module which we have created above (3.1) has 4 relays. We should set pin number and pin mode for each relay. As an example, look at the figure below! Arduino Uno and 4 Relay Module are connected. If ...

-Pairing with any Arduino/Raspberry Pi Bluetooth accessory -Control a 4 relay module ( Can be upgrade to controle a 16 relay module ). -Test and controle all the ralay module function at once.

Components Required To build an RFID Door lock system, we will need a few essential components. Here is a simple list of what you will need to start. Arduino UNO R3 Development Board RC522 RFID Reader ...