QT Py works by usb only while port is open in IDE

[jadle]

QT Py M0 works well while connected to computer usb and the port is connected in arduino IDE. Without IDE open and also with USB battery it does not turn on, but power goes to sensors and out on the 5v pin. Thank you

[dastels]

How do you know it doesn't turn on? Have you tried running the blink sketch? https://learn.adafruit.com/adafruit-qt- ... ixel-blink

My guess is that it's waiting for a serial handshake. Are you setting up Serial in setup() and doing the while (!Serial) wait?

Dave

[jadle]

Solved! You are my hero. I am ashamed to admit I had not tried the blink until now.

Yes it was the (!Serial). I commented out the lines below in the adafruit AHT20 temperature sensor example code to use it as a simple relay controller for greenhouse automation.

Serial.begin(115200);
//while (!Serial)
//delay(10); // will pause Zero, Leonardo, etc until serial console opens
//Serial.println("Adafruit AHT10/AHT20 test!");

Thank you so much for saving the project!

[dastels]

You're welcome.

I see that "problem" quite often.

Dave