I'm playing around with this PCA9685 16-channel PWM driver from Adafruit.
I used one before in my FlatCat project, and I'd like to use one again in the new little robot I'm building which uses a QT-Py S3.
Power
I want to run the whole robot from a single battery pack, so I need to figure out how to do that right. FlatCat needed two separate power supplies - a set of four AAA cells for the servos and a separate USB Phone charger for the Arduino.
The image above shows the PCA9685 connected to an Arduino UNO - and it appears to be running the servos and the UNO of the same power from the V+ terminal, with power for the UNO being provided through the VCC terminal.
I have connected my 4.5v battery pack to the PCA9685 for a test
I have 4.5v across the screw terminals, and between GND and V+ on the edge, but nothing on the VCC - so there's no power regulator on the PCS9685, so I can't use that pin to send power out from the PCS9685.
Here is an option using the built-in STEMMA connector on the QT-PY S3.
This runs a V+ power output from the PCS9685 to the QT-PY's +5V pin - or, even better, to the BAT pin on the rear of the QT-PY, which DOES have a voltage regulator.
The STEMMA interface cable includes GND, SCL, SDA and VCC, which can be connected to the corresponding terminals on the PCS9685.So this OUGHT to work.
What I don't have is the STEMMA cable - So I could make the connection like this instead.
PCB
