Published July 23, 2017 © GPL3+

Trigger Google Assistant on Pi Using Ultrasonic HC-SR04

Trigger Google Assistant SDK on RPi using ultrasonic sensor HC-SR04 on Raspberry Pi.

IntermediateShowcase (no instructions)30 minutes4,201

Trigger Google Assistant on Pi Using Ultrasonic HC-SR04

Things used in this project

Hardware components

Raspberry Pi 2 Model B

Raspberry Pi 3 Model B

Raspberry Pi Zero Wireless

Raspberry Pi Zero

Ultrasonic Sensor - HC-SR04 (Generic)

Jumper wires (generic)

Software apps and online services

Google Assistant SDK

Story

Background

This project is an extension of the previous project (Custom Wake Word for Google Assistant on Raspberry Pi). The previous project showcased the triggering of Google Assistant on Raspberry Pi using a pushbutton and a custom wake word. This project shows how to trigger google assistant SDK on Pi using an ultrasonic sensor, HC-SR04.

Modified Rasbian Image

I had modified a Raspbian image for the custom wake word to work efficiently which can be found here.

If you are using that image, download the following zip file. It contains all the codes and scripts that are required.

Install the audio drivers.

Get the google assistant up and running ( Should hardly take 10 mins if using Pi3 or about 45 mins is using Pi Zero as most of the installation has been already done. Only Authentication is required).

Wire the ultrasonic sensor to Pi as shown in the schematic.

Start the script to start google assistant and then start the ultrasonic trigger script.

Already using Google Assistant

If your Pi is already running a Google Assistant, then download the following zip file https://goo.gl/HWxo6M.

Extract the contents to any directory.

Wire the ultrasonic sensor to Pi as shown in the schematic.

Move into /home/pi/env/lib/python3.4/site-packages/googlesamples/assistant/grpc folder and replace the existing pushtotalk.py file with the pushtotalk.py given in the zip.

Copy the trigger folder into any directory and update it's location in the HCSR04-Trigger.sh script.

Start the script to start google assistant and then start the ultrasonic trigger script.

Make the gassist-start.sh and HCSR04-Trigger.sh executable and use it to start the Google Assistant and ultrasonic trigger respectively.

Code

HCSR04.py

#Libraries
import RPi.GPIO as GPIO
import time
 
#GPIO Mode (BOARD / BCM)
GPIO.setmode(GPIO.BCM)
 
#set GPIO Pins
GPIO_TRIGGER = 21
GPIO_ECHO = 20
GPIO_GASSIST =17 
#set GPIO direction (IN / OUT)
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)
GPIO.setup(GPIO_GASSIST, GPIO.OUT)
 
def distance():
    # set Trigger to HIGH
    GPIO.output(GPIO_TRIGGER, True)
 
    # set Trigger after 0.01ms to LOW
    time.sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)
 
    StartTime = time.time()
    StopTime = time.time()
 
    # save StartTime
    while GPIO.input(GPIO_ECHO) == 0:
        StartTime = time.time()
 
    # save time of arrival
    while GPIO.input(GPIO_ECHO) == 1:
        StopTime = time.time()
 
    # time difference between start and arrival
    TimeElapsed = StopTime - StartTime
    # multiply with the sonic speed (34300 cm/s)
    # and divide by 2, because there and back
    distance = (TimeElapsed * 34300) / 2
 
    return distance
 
if __name__ == '__main__':
    try:
        while True:
            dist = distance()
            if distance()<10:
                print ("Trigger Detected at %.1f cm" % dist)
                GPIO.output(GPIO_GASSIST, False)
                time.sleep(0.3)
                GPIO.output(GPIO_GASSIST, True)
            else:
                print ("Waiting For Trigger")
                time.sleep(1)
 
        # Reset by pressing CTRL + C
    except KeyboardInterrupt:
        print("Measurement stopped by User")

Credits

Trigger Google Assistant on Pi Using Ultrasonic HC-SR04

Things used in this project

Hardware components

Software apps and online services

Story

Background

Modified Rasbian Image

Already using Google Assistant

Schematics

Wiring diagram

Code

HCSR04.py

Credits

Sid

Comments

Embed the widget on your own site

Trigger Google Assistant on Pi Using Ultrasonic HC-SR04

Trigger Google Assistant on Pi Using Ultrasonic HC-SR04

Things used in this project

Hardware components

Software apps and online services

Story

Background

Modified Rasbian Image

Already using Google Assistant

Schematics

Wiring diagram

Code

HCSR04.py

Credits

Sid

Comments

Related channels and tags