Help, my Arduino is dying!

The Arduino/Raspberry Pi combo I’m using for my pizza oven failed completely last weekend, just in time for the biggest event the oven’s had!

We had a party Saturday night, so I lit the oven about lunch time Saturday and cooked a couple of pork bellies, then made pizzas when people arrived for tea. So the oven was fired for 8 hours or so straight. I would have loved to see how the temperature travelled through the walls being fired for that long. But it wasn’t to be.

I am powering the Arduino through a USB connection from the Raspberry Pi, which is I think a mistake. Still, it’s been fine until now. The whole thing is powered by a 12 volt power supply inside, feeding through the spare wires in the ethernet cable, which is fairly long. From the cable it goes through a cheap 12v -> 5v (USB) power converter into the Raspberry Pi, which has a USB connection that powers the Arduino, and lets the Pi pull temperature readings from the Arduinos thermocouple shield. It’s worked fine for over 12 months!

But now if I power the Pi up itself it works fine, but when I plug the Arduino in and initialise the serial the whole thing dies.

I have been wanting to build a decent 12v -> 5v power supply for a while, and power both devices directly from that. Or even better, find a thermocouple interface for the Pi that handles 8 thermocouples so I can get rid of the Arduino altogether.

I guess now that this is happened I finally have the incentive to built that power supply, or two of them, so I can use one in my car as well.