Written by Natesh Narain
on 

Helios Light Controller Rev D

A few months back I re-design my light controller using an ESP32. It worked out pretty good, but not quite ready to use. In the last few weeks I’ve fixed the hardware bugs and added some new functionality.

The new functionality I needed for real usage was:

I didn’t want to have this controller plugged in long term without a cooling solution.

Fixing Hardware Bugs

The old design had an issue where I had a pull-up resistor on one of the strapping pins, causing a bad boot configuration. This was fixed by moving all the IO I used to non-strapping pins.

Temperature sensor and PWM Fan Support

WLED has usermods for temperature sensing and fan control. This requires a DS18B20 temperature sensor.

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Now, there’s a 4.7k resistor here that I originally missed. So in the pictures below you’ll see it fly-wired.

The fan requires a new logic shifter circuit and a pin header.

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The firmware configuration for WLED is the following:

[platformio]
default_envs = esp32dev

[env:esp32dev]
board = esp32dev
platform = ${esp32.platform}
platform_packages = ${esp32.platform_packages}
build_unflags = ${common.build_unflags}
build_flags = ${common.build_flags_esp32}
             -D WLED_RELEASE_NAME=ESP32
             -D USERMOD_DALLASTEMPERATURE
             -D USERMOD_DALLASTEMPERATURE_CELSIUS
             -D USERMOD_PWM_FAN
             -D PWM_PIN=16
             -D TACHO_PIN=17
lib_deps = ${esp32.lib_deps}
monitor_filters = esp32_exception_decoder
board_build.partitions = ${esp32.default_partitions}

Results

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Rev E

As I’ve mentioned above, I missed a resistor. I also realized I should add a break out for I2C and some extra IO.

So the next rev will look something like:

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