Output Devices

Group work this week is to measure the power consumption of an output device

MEASURING

We have decided to measure Marta's charlieplexing board. It is a charlieplex of 12 through-hole white leds controlled by an ATtiny44. The LEDS start to light up when pressing a button, with 3 different visual patterns: one by one, one by one faster, and all at the same time.

We connected the board to a DC power supply. We set with a voltage of 5.00V and a maximum current of 100mA. And we started the We got the following results

That is, the power consumption is 0.1W ( that can be easily calculated as P=I*V = 5*0.020 = 0.1W). The current, as it can be seen from the pic, varies from 0.20mA to 0.24mA). This makes sense, as with charlieplexing, just one LED is on at a time, and the standard current for each LED is 20mA.