optical
2 pages across tutorials, modules, pinouts and guides.
beginnerModuleUpdated
Infrared Speed Sensor
A GK105A slotted optical switch on a TinkerBlock board: an infrared beam across a 5 mm slot, judged by an LM393 comparator. Something in the slot reads HIGH; a clear slot reads LOW and lights a red LED. Put a slotted disc through it and count pulses for rpm, up to about 1,900 a second. VCC must be your board's logic voltage.
beginnerModuleUpdated
Reflective Optical Sensor
A Vishay TCRT5000 on a TinkerBlock board: an infrared emitter that is always on and a phototransistor beside it, both looking out of the front. Infrared coming back pulls SIGNAL down from VCC through 4.7 kΩ, so white paper reads low and black tape or open air reads high. Analog only, best at 2.5 mm, and VCC goes to your board's logic voltage: 3V3, or 5V on an Uno.