1 Arduino board. Must be provided with a serial port in case the case of communication via the Serial. Must be provided with an Ethernet port or an Ethernet Shield 2 in case the case of communication ...

Connect relays to digital output pins on whatever Arduino via appropriate isolation circuitry, starting at some pin (default 5), sequentially Set the start pin and number of relays at the top of the ...

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.

An RC circuit in series with the coil allows full-current turn-on for reliable relay operation, then reduces the current to save power. Fellow engineer Sanjay R. Chendvankar of Mumbai, India ...