Can an ordinary “disco party” consumer strobe lights that have a variable speed operate up to 15 Hz?
No, most are only promising up to 10Hz.
Would it be simple to custom build a circuit to do this? Say a 555 driving a power mosfet driving an array of 12 volt LEDs?
I think you’re barking up the right tree. The trickiest part is the power relay (power mosfet), which converts the control signal into a power switch for the (relatively) high power LEDs (as I’m sure you understand). Unfortunately I don’t know how to apply them.
However, rather than using a 555 timer, I’d consider using something like an Arduino (hobbyist microcontroller), which would make it very easy to configure and/or control in different ways (like, over 802.11 using a simple mobile app). But for a simple constant-rate or switch-controllable timer, a 555 is the time-honored solution. You could always start with a 555 on a breadboard and replace it with an Arduino if you wanted more control options later.
Two nice things about Arduinos is that there’s a huge body of available software modules for them, and they come in lots of flavors with different peripherals (including 802.11 wifi, IIRC). Who knows, maybe there’s even one with built-in power relays.
I bet there are also power relay IC’s, which would be MOSFETs with all “care & feeding” circuitry inside, expecting only power, ground, and TTL level control signal inputs, which would simplify things considerably. Hopefully someone who knows anything about this stuff can mention a part name or good google search phrase.
Of course, you’ll also need a power supply, with control signal voltages and whatever the LEDs require. I’m just guessing, but I bet you’d want to control the LED power circuits directly, rather than switching the AC feed to an integrated lighting device. But I could be all wet there! My guess is it would depend on the properties of the LED device’s power supply; I doubt that most are designed expecting the power feed to duty-cycle.
I do indeed want to control the DC to the LEDs. I was thinking about either just a commercial 12 volt “wall wart” or just a 23A battery, as to not try to reinvent the wheel.
if you look up “LED Stroboscope” you’ll find some handheld units that can go way above 15 Hz. we have a Hoto ESL-200 we use at work to watch how speaker cones act at various frequencies.
I passed on the idea of using an Arduino because I know absolutely nothing about computer programming. How do I make sure I’m not exceeding the 600mW power rating of the 555? I know a string of a some 60ma LEDs and the resistor consume 500-600 mW, is this the number you use that you can’t go over?
No. A common explanation is that disco lights are more likely to cause epileptic fits above 10, but I’ve seen no actual data to support that.
Don’t try to drive the LEDs directly off of the 555.
Get a logic-level N-Channel FET, and have the 555 drive that. That will give you essentially unlimited power (I’ve driven FETs that can handle 185A of current).
I got the basic circuit working (555 driving a 4024 driving a 2N2222) with a couple of standard LEDs. I want to expand it now with a high powered “star” emitter. To not invent the wheel, there are “buck pucks” designed to drive a high powered LED with constant current. Some of them have an input for PWM dimming. Can I connect the output of a ripple counter directly to that, or conceptually do I want to switch the whole driver with a high powered FET or Darlington?
The PWM input should do exactly what you want.