My arduino mega + ethernet shield only works when i upload the sketch and leave it attached to the pc.
If my pc is attached to the arduino i can control everthing with the app, but when i disconnect the pc everythin stops working.
I have the same problem. The Sparkfun Thing Dev works fine with Blynk as long it is connected to pc (right after upload or when just reconnecting to pc). If using any other power source afterwards, eg the usb charger output, battery 5v on VIN etc, it does not seem to start up and no connection to Blynk app. If I only connect the usb to the pc, it works again even by only connecting to pc, No need to upload again.I am using the joystick controller merged to VIN1 to control two motors using an additional motor control hw.
Please open a new thread for this… This one is 6+ months old and you clearly have a different issue as this post was resolved with external power. Please post your code as per @Jamin’s instructions in your new thread. Thank you.