robot.py

import explorerhat
import subprocess
import signal
import json
import time
import sys
import os

from paho.mqtt import client as mqtt_client

speed = 50

broker = 'localhost'
clientId = 'robot'
topic = clientId + '/action'
username = 'test'
password = 'test'

port = 1883
useWebsocket = False


# Handle incoming messages and take action
def handleMessage(client, userdata, msg):
    message = msg
    print("Received a new message: ")
    print(message.payload)
    print("from topic: ")
    print(message.topic)
    print("--------------\n\n")
    if message.topic == topic:
        payload = json.loads(message.payload)
        if payload['action'] == 'forward':
            explorerhat.motor.forwards(speed)
        if payload['action'] == 'backwards':
            explorerhat.motor.backwards(speed)
        if payload['action'] == 'left':
            explorerhat.motor.one.backwards(speed)
            explorerhat.motor.two.forwards(speed)
        if payload['action'] == 'right':
            explorerhat.motor.one.forwards(speed)
            explorerhat.motor.two.backwards(speed)
        if payload['action'] == 'stop':
            explorerhat.motor.stop()

        time.sleep(0.2)
        explorerhat.motor.stop()

# Init MQTTClient

def connect_mqtt():
    def on_connect(client, userdata, flags, rc):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    client = mqtt_client.Client(client_id)
    client.username_pw_set(username, password)
    client.on_connect = on_connect
    client.connect(broker, port)
    return client

def subscribe(client: mqtt_client):
    def on_message(client, userdata, msg):
        print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")

    client.subscribe(topic)
    client.on_message = handleMessage

def run():
    client = connect_mqtt()
    subscribe(client)
    client.loop_forever()

run()
time.sleep(2)


while True:
    time.sleep(0.2)