Beam a booth code with IR Quest

Every badge has an infrared transmitter and receiver. IR Quest, an App Store app, sends 32-bit NEC codes, shows what it receives, and can replay a remote control it has recorded. This hack turns one badge into a "booth beacon" that sends a code over and over, and has a second badge pick it up.

• Difficulty: intermediate, about 30 minutes

• You need: two badges with the IR parts fitted (TSOP38238 receiver on GPIO 18, IR LED driven by a 2N2222 from GPIO 2; see HARDWARE.md), Wi-Fi on the badges for the App Store, and oreo-cli. A TV remote is handy for testing.

Be aware: receiving is not reliable yet#

Sending works. Receiving has an open bug, #48: on the ESP32-S3 the native RMT receiver could fail to start (RMT RX ... failed: ESP_ERR_IN...). The cause found in the code is the receiver's glitch filter, which asked for more than the ESP32-S3 allows (ESP_ERR_INVALID_ARG); firmware with the fix still has to be confirmed on a badge. When the native receiver fails, the driver (oreoWare/ir.py) falls back to timing edges with a pin interrupt, which works but is less exact. IR Quest shows which receiver is running on its DIAG tab, with the complete error. If yours shows one, run the self-test below and add its output to #48; that is a useful contribution in itself.

oreo run tools/ir_selftest.py      # from an OreoOS checkout; ends in "IR48 RESULT"

Despite its store description, IR Quest does not keep or trade tokens yet: it sends, receives and shows codes. Token trading is an app still to be written.

1. Install IR Quest on both badges#

oreo apps install quest

or open App Store on the badge.

2. Check the receiver#

Open IR Quest. It starts on the FOCUS tab, which shows the latest code it decoded in large hex, the protocol and the pulse count. Point a TV remote at the badge and press a button: an NEC remote shows its code, other remotes show as a raw recording.

Press B to cycle the tabs: FOCUS, BEACON, SEND, DIAG. On DIAG, the backend reads native RMT or pin IRQ (fallback), with the RMT channel, DMA, glitch filter, driver state and the full error text if the native receiver failed (UP/DOWN scroll it). A restarts the receiver there, and RIGHT turns on a serial log of every receiver step, which oreo logs shows as [ir] lines.

3. Send a code from the other badge#

On the second badge, open IR Quest and go to SEND:

• UP / DOWN pick what to send: the last recording, or one of the built-in codes (Booth A = 0xCAFEBABE, Booth B = 0xDEADBEEF, Booth C, Booth D, Ping, Pong);

• LEFT / RIGHT pick the carrier: 38, 40 or 56 kHz (the receiver is a 38 kHz part, so keep 38 kHz);

• A fires.

Hold the badges a short distance apart with the IR parts facing each other. The first badge's BEACON tab counts every frame since the app opened and lists the last six.

4. Make a beacon that keeps sending#

For a booth, a badge can send a code every second without anyone pressing A. Save this as beacon.py on your computer:

import time
from oreoWare import ir

CODE = 0xCAFEBABE      # Booth A; any 32-bit value

while True:
    ir.transmit_nec(CODE, carrier_hz=38000)
    time.sleep(1)

and run it on the beacon badge:

oreo run beacon.py

oreo run pauses OreoOS while the script runs and streams its output, so the beacon badge stays plugged into the computer running oreo. Ctrl-C stops it and OreoOS starts again. Visitors with IR Quest open on BEACON see CAFEBABE arrive once a second.

To add your own named codes to the SEND list, edit CODES at the top of apps_market/quest/src/app.py.

Ideas from here#

• A real token game: give each booth a code, and have an app remember which codes it has seen with oreoOS.state. Propose it with the app form.

• Help close #48: its acceptance criteria list what has to be tested.