Arduino JSON API

A WiFi-enabled Arduino web server that exposes a JSON API for controlling digital pins over HTTP. Originally built for remote control of a door buzzer.

Requirements

• Arduino board with WiFi Shield 101
• ArduinoJson library (v5)
• WiFi101 library

Setup

1. Open arduino-json-api.ino in the Arduino IDE
2. Update ssid and pass with your WiFi credentials
3. Adjust validPins[] if needed (some pins are reserved for the WiFi shield)
4. Upload to your board

The serial monitor (9600 baud) will display the board's IP address once connected.

API

All endpoints use HTTP GET and return JSON responses.

GET /STATE/<pin>

Read the current state of a pin.

GET /STATE/2

{"status":"ok","action":"STATE","data":[{"pin":2,"value":0}]}

GET /STATE

Read the state of all valid pins.

GET /STATE

{"status":"ok","action":"STATE","data":[{"pin":1,"value":0},{"pin":2,"value":1},...]}

GET /ON/<pin>

Set a pin HIGH.

GET /ON/2

{"status":"ok","action":"ON","data":[{"pin":2,"value":1}]}

GET /OFF/<pin>

Set a pin LOW.

GET /OFF/2

{"status":"ok","action":"OFF","data":[{"pin":2,"value":0}]}

GET /BUZZ/<pin>

Set a pin HIGH for 5 seconds, then automatically turn it LOW. The response is returned immediately (non-blocking).

GET /BUZZ/2

{"status":"ok","action":"BUZZ","data":[{"pin":2,"value":1}]}

Error Response

Invalid actions, missing pins, or disallowed pins return a 400 status:

{"status":"error"}

Valid Pins

By default, pins 1, 2, 3, 4, 6, 8, 9, 10, 11, 12, 13 are available. Pins 0, 5, and 7 are reserved for the WiFi shield. Edit validPins[] to change this.