I want to make a Extremely fast & powerful flash for highspeed photography.
--- a "air-gap" flash, but using LED's
Is there something that can be programmed to release power for a set amount of time, from an input of a "ping" of voltage?
Full story i guess - i Have a Miops (sound/light trigger) for my flashes [which totally suck because they emit light for too long/ aren't very bright] via external 2.5mm to PC sync cable. I've also made a DIY 100W LED chip light, I want to have the Miops turn on the LED chip(s) On for 0.0004 or less.
Yes something already exists called the Vela One flash, But an $840 purchase isnt something i can do.
Arduino would work for firing the strobe I would think.
So you want LED so it can be low voltage / not electrocute yourself?
you can certainly do this with wiringpi if you're able to use google and copy and paste simple code. i can't be arsed to read up on the miops so i'll assume that it effectively bridges connections when triggered.
you'll want to connect the miops across the 3v rail and a gpio pin so that it can be read as input. you'll then want to connect a suitable relay across the 3 or 5v rail and gnd, using another gpio pin as the trigger.
i would assume that an arduino could be used too or even a 555 timer chip if you want to really simplify it.
>>971385
Dude, even normal "slow, not very bright" xenon flashes have their peak powers measured in tens or hundreds of kilowatts. Air gap flashes use even higher peak powers.
Sure, LEDs can produce more light per watt, but even then, a 100W LED running at 100W isn't going to do jack shit. You probably need to compromise on light output and still need lots of LEDs, overloaded brutally. Your electronics design problems will revolve around the LED drivers, their power supplies and the LEDs themselves, not around the timing generator.
If this was my project, I'd start by finding out how much light I actually need, how much I can overload big LEDs and what kind of LEDs could produce the required amount of light using reasonable number of LEDs. (And then, after seeing how big/expensive it would be, reconsider the requirements and/or the sanity of the project.)
Btw, you can produce under 400µs pulses with normal xenon tubes by a) reducing the total energy and/or b) by turning them forcibly off. Their afterglow might still cause problems, though.
Just out of curiosity: what kind of pictures you're going to take?
>>971550
I've done a lot already with my flashes here's an example.
>>971627
Also was planning on making multiple(around 6) 100W led lights and connecting them all together.
>>971385
LEDs are the wrong tool for the job. Xenon flash tubes will do a much better job at a fraction of the cost.
For a 400us pulse, one joule of energy corresponds to a power output of 2.5kW. Typical flash tubes can handle 20J+, corresponding to a power of 50kW. You aren't going to get anywhere near that with LEDs.
Flashes lasting <10us are easily attainable. With some effort 1us is attainable.
For a short flash, you want relatively low capacitance, high voltage (to compensate for the low capacitance), low parasitic resistance and inductance (to ensure a fast discharge).
>>972336
How stable are xenon flash tubes?(it seems handling the capsitors/other stuff needed to power them is dangerous if you're a pleb like me)
And an extreme example would be helpful!!! because all im really finding on the internet is small little 5v pre built stuff.
I have zero knowledge of electrical stuff, I know how to do instructions and solder.
i've found a xenon tube:RM8059F with this info
4800 J -energy (im guessing higher is brighter?)
Quartz 5500K -Material
250 -vmin (guessing Volts minimum)
500 -Vnom (guessing what works best?)
600 -vmax (guessing max before bad stuff happens)
Guessing i'd need a Capacitor:
ZS-1052/1
~12 KV -output voltage (no clue)
300 V -input voltage
0.047 uF -triggercapacity (no clue)
No clue how much power i'd need/ if theres an easy powersupply.
I used a laptop battery pack for the LED. Also i cant read electrical spec sheet things with the weird arrows and squiggly lines.
>>972403
The instructions with this is about all i can understand, but no clue how to power it, or how powerful of a tube i could use with it.
http://www.xenonflashtubes.com/optical-flash.html#instr
>>972403
> I have zero knowledge of electrical stuff, I know how to do instructions and solder.
Then the first step needs to be acquiring some basic knowledge of electronics. You aren't going to get very far without it.
> i've found a xenon tube:RM8059F with this info
> 4800 J -energy (im guessing higher is brighter?)
That's way too large for short flashes. Typical 20-30mm tubes are rated at 20-100J per pulse. 4800J/400us = 12MW. (4800J is ~3x the energy of an M-16 round).
> 600 -vmax (guessing max before bad stuff happens)
You can probably exceed that for short pulses. The limiting factor is the point at which the tube triggers without an applied trigger pulse (which are usually ~5kV).
> Guessing i'd need a Capacitor:
Yup. If you were to connect it to a steady 500V source then trigger it, it will conduct until it fails. So you trickle-charge a capacitor so that there's only a finite amount of energy available for each pulse.
> ZS-1052/1
This is the trigger transformer.
A typical flash tube has three pins: an electrode at the end of each tube and another one (for the trigger pulse) at the side. You charge a capacitor which is connected between the end electrodes. You then apply a pulse of a few hundred volts to the primary of the trigger transformer, which generates a pulse of a few thousand volts on the secondary, which is connected to the tube's trigger electrode. This ionises the gas, causing it to conduct. The energy stored in the capacitor discharges through the gas, producing a flash. Once the capacitor is empty, conduction stops, the gas de-ionises, and you start over.
This site provides a reasonable overview:
http://www.bristolwatch.com/ele/
> No clue how much power i'd need/ if theres an easy powersupply.
It's fairly simple to generate 340V DC from 120V AC mains, or 680V DC from 240V mains. Battery-powered flashes use some form of switching regulator to generate high-voltage DC from low-voltage DC.
>>972410
> The instructions with this is about all i can understand, but no clue how to power it, or how powerful of a tube i could use with it.
It's powered from 4-6V DC, so either 4x 1.5V cells or a 5V PSU, or USB. Most of the circuit is the 300V DC power supply. It's designed for a specific tube.
But the pulses will probably be much longer than 400us. You can get shorter pulses by using a lower-value capacitor. But ideally you'd want to take advantage of the fact that the pulses are shorter to increase the peak power, which means increasing the voltage. Which would mean changing most of the parts (and possibly even changing the PCB to increase clearances; 1000V can jump across an air gap of a mm or so).
The biggest problem is that it's hard to produce a design based solely upon theory because you can never get enough details on the tube. You basically have to make some educated guesses, create a circuit, observe its behaviour, and adjust.
>>972447
You should think about reducing the shutter time. The duration of the flash isn't the issue it's how quick the image is captured. You can go for a long flash/quick shutter or short flash/long shutter.
>>972514
Would have to be a hell of a fast shutter to beat the speed he is aiming for with the light. There are those mirror less cameras now though maybe they can do it.
