• Raspberry Pi Model 4 Raspberry Pi 4
• x2 Jumper Wires (Length will vary based on needs) Jumper Wires
• Enclosed High-power Power Relay Power Relay

• Cut the male end of the wire jumper off and then strip the wire to leave around 1/8“ inch wire exposed
• Pull out green power input module from power relay box
• Unscrew wire clamp screws on the power input module
• Place striped end of jumper wire into the power input on the module (one to negative, one to positive)
• Screw down wire clamp screws
• Connect the wires to appropriate locations on the Raspberry Pi GPIO pin board (more explanation given below)
• Plug power supply for the raspberry pi into the Always On outlet on the power relay box
• Plug appliances that you want to control into the Normally Off outlet on the power relay box
• Plug power relay into an appropriate outlet

In order to control the power relay box it is necessary that code is written on the Raspberry Pi to make these changes to the power relay box. The example that is provided is in Python which requires that the library rpi.gpio be installed in order to gain control over the GPIO pins on the Raspberry Pi. Step by step examples will be given below to download the library, write code for controlling relay box, and knowing what pins to connect jumper cables to.

• Open terminal
• type sudo apt-get install RPi.GPIO
• installation complete

Example of code written in python
Below is both a full example of the code and a break down of what everything does

Full Example

import RPi.GPIO as GPIO 
import time 
import sys  

GPIO.setmode(GPIO.BOARD)
power_choice = str(sys.argv[1]) 
pin_number = #

if power_choice == 'on':
  GPIO.setup(pin_number, GPIO.OUT) 
  GPIO.output(pin_number, GPIO.HIGH)
  
  While True: 
    time.sleep(1) 
    exit() 
elif power_choice == 'off': 
  GPIO.setup(pin_number, GPIO.OUT) 
  GPIO.output(pin_number, GPIO.LOW) 
 
  while True: 
    time.sleep(1) 
    exit()
    
GPIO.cleanup()

Breakdown

Importing of appropriate libraries into python

import RPi.GPIO as GPIO 
import time 
import sys 

This sets the way that the GPIO Pins will be recognized by the code

GPIO.setmode(GPIO.BOARD)

This allows for user input to tell the code what to do (turn power on/off)

power_choice = str(sys.argv[1]) 

The # should be replaced by an appropriate integer corresponding to the gpio pin picked

pin_number = #

If the input from user specifies on then the code performs as follows

if power_choice == 'on':

This specifies that for a given pin number it will change the output of that pin

GPIO.setup(pin_number, GPIO.OUT) 
 

This sets that pin to be powered on which when power is provided to the relay it switches to on

GPIO.output(pin_number, GPIO.HIGH) 
 

This is code that needs to be added in order for the code to stop after the command is performed

While True: 
  time.sleep(1) 
  exit() 
    

Same thing happens here but this is now just for the turning power off command

elif power_choice == 'off': 
  GPIO.setup(pin_number, GPIO.OUT) 
 
  GPIO.output(pin_number, GPIO.LOW) 
 
  while True: 
    time.sleep(1) 
    exit() 
    

This must be added in order for the pins to not take on multiple arguments from later commands that might be sent

GPIO.cleanup()