Building a remote light switch using RaspberryPi

February 6, 2019

Endre Toth

Endre Toth

What kind of cat loves raspberry?

raspberry

…actually I know one, who is a huge fan of Raspberry Pi…it’s CHOCOLATE from the ConfigCat team 🙂

Ingredients:

  • Raspberry Pi 2/3 with:
  • python3
  • ConfigCat python SDK
  • (‘GPIO Zero’ integration to any hardware) - optional
  • ConfigCat subscription (free plan is enough :))

Step 0. – Prepare the device to run your code

I use my board with Raspbian OS but you can use any distribution. I prefer it because it (usually :)) contains all necessary components for my pet projects. Read more about Raspberry Pi OS installation here.

install ConfigCat

Install ConfigCat SDK with pip:

sudo pip3 install configcat-client

install gpiozero libs

By default the Raspbian desktop image contains the GPIO Zero package. On a different OS, you’ll have to use PIP:

sudo pip3 install gpiozero

Step 1. – Set up your ConfigCat project

Log in to ConfigCat

  1. Create a feature flag
  2. Copy your SDK Key from the SDK Key tab.

Step 2. – Code

Create a file (e.g. remoteswitch.py) with your favourite editor (I prefer nano) and implement the following code:

from gpiozero import OutputDevice
import time
import configcatclient

# set GPIO#3 port (you can select any GPIO output port)
relay = OutputDevice(3)

# initialize ConfigCat client to get your setting value
client = configcatclient.create_client_with_manual_poll('YOUR_SDK_KEY')

while True:

        # get the latest value
        client.force_refresh()

        # save into 'my_remoteswitch' variable
        my_remoteswitch = client.get_value('demoswitch', False)

        # for debug purpose only
        print(my_remoteswitch)

        # depend on the value the condition turns on/off the output
        if my_remoteswitch == True:
                relay.on()
        else:
                relay.off()

        time.sleep(5)

pause()

In line 9 you should add your own SDK KEY. This solution uses the ConfigCat SDK’s in manual polling mode. (Read more about polling modes here).

Step 3. – Test

Run your code with the following:

python3 remoteswitch.py

console

Depending on the value of setting the program prints the actual value of your switch on the ConfigCat Dashboard and turns on/off the OutputDevice as well.

Step 4. – Demo

For the demonstration I created a simple circuit.

wire

The components I have used:

  • LED diode to show the switch status
  • one resistor to limit the current (500Ω)
  • two wires to connect to GPIO#3 port and a ground
  • Raspberry Pi to serve power to the LED (you won’t need external power supply)

Step 5. – Further development possibilities

  • Set up a program as a daemon (always run, after reboot)
  • Apply this solution with any wireless power switch on your home
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