. The layout of the board was fairly easy I just had to create a spot for the servo connectors. My boards are so small I thought It would be good if I only handled 8 servos per board so that is what I did.
This is the top of the board. I put in a regulator on the board so that it could handle all the power requirements of the servos. You can see that not all the servo connectors are stuffed. I was excited to test the board so I didn’t complete stuff it.
Here is the bottom of the board you can see the PCA9685 chip which controls all the servos.
The schematic is fairly simple.