NFC Reader for Home Assistant with M5Stack ATOM Echo and LEGO

Demo

https://youtu.be/kcqGKI0bAL4

Components

• M5Stack ATOM Echo
• M5Stack Mini RFID Reader/Writer Unit (MFRC522)
• LEGO Question Mark Block: search for "MOC 8887" or "MOC 93671" on Aliexpress.

M5Stack components are also available on Aliexpress & Banggood.

Arduino

• Board: M5Stack-ATOM (Board URL, Manual)
• Libraries:
  • 256dpi/arduino-mqtt
  • m5stack/M5Atom (Tested with version 0.0.8)
  • MFRC522_I2C

How it works

1. Read NFC card.
2. Send card ID to local MQTT server, then sleep for 5 seconds (to prevent sending same card multiple times).
3. Play sound on Atom Echo.
4. Receive card ID in tag_scanned event.
5. Run automation depends on card ID.

How to generate custom sound

1. Prepare a 44100 Hz sample rate, Signed 16-bit PCM WAV file. I used Audacity.
2. Run xxd -i sound.wav sound.c in terminal to generate .C file. I use MacOS so I'm not sure about Windows or Linux. Sorry.