My team and I are creating a project where a sensor board is controlled by two Arduino Nano's, connected using a UART daisy chain. Whenever the board is turned on using a USB connection, the Arduino's and their sensor function normally. But when the 12v source is added, the programmer (or something else inside of the Arduino) of the Nano breaks. We are powering 16 leds and 16 tcrt5000's with these two Arduino's.
My questions are:
- What causes these Arduino Nano's to fry?
- If it's a short circuit, how do we keep it from frying again?
First of all, I'd like to add something: the two nano's have their own regulators. If I take out one of the two nano's and plug in the source, it runs fine. The LEDs and the Sensors work normally. If I add the second one, it breaks down.
To be specific of the burned down Nano's: After plugging in both nano's and plugging in the source, the two nano's were not controlling the LEDs. After removing the power, getting burned by the hot regulator and hot pins from the Atmel, and plugging it into my laptop, I couldn't get the code to upload again because of a "Programmer not responding" Error. It seems like something inside the programmer got fried. I just don't understand how.