Step 1: Sodering the PocketBeagle
Step 2: Connecting the servo and PIR motion sensor to the PocketBeagle
Servo
PIR Motion Sensor
Step3: Downloading the Servo Control Code
Step 4: Copying the Servo Control Code Onto the PocketBeagle
Step 5: Running the Servo Control Code
Step 6: Assembling the Light Switch

Published May 2, 2018 © GPL3+

PocketBeagle Automatic Light Switch

Create an automatic light switch using a simple servo, PocketBeagle board, and Adafruit PIR motion sensor!

BeginnerFull instructions provided3 hours1,825

Things used in this project

Hardware components

Solderless Breadboard Full Size

Female Header 20 Position 2 Row (0.1")

PIR Motion Sensor (generic)

USB-A to Micro-USB Cable

Hitec HS-422 Servo Motor

MicroSD card

BeagleBoard.org PocketBeagle

Story

We all use light switches. It is the only way to turn off and on a light in a room. For those with a busy schedule, sometimes lights forget to be turned off when leaving a room. While there are motion sensor based lighting systems on the market, they are relatively expensive. What if you could create your own motion-activated lighting sequence at home? Well now you can! Using a simple PocketBeagle development board, servo motor, and PIR motion sensor, you can set up your own home-based lighting system that turns on the light when it senses motion, such as entering a room, and switches off the light when there is no motion sensed after a certain period.

Step 1: Sodering the PocketBeagle

Soder the two 2x18 100mil headers onto the PocketBeagle and place on the middle of the breadboard

Cutting the header with the short leads for inner rows (pull out the middle 4 pins and cut in two)

Cutting the headers with long leads for outer rows

Step 2: Connecting the servo and PIR motion sensor to the PocketBeagle

Servo:

1. Connect the red wire on the servo to the 5V power rail connected to Vout on the PocketBeagle

2. Connect the black wire of the servo to the ground power rail on the breadboard

3. Connect the yellow wire to a PWM pin on the PocketBeagle (P2_1)

PIR Motion Sensor:

1. Connect the ground pin on the PIR motion sensor to the ground power rail on the breadboard

2. Connect the VCC pin to the 5V power rail connected to Vout on the PocketBeagle

3. Connect the Out pin to a GPIO pin on the Pocketbeagle (P2_4)

Step3: Downloading the Servo Control Code

Prior to completing the remaining steps, make sure to connect your Pocketbeagle to a CPU using a USB type A to micro USB port.

Downloading the Adafruit_BBIOLibrary

1. Open Cloud9 by entering 192.168.7.2:3000 on your address bar

2. Connect your Pocketbeagle to the internet via a USB connection:

http://ofitselfso.com/BeagleNotes/HowToConnectBeagleboneBlackToTheInternetViaUSB.php

3. Install the Adafruit_BBIO library by typing the commands from the link below into the Cloud9 Bash interface

https://learn.adafruit.com/setting-up-io-python-library-on-beaglebone-black/installation-on-ubuntu

Step 4: Copying the Servo Control Code Onto the PocketBeagle

1. Download the servo control code attached to this project

2. Drag and drop the python code into a folder within the Cloud9 Interface

Step 5: Running the Servo Control Code

1. Type 'ls' into the bash command window to see the contents of your current directory

2. If the servo control code is not in the current directory use the command 'cd' along with the directory pathway for the folder you imported the servo control code into. In my case I would type "cd /ENGI_301_Final_Project/" based on the figure above

3. Type 'ls' again into the bash command window to make sure the servo control code is within your current directory

4. To run the code, type "sudo python Servo_Control.py" in the bash terminal to start the code

5. You should see the following messages below and your Servo begin to move if your code runs successfully

Step 6: Assembling the Light Switch

After setting up the PocketBeagle and running the code to check that the servo motor works with the PIR sensor, we need to extend the linear motor attachment of the Servo. This is done by attaching half of a Popsicle stick to it to allow the motor to hit the switch properly.

Attaching the Setup to the Wall

1. Use command strips or other adhesives to attach the Servo and breadboard to the wall

2. Make sure to attach the servo right next tot he light switch so that the motor attachment lies directly above the light switch when the light is on.

Further Improvements

This project can be further improved by addition of a microphone. By being able to say "OFF" or "ON" to turn the lights on / off will be a cool addition to the project decreasing the need to move to keep the lights on. Additionally a keep on feature could be implemented to keep the Servo in the "ON" position for a desired amount of time after the light switch is flipped. A mechanical assembly to hold the servo in place could also be developed.

Demonstration

A demonstration of the entire setup turning on and off a regular light switch can be found in the attachments to this project.

Code

Servo Control Code Using PIR Motion Sensor

# Import Libraries
import Adafruit_BBIO.PWM as PWM
import Adafruit_BBIO.GPIO as GPIO
import time
# Initial Variables
servo = "P2_1"
pir_value = 0
PIR_PIN = "P2_4" # Pin number connected to PIR sensor output wire.
# Calibrate servo
PWM.start(servo,50,60)
time.sleep (1.0)
PWM.stop(servo)
PWM.cleanup()


# Get PIR Output
# Setup digital input for PIR sensor:
direction = GPIO.setup(PIR_PIN, GPIO.IN)
# Get PIR output from GPIO port
pir = GPIO.input(PIR_PIN)

# Main loop that will run forever:
old_value = pir_value
while True:
    pir_value = GPIO.input(PIR_PIN)
    print("pir_value = {0}".format(pir_value))
    
    if pir_value:
        # PIR is detecting movement!
        # Check if this is the first time movement was
        # detected and print a message
        if not old_value:
        # Rotate the servo CCW 180 degrees
            PWM.start(servo,0,60)
            time.sleep (1.0)
            PWM.stop(servo)
            PWM.cleanup()
            print('Motion detected!')
            
    else:
        # PIR is not detecting movement. Turn off LED.
        # Again check if this is the first time movement
        # stopped and print a message.
        if old_value:
        # Rotate the servo CW 180 degrees
            PWM.start(servo,50,60)
            time.sleep (1.0)
            PWM.stop(servo)
            PWM.cleanup()   
            print('No motion detected')
    old_value = pir_value
    time.sleep(5.0)
    # Press CTRL + C to end program

Credits

Babs Ogunbanwo

1 project • 0 followers

Rice University Student

PocketBeagle Automatic Light Switch