In this post, we will be learning about connect 4 Channel relay board to Raspberry Pi. If you haven't done the RPi setup then please read Raspberry Pi – Introduction and Setup.
What is a relay? A relay is an Electrical Switch which is used to open or close a circuit with an electromechanical relay or electronically. It is generally used to switch lower current. It changes their states when energies, from No( Normally Open) to Close or from NC ( Normally Close) to Open.
We will need following things: 1. Raspberry Pi (I am using RPi 3 Model B) 2. Jumper Wires 3. Relay Board (I am using 4 Channel relay board) 4. Batteries 5. LED Light Lamp (You can take any LED strip. I just fetched out my LED light lamp's strip.)
Connecting Relay board to RPi: 4 Channel relay has 6 lines. GND, VNC, IN1, IN2, IN3, IN4
Note: If you have 2 or 8 channel relay. VNC and GND will be same but counts of INput pins will be different.
Pin Configuration: GND goes to RPi's Ground VNC goes to RPI's 5V IN1, IN2, IN3, IN4 goes to RPi's GPIO pins.
I have only one lamplight. I am attaching it to the first channel.
Are all devices connected?
Coding Part: I created 3 programs for our demo. 1. TunrOn.py: It will be used for turn on the light. (Turning on one channel) 2. TunrOff.py: It will be used for turn off the light. (Turning off one channel) 3. BlinkAll.py: It will be used for turn on and off all the channels.
See code on GitHub.
Get some GPIO programming knowledge here.
Now save all these 3 files on RPi. Now run these files one by one using a terminal (cmd): python TurnOn.py python TunrOff.py python BlinkAll.py
Originally posted here..