Hello,
First time posting, long time reader. I’m down a rabbit hole modfifying a photo light. I need a a shadow projector for a permanent installation. From BLF I learned Lexel 2017 post that a small emitter needed for sharp focus of shadows.
The objective is slightly different from a traditional flashlight. I want a very small, bright, unobstructed LED emitter that projects sharp silhouettes without a focusing lens or reflector.
However the power isn’t really enough. At first I thought I’d modify a Convoy S1 but the battery is going to run out and long term heat management is a problem. I found these Godox ML30 that can run constant at 30 watts. The system is very elegant. Aluminum fins with a 12 volt fan to dissipate heat. But I can’t mod the board for a smaller driver. It uses 14 volts which it converts to 37 volts and .8 amp output. I need a single OSRAM HX so I need to make my own driver system .
What I’ve done so far
The original COB is a Lighten R01-21079-04, rated 37.1V at 0.8A.
My plan is to replace the large COB with an Osram KW CULPM1.TG Boost HX, operating around 3–6A.
After examining the Godox circuit boards, I’ve decided to abandon their electronics entirely. Reverse-engineering the proprietary driver and controls seems unnecessarily complicated.
Proposed new design
I want to use:
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A regulated 12V power supply.
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A compact constant-current buck LED driver.
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The Osram Boost HX emitter.
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The existing Godox heatsink and cooling fan.
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An inexpensive ESP32 microcontroller for fan and temperature monitoring.
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Independent hardware overtemperature shutdown.
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An external aluminum IP-rated enclosure for the electronics.
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A single multicore cable entering the Godox housing through its original power connector opening.
I’m considering two inexpensive drivers:
Option 1 — Mountain Electronics 17mm MTN-MAXlp HP
Availble in high-current configurations up to 5.1A for 3V emitters. It has flashlight-style brightness modes and requires thermal coupling to a metal mounting structure.
Option 2 — DROK 12A CC/CV buck converter
Adjustable current and an LCD readout. Larger than the MTN-MAX, but potentially useful for establishing the optimum LED operating current.
Questions for BLF
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Which driver would you recommend for continuous operation of a single Boost HX from a 12V supply? Is there a better inexpensive alternative?
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Would the MTN-MAX brightness modes introduce objectionable PWM artifacts in photographs?
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Can the driver be installed in an external aluminum enclosure with a few feet of wire running to the emitter?
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Does an ESP32 make sense for monitoring heatsink temperature and managing the fan? What’s a good simple failsafe thermal shutdown arrangement?
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Are there any COBS a folks could recommend?
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Any other driver options that I could use that would integrate the driver, the fan control and the temperature input?
I’m also looking for an extremely inexpensive ($5 or less) single-emitter light to include with the laser-cut cards for home use.
Thanks for any advice. It’s great to be working on this type of project again!
