[Gardner] put together a simple and cheap solution ... The project is aimed at Arduino-based circuits, but any chip with an ADC will work. The 555 timer is used as a free running oscillator.

[Cody] decided to go with a simple 555 timer circuit. Being a business card, [Cody] kept the circuit very simple; it’s just a 555, phototransistor, and a few SMD LEDs. When a 9 Volt battery is ...

Our Circuit Design Calculators for Engineers and Students are free-to-use tools that help you quickly determine key parameters ...