Introduction: ARDUINO 3 Relays Shield (Part-1)
Hey peeps! Here comes my next instructable.
Presenting here 3 channel relay board shield for Arduino to control AC appliances at a time. A Relay is actually a switch which is electrically operated by an electromagnet Relays are useful for triggering AC appliances with a low signal which can be used in home automation systems. The Arduino 3 Relays Shield is a solution for driving high power loads that cannot be controlled by Arduino's digital IO's due to current and voltage limitations of the controller.
Step 1: COMPONENTS REQUIRED
1) SPDT 12v Relay - 3
2) Optocoupler 817 - 3
3) LED - 4
4) BC547 Transistor - 3
5) 2 Pin Terminal Block - 4
6) Resistor 1k - 7
7) IN4007 Diode
9) 12v Adapter
10) Arduino UNO
11) Connecting Wires
Step 2: CIRCUIT DIAGRAM
In this 3 Relays circuit, an optocoupler is used to trigger the NP N transistor which further drives the relay . The Optocoupler will be triggered by an active low signal. In our project 12v relay is used. A 5v or 6v relay can also be used. LED's indicate the status of each relay.
Step 3: DESIGN
I have designed the 3 relays Arduino shield using Eagle CAD Tool which is convenient for me. Below is the board layout. I have also shared Gerber files which has to be sent to the manufacturer for fabricating board.
Step 4: PCB Fabrication
After generating Gerber from Eagle CAD tool I uploaded my design on LIONCIRCUITS where I can get instant DFM feedback after payment. Custom shape image rendering is also good. Highly recommended.
So guys, Stay tuned for the next part of this instructable.