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I would like to build a Stroboscope with the most cost-effective and less time-consuming approach. I would like to be able to control and know the frequency of operation, which should be at least of 50 Hz. I would like it to be able to illuminate an entire room (20 squared meters).

A little bit of context, so far the options I've seen have been:

  • Buy a pre-made one:

Although I've not found any cheap plug-and-play stroboscopes, we may take advantage of "disco" products like this (LED) or this (Xeon).

PROS: Cheap (<10$), fully assembled. CONS: Low max frequency (<15 Hz). Low brightness (LED case).

I do not know if it would be doable to modify the circuitry of these products to make them flash at higher Hz.

There are also some interesting timing lights from the car-industry that could also serve.

PROS: Fully assembled, high frequency operation. CONS: Low power, need for external battery, more expensive.

  • Create your own:

In that case I've seen several interesting schematics online. However, I would like to avoid doing PCBs in favor of a minimal modification of an existing design. It was at this point were I thought that floodlight lamps are cheap yet powerful (50 W for under 20$), and maybe they could be driven by a simple MOSFET controlled by an Arduino. However, I've not been able to find any example of this design in Internet.

Is that really a bad idea? Can the AC to DC transformer (the LED driver), be damaged by high rate switching? Would a large capacitor at the output of the driver help on that?

Thanks,

Seitam
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  • You need to dig in to the LED driver and hopefully find a PWM IC with an enable pin. Problem is you are by now tinkering on the primary side so you are are mains potential. – winny Jul 20 '18 at 12:49
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    A lot of lamps do switch on/off too slowly to be a stroboscope – PlasmaHH Jul 20 '18 at 12:54
  • you're on the right track with a MOSFET, just get a cheap LED COB of whatever wattage you want, and make sure it has no capacitors or active cirtcuitry on it. You can then turn it on and off thousands of times a second (or less) with a small mosfet gate voltage. Should all be under $5 if you have the AVR – dandavis Jul 20 '18 at 17:30

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Use a $28 Mean Well HLG-40-24B LED driver to power a
$4 Bridgelux BXEB-L0280Z-50E1000-C-B3

enter image description here


The HLG (B type only) has a 10V Dim/PWM wire.

You can likely find a cheaper Mean Well knock off.
All you need to do is add a 10V signal from your Arduino.


enter image description here

Misunderstood
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  • Have a look at a [Dimmable mains PSU control](http://lednique.com/power-supplies/dimmable-mains-psu-control/) which I wrote after I'd spent some time figuring out how these worked. The capacitor on the input circuit will, most likely, prevent strobing. – Transistor Jul 20 '18 at 15:33
  • @Transistor I guess that will depend on the value of R1. I understand they recommend a PWM frequency of 100-3kHz. With a pulse width less than 50% it should work okay below 100 Hz. If not then a switched MOSFET on the output should work. – Misunderstood Jul 22 '18 at 09:02