Hi all, I teach a Bioinstrumentation course for middle school students in the winter as a part of Purdue GERI (Gifted Education Resource Institute). In this course, I introduce students to basics of circuits and how we use circuits in Biomedical Engineering. I’ve found that a nightlight is a good introductory circuit for students learning about electronics. It includes a few basic components like resistors and LEDs. It also includes a more intermediate component, namely the operational amplifier and a useful sensor, namely a photoresistor. The mechanism of the circuit shows students how we can use circuits to interact with the outside world and produce some sort of output. In this case, the nightlight turns on when ambient light levels decrease and turns off when ambient light levels increase. Everyone loves seeing the LEDs turn on and off automatically. I told parents that I would post the various lessons online (and I’m a few months behind o_O) so here I go with the first one! Hope you enjoy my Instructable for the GoodNightLight.”