Looking for practical Arduino projects? This guide shows how to control a relay from your smartphone using an Arduino Uno — either via Bluetooth or Wi-Fi.

This Arduino-based Pomodoro timer project also uses this 25-minute cycle. Once you push the button to start the timer, it will run for 25 minutes, display a count-up timer and a "Study time!" ...

The project does require a Raspberry Pi and an Arduino, priced at about $35 and $20, respectively, bringing the total cost to an estimated $120. This project is also highly customizable.

While lacking infrared (IR) compatibility, the remote excels in smart home integration, controlling devices like lights, thermostats, and air conditioners, with a total cost of $20–$30.