Worked example: ``two_led_thermo``
==================================

A minimal cuewire rig in two LEDs, one thermistor, and a camera TTL
trigger.  Walks a 105-second phasing protocol while streaming 10 Hz
CSV telemetry to a log file.

Hardware
--------

==============  =====  =====================================
Function        Pin    Notes
==============  =====  =====================================
LED A           D9     series resistor (220 Ω) to GND
LED B           D10    series resistor to GND
Camera TTL      D11    HIGH = recording
NTC thermistor  A0     5 V — 10 kΩ — A0 — NTC — GND
==============  =====  =====================================

The thermistor branch matches a 10 kΩ-at-25 °C, β-3950 NTC bead;
adjust ``THERM_R25`` and ``THERM_BETA`` in
``thermistor.ino`` for other parts.

Protocol
--------

Nine integer commands plus the 1337 handshake:

=============================== =========  ====================================
Method                          Integer    Effect
=============================== =========  ====================================
``rig.comm_test_minimal()``     ``1337``   ``50 1337`` echo
``rig.write_out(True)``         ``100``    start 10 Hz telemetry
``rig.write_out(False)``        ``101``    stop telemetry
``rig.led_a(True)``             ``200``    LED A on
``rig.led_a(False)``            ``201``    LED A off
``rig.led_b(True)``             ``210``    LED B on
``rig.led_b(False)``            ``211``    LED B off
``rig.camera(True)``            ``300``    camera TTL HIGH
``rig.camera(False)``           ``301``    camera TTL LOW
=============================== =========  ====================================

Telemetry frame, one CSV line every 100 ms::

    >clock_s,temp_C,led_a,led_b,cam<

Phase machine
-------------

``run_protocol()`` walks five phases (105 s total):

::

    camera ON
    ├── 30 s   PRE_STIM     both LEDs off
    ├── 15 s   LIGHT_A      A on,  B off
    ├── 15 s   LIGHT_B      A off, B on
    ├── 15 s   LIGHT_AB     A on,  B on
    └── 30 s   POST_STIM    both LEDs off
    camera OFF

Running it
----------

**Path A — Python simulator (zero installs)**:

.. code-block:: python

   from cuewire.examples import TwoLedThermoSimulator, run_protocol
   with TwoLedThermoSimulator() as sim:
       run_protocol(sim.device_path, "two_led_thermo.log")

**Path B — real firmware in simavr**:

.. code-block:: bash

   sudo apt install simavr libsimavr-dev
   arduino-cli compile --fqbn arduino:avr:uno \
       --output-dir /tmp/two_led_thermo_build \
       examples/two_led_thermo/firmware/two_led_thermo
   make -C examples/two_led_thermo/simavr
   ./examples/two_led_thermo/simavr/simrun \
       /tmp/two_led_thermo_build/two_led_thermo.ino.hex &
   python examples/two_led_thermo/run_protocol.py --port /tmp/simavr-uart0

See the full walkthrough in
`examples/two_led_thermo/README.md
<https://github.com/zerotonin/cuewire/blob/master/examples/two_led_thermo/README.md>`_.