Arduino "embedded device"
Input is slide-potentiometer - continuous scale "analog" voltage from 0V to 5V
Output LED's activated per program - Red to 10% voltage, Yellow 10% to 80% voltage, Green 80% to 100% voltage (100% = 5V).
Trivially simple. On first try with Arduino, own idea try analog input / digital output, a significant step.
Thanks "Tech Jam" of Software Cornwall, where they had an Arduino for me to try and gave me a bit of mentoring.
I have used "C" programming language before, usually used to construct the instructions to an Arduino, which helped.