Simple way to turn a Xenon flash gun into a strobe light? - Page 1
Forum section: electronics / general

author: eti
author_rank: Super Contributor
timestamp: January 25, 2023, 10:54:02 pm
content: Simple way to turn a Xenon flash gun into a strobe light? As per title - I have an old "Miranda" brand flash gun, and wish to convert it to an adjustable strobe. Is this beyond trivial? Also, yes, am aware of high voltages and currents etc.Thanks!

author: themadhippy
author_rank: Super Contributor
timestamp: January 25, 2023, 11:09:13 pm
content: QuoteAnd the risk of triggering photosensitive epilepsy?Easiest way would be to work out what connection on the hot shoe fires the flash and have something trigger that,however you'll more than likely get a lousy duty cycle.Better to strip it down and build something from scratch just reusing the trigger transformer and tube

author: eti
author_rank: Super Contributor
timestamp: January 25, 2023, 11:10:39 pm
content: Quote from: themadhippy on January 25, 2023, 11:09:13 pmThe question was of a technical nature, not one asking where I "ought to" or not. Appreciate the help thanks for helping

author: Ian.M
author_rank: Super Contributor
timestamp: January 25, 2023, 11:14:29 pm
content: Probably remove the flash capacitor and re-fit one an order of magnitude lower value to improve the recharge rate and reduce the energy per flash enough not to kill the tube due to heat build-up from repeated firing.

author: langwadt
author_rank: Super Contributor
timestamp: January 25, 2023, 11:18:03 pm
content: it is probably slow recharging and you probably have to reduce the high voltage capacitor substantially to not burn the tube out

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2023, 02:54:47 am
content: not possible and dangerous.Disco strobes are cheap and readily avail,Most Xenon are replaced by bright LED.j

author: themadhippy
author_rank: Super Contributor
timestamp: January 26, 2023, 03:24:15 am
content: QuoteWhys it not possible,have you seen a camera fitted with a motor drive and a decent quality studio flash?Quotewhich,unless you spend serious amounts of cash lack the feel of a proper xenon strobe.

author: eti
author_rank: Super Contributor
timestamp: January 26, 2023, 04:09:25 am
content: LED strobes are garbage. Anyone worth their salt knows they’re NOTHING LIKE xenon. The world has become overly enamoured with LEDs being a replacement for literally every lighting category; this is called “the honeymoon period”

author: Gyro
author_rank: Super Contributor
timestamp: January 26, 2023, 10:25:45 am
content: Camera / flash gun tubes aretinycompared to proper strobe tubes. They are intended for very low duty cycle operation and have very low total discharge life - how many thousand photos is anyone going to take over the life of a consumer flash gun? Professional studio ones are different, they have big tubes.You would need to drop the discharge capacitor to a tiny fraction of what is typical 330uF used. Maybe 1uF - 10uF depending on frequency. This would drop the energy dissipated in the tube, but also the duration of the flash discharge itself, making it harder to see.The flash trigger from the camera is usually just a switch contact, but in a lot of cases, this directly connects to the small capacitor that gets discharged into the trigger transformer, so you would need to check out the actual circuitry to trigger it electronically, or just use a 555 timer and a relay.You haven't given any useful information on what you intend to use the 'strobe' for. Emergency beacon? freezing motion? Disco ()? Flash frequency / range? The longer light pulse possible with LED strobes (compared to the tiny discharge duration of a flash tube with small capacitor) makes them far better for pinpointing locations.P.S. Here's an ignition timing strobe that I built donkeys years ago, triggered by the the spark plug HT lead. No it's not mains isolated, but none of them were. Note the difference in strobe tube size against the camera flash tube alongside. I used a 1.8uF film cap btw....

author: Wolfram
author_rank: Frequent Contributor
timestamp: January 26, 2023, 10:39:49 am
content: Along with reducing the capacitance as discussed (I would go for something in the 3.3 - 10 uF range), you need to find a way to trigger the strobe at a fixed rate. The trigger interface of camera flashes is a signal that needs to be grounded, available on the hot-shoe connector and often also on a secondary coaxial connector. The voltage level on this signal can be anything from a couple of volts up to around 300, see here for examples:https://www.botzilla.com/page/strobeVolts.html. I would go with any simple oscillator, using a 300+ V open collector NPN transistor to generate the trigger signal.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 26, 2023, 01:58:25 pm
content: Easy way is to add a SIDAC to automatically trigger the strobe when charged.http://donklipstein.com/kmaxhack.html

