Building simple IOT pipeline for transit environmental testing with Node.js

Transit innovation isn’t just theory — developers can prototype environmental testing systems today. Here’s a quick walkthrough:

Step 1: Publish Sensor Data
Use an ESP32 + MQ-135 air quality sensor to push readings via MQTT:

cpp
int airQuality = analogRead(34);
char msg[50];
sprintf(msg, "AirQuality:%d", airQuality);
client.publish("transit/air", msg);
Step 2: Subscribe with Node.js
Listen for sensor data in real time:

js
const mqtt = require('mqtt');
const client = mqtt.connect('mqtt://localhost:1883');

client.on('connect', () => {
client.subscribe('transit/air');
});

client.on('message', (topic, message) => {
console.log(Received ${topic}: ${message.toString()});
});
Step 3: Visualize
Pipe readings into MongoDB or InfluxDB, then connect Grafana/Kibana for dashboards.