The device is for my "Bubba Keg", a creation made for a few friends. Essentially it is a control system for the 70oz Bubba Keg insulated mugs. It uses an ultrasonic sensor in the lid to determine quantity and a PTC thermistor in the cup to determine content temperature. For the old design I used a custom PCB that joined an Arduino Nano and 1.8" TFT display. It ran off a 9v battery and was housed in a generic enclosure. it was far more bulky than I wanted it to be. That is why I went for a SoC solution.
The display has gauges for quantity, temperature and voltage. The display also shows you calculated L/Hr consumption rate and time to empty.
Programming the ATMEGA without USB support was the challenge, but I found some tutorials on using another arduino (UNO) as an ISP (In Service Programmer). I wired the two together and used the Arduino IDE to program the chip. I was very pleased to see it working! Not having the bootloader on the chip means it starts up lightning fast and has more room for programming space. I chose 8MHz to conserve power as it was more important than performance.
Next step will be to custom design and 3D print a nice compact enclosure for it and test fit it on a mug!