Plex allows easy ... Arduino UNO board (the most expensive of the components at around $27) and uses only two other main components: an ultrasonic sensor and a servo, totaling about $40. This DIY ...

From DIY 3D printers to FPV drones, there's a lot you could do with your Arduino ... temperature sensor. Likewise, ultrasonic and IR modules are indispensable for robotics projects.

I recently had to build an infrared close proximity sensor ... from the Arduino UNO, the circuit consists of two more primal parts – an infrared emitter and an infrared receiver, which are as follows.