Controlling relay via Telegram using Maker Pi Pico and CircuitPython.

code.py

"""
  Controlling relay via Telegram using Maker Pi Pico and CircuitPython.
  
  Items:
  - Maker Pi Pico
    https://my.cytron.io/p-maker-pi-pico
  - ESP8266 ESP-01 WiFi Module
    https://my.cytron.io/p-esp-01-wifi-serial-transceiver-module-esp8266
  - Grove - Relay
    https://my.cytron.io/p-grove-relay
  - USB Micro B Cable
    https://my.cytron.io/p-usb-micro-b-cable
  
  Libraries required from bundle (https://circuitpython.org/libraries):
  - adafruit_espatcontrol
  - adafruit_requests.mpy
  - simpleio.mpy
  
  References:
  - https://core.telegram.org/bots/api
  - https://github.com/shurillu/CTBot
  
  Last update: 27 Dec 2021
"""

import time
import board
import digitalio
import simpleio
import busio

import adafruit_requests as requests
import adafruit_espatcontrol.adafruit_espatcontrol_socket as socket
from adafruit_espatcontrol import adafruit_espatcontrol
import json

# Get wifi details and more from a secrets.py file
try:
    from secrets import secrets
except ImportError:
    print("All secret keys are kept in secrets.py, please add them there!")
    raise

# Telegram API url.
API_URL = "https://api.telegram.org/bot" + secrets["telegram_bot_token"]

NOTE_G4 = 392
NOTE_C5 = 523
buzzer = board.GP18

relay = digitalio.DigitalInOut(board.GP3)
relay.direction = digitalio.Direction.OUTPUT

# Initialize UART connection to the ESP8266 WiFi Module.
RX = board.GP17
TX = board.GP16
uart = busio.UART(TX, RX, receiver_buffer_size=2048)  # Use large buffer as we're not using hardware flow control.

esp = adafruit_espatcontrol.ESP_ATcontrol(uart, 115200, debug=False)
requests.set_socket(socket, esp)

print("\nResetting ESP module")
esp.soft_reset()

def init_bot():
    get_url = API_URL
    get_url += "/getMe"
    r = requests.get(get_url)
    return r.json()['ok']

first_read = True
update_id = 0
def read_message():
    global first_read
    global update_id
    
    get_url = API_URL
    get_url += "/getUpdates?limit=1&allowed_updates=[\"message\",\"callback_query\"]"
    if first_read == False:
        get_url += "&offset={}".format(update_id)

    r = requests.get(get_url)
    #print(r.json())
    
    try:
        update_id = r.json()['result'][0]['update_id']
        message = r.json()['result'][0]['message']['text']
        chat_id = r.json()['result'][0]['message']['chat']['id']

        #print("Update ID: {}".format(update_id))
        print("Chat ID: {}\tMessage: {}".format(chat_id, message))

        first_read = False
        update_id += 1
        simpleio.tone(buzzer, NOTE_G4, duration=0.1)
        simpleio.tone(buzzer, NOTE_C5, duration=0.1)
        
        return chat_id, message

    except (IndexError) as e:
        #print("No new message")
        return False, False

def send_message(chat_id, message):
    get_url = API_URL
    get_url += "/sendMessage?chat_id={}&text={}".format(chat_id, message)
    r = requests.get(get_url)
    #print(r.json())

print("Connecting to a network...")
esp.connect(secrets)

if init_bot() == False:
    print("Telegram bot failed.")
else:
    print("Telegram bot ready!\n")
    simpleio.tone(buzzer, NOTE_C5, duration=0.1)

    while True:
        try:
            while not esp.is_connected:
                print("Reconnecting...")
                esp.connect(secrets)
            
            chat_id, message_in = read_message()
            if message_in == "/start":
                send_message(chat_id, "Welcome to Telegram Bot!")
            elif message_in == "RELAY ON":
                relay.value = True
                send_message(chat_id, "Relay is activated.")
            elif message_in == "RELAY OFF":
                relay.value = False
                send_message(chat_id, "Relay is deactivated.")
            else:
                send_message(chat_id, "Command is not available.")
            
        except (ValueError, RuntimeError, adafruit_espatcontrol.OKError) as e:
            #print("Failed, retrying\n", e)
            continue

secrets.py

# Secret Keys.

secrets = {
    "ssid"                     : "my_wifi_ssid",
    "password"                 : "my_wifi_password",
    "telegram_bot_token"       : "my_telegram_bot_token",
    "telegram_chat_id"         : "my_telegram_chat_id",
}