author: Brumby
author_rank: Unknown
timestamp: January 26, 2023, 02:09:25 pm
content: Quote from: jonpaul on January 26, 2023, 02:54:47 amSorry, but it is quite possible.Doesn't mean it is a good idea, though.This:Quote from: Gyro on January 26, 2023, 10:25:45 am

author: BrianHG
author_rank: Super Contributor
timestamp: January 26, 2023, 02:13:18 pm
content: Quote from: eti on January 26, 2023, 04:09:25 amThat is a design choice. It would take real engineering and big$ super-high CRI leds to get anywhere near a xenon strobe, yet be safer for the eyes missing all that UV and near and far IR. But who would want to spend 1k$ just on the right custom laser-led with approvals and circuitry VS a 50cent xenon tube.Maybe one day a serious effort will be made with a custom LED die, but it wont be anywhere cheap as a 50cent xenon tube.

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2023, 02:54:14 pm
content: Strobe was developed in WII by Harrold Edgerton at MIT, the "Father" of electronic flash.See his papers and books and sir te of EGG that manufacturs the fast strobes, flash, tubes for very high speed use.Power in W = joules/sec.Each flash energy in Joules is 1/2 C *Vexp 2.(volts/farads)Thus the average power consumed in W = # flashes /sec * joules /flash.A portable photoflash recharges the cap in perhaps 20..120 sec.A disco strobe is usually 10..30 Hz.Thus disco strobes power can be 10s..100s watts,Photoflash average power perhaps a few watts.A strobe power supply needs 10..100X the power and power source of a photo flash.No you cant do itJ

author: Gyro
author_rank: Super Contributor
timestamp: January 26, 2023, 05:52:43 pm
content: As I mentioned, we have no information on what kind of strobe the OP wants to cobble together. From his history though, I seriously doubt that it is a disco light.The timing light that I pictured earlier used 1.8uF and 320-340V rectified peak. It was bright enough to see the timing marks in the confines of an engine compartment and worked up to around 1500 rpm / 25Hz irrc and, with the strobe tube used, would have a decent operating life. It would bepossiblefor the OP to bodge something low frequency, even if the tube only survives for a few minutes.Whether it isfeasibledepends on some clear input from the OP.

author: edavid
author_rank: Super Contributor
timestamp: January 26, 2023, 05:56:17 pm
content: I think a lot of the posters in this thread missed an important development that happened about 50 years ago.That was when photo flashes were introduced with a variable power feature controlled by a photo sensor. They were and are called "thyristor flashes", even though it's now common to use power FETs for switching. The xenon tube is turned off when the sensor detects that enough light has been reflected from the subject.At the lowest power levels, recycle time decreases dramatically, usually to 50-100ms.So this type of photo flash could easily be modified into say a 10Hz strobe, without having to bother changing the photoflash capacitor. If the flash doesn't have a manual power control, you can tape on a piece of paper to reflect the light into the sensor and trigger the early termination.Of course OP didn't bother to tell us what kind of flash he has, but we can't expect him to start including actual information in his posts, can we

author: Buriedcode
author_rank: Super Contributor
timestamp: January 30, 2023, 04:06:21 am
content: To the OP:what is your application?You have a history of posting XY problems, and whilst you seem (violently) opposed to LEDs - if you're using a strobe for tach, then I don't see why a gas tube with all its hassle would be any better. Of course there are other applications where it would be more fitting, but you haven't provided any clue as to what that is.As has already been pointed out, the tubes for camera flashes are for low duty, high power. And even then they do still get hot. Try it yourself with the suggestions already provided here and see how long the tube lasts..

author: james_s
author_rank: Super Contributor
timestamp: January 30, 2023, 04:44:53 am
content: It's not only possible, it's quite easy. Replace the capacitor with one of much smaller value to reduce the energy per flash and increase the flash rate. I used to build strobe lights out of disposable camera flash circuits which could often be had for free from film developer shops. A diac or neon glow lamp can be used as the trigger. It's almost as easy to build from scratch though, a xenon strobe circuit is very simple.

author: Gyro
author_rank: Super Contributor
timestamp: January 30, 2023, 10:08:18 am
content: Quote from: Buriedcode on January 30, 2023, 04:06:21 amI wouldn't waste your time. The OP lost interest after less than a day and went to play in the 'EV-based road transportation is not viable' thread, just a few threads away. He hasn't bothered to respond to any questions.