Bus Wait Display — Daniele Lin

A small, always-on embedded device that polls ATM Milano's GiroMilano endpoint every five seconds and tells me, right there on my desk, when the next bus is coming.

Milan's ATM publishes real-time arrivals for every stop. The official app is fine; an LCD on your desk showing the next two buses at a glance is better. No phone to unlock, no app to open, no notification to miss.

What the LCD looks like

How it works

The ESP8266 connects to Wi-Fi on boot.
Every timerDelay ms, it issues an HTTPS request to the GiroMilano endpoint for a configured (lineCode, stopCode).
JSON is parsed on-device with ArduinoJson.
The LCD is only touched when a value changes — a small but genuine win for battery life, for display lifetime, and against visible flicker.

Wiring

LCD VCC→3V3 LCD GND→GND LCD SDA→D2 LCD SCL→D1

The I²C LCD is nominally 5 V, but runs fine at 3.3 V in practice — which is exactly what the ESP8266 hands out on its logic pins, so no level shifter needed.

Dependencies

ESP8266WiFi, ESP8266HTTPClient, WiFiClient, ArduinoJson, LiquidCrystal_I2C.

Build

$ git clone https://github.com/lindaniele/bus-wait-display
$ open main.ino in Arduino IDE
$ set SSID, password, lineCode, stopCode
$ select board: "NodeMCU 1.0 (ESP-12E)"
$ Upload

Five seconds is configurable; I keep it at five because the ATM API is generous and because standing at a bus stop staring at an empty display feels worse than it should.

→ Firmware on GitHub