[PYTHON] [Raspberry Pi] Store the timestamp in the Firebase Realtime Database when the motion sensor detects it.

Introduction

This article is Chapter 3 of a four-chapter article.

1. We made a system that "not only" watches over elderly houses by making full use of IoT [SORACOM Summer Challenge 2020]
2. Send a push message to the LINE Bot when the LTE-M Button is pressed [SORACOM]
3. [Raspberry Pi] Store the timestamp in the Firebase Realtime Database when it is detected by the motion sensor: arrow_backward: Now here
4. Link SORACOM with home appliances and LINE Bot [Python / Flask / Raspberry Pi] ** All sources released **

Trigger

I want to notify the LINE Bot of the time when the motion sensor responded and the number of times it responded within an hour. You can run SQL locally, but I thought it would be easier to store it in a cloud database because the Raspberry Pi with a motion sensor and the Raspberry Pi used as a server for LINE Bot are separate, so I used the standard Firebase.

Connecting Raspberry Pi and motion sensor

What I used

--Raspberry Pi 3 Model A + (OK if it is higher than this) --Human sensor module --Jumper wire (female-female)

I used the motion sensor from this manufacturer.

Connect

[Raspberry Pi] How to use and use the self-made motion sensor was used as it is. Be careful of GPIO connection mistakes (I made the mistake of mistakenly pinning pin 12 and Ground).

Firebase I referred to [python] How to get started with Firebase Realtime Database.

Package installation

Install firebase-admin on Raspberry Pi with the following command

$ pip install firebase-admin

Database creation and rule changes

Create a Database from the Firebase console. There are Cloud Firestore and Realtime Database, but please note that this time it is ** Realtime Database **. Change the rules as follows:

• Since it is for testing, please set appropriate rules when actually operating it.

Also, go to Set Project> Service Account> Firebase Admin SDK from the gear on the right side of" Project Overview ", select Python to copy, and click Generate New Private Key. , Save the downloaded private key to Raspeye.

Cooperation between motion sensor and Database

Below is the code

firebase.py

import firebase_admin
from firebase_admin import credentials
from firebase_admin import db
from datetime import datetime
import time
import RPi.GPIO as GPIO

cred = credentials.Certificate("<Downloaded private key>.json")
firebase_admin.initialize_app(cred, {
    'databaseURL': 'https://<databaseURL>.firebaseio.com/'
})

ref = db.reference('data')

INTERVAL = 3
SLEEPTIME = 20
GPIO_PIN = 18

GPIO.setmode(GPIO.BCM)
GPIO.setup(GPIO_PIN, GPIO.IN)

while True:
    if(GPIO.input(GPIO_PIN) == GPIO.HIGH):
        print(datetime.now().strftime('%Y/%m/%d %H:%M:%S'))
        new_data_ref = ref.push()
        new_data_ref.set({
            'timestamp': {'.sv': 'timestamp'}
        })
        time.sleep(SLEEPTIME)
    else:
        print(GPIO.input(GPIO_PIN))
        time.sleep(INTERVAL)

When it is detected, push it to Database with timestamp. A unique ID is generated by pushing. Apparently the ID is also in chronological order.

About registration of timestamp

It is also Issue here, but it seems that there is a habit of registering timestamps from Python's firebase-admin module. I hope you find the 'timestamp': {'.sv':'timestamp'} above helpful.

demonstration

In this way, when detected, it is written to the Realtime Database.

UNIX time 1597307961996 is 2020/08/13 17:39:21 so it's perfect.

Summary

That's all for storing the reaction time of the motion sensor in the Firebase Realtime Database. Next, get that data from another Raspberry Pi.