Microflash development 2

[Rhys]

I have a question. If you wanted to do high-speed imaging with exposures of 1/1,000,000th of a second while realising that the absolute cheapest microflash commercially available is $3,000 with the most expensive being $100,000+, would you build it yourself or not?

If you wanted to build it yourself, would you prefer to build it out of mail-order parts, ebay parts, parts from the local car spares shop or parts from a specialist online retailer such as Amazing1?

I realise not everybody has a scrapyard or electronics shop in their town. Even scrapyard parts are possible.

[Mark_48]

Is this from the viewpoint of doing high speed photography as strictly a hobby or as a possible commercial venture producing income?

For intentions of a hobby, I'd likely attempt to build it myself and source parts from any place that I could scrounge stuff up.

If I had aspirations of doing paid commercial work, initially I'd look into renting the necessary equipment as needed to fulfill a project. If you're going to do it right you need equipment that will produce consistant results, reliable, and safe to use at a clients location.

[Rhys]

It will be safe with repeatable results or I will not be very happy. High-speed photography is an occupation that takes a lot of time. My intention is to produce a plan for an open-source microflash that anybody can build. To that end I asked the question.

At the moment I'm looking at using a relay rather than a 555 pulse unit to produce the pulsed current for the transformer. I'm still thinking of using ignition coils. I also had a sudden thought that it's not going to be beyond anybody to use a pair of 20KV coils and then to wind their own mini-transformer with 100 turns on the primary and 225 on the secondary to raise the 20KV to 45KV for the ionisation phase.

If I can produce a plan that anybody can follow then I'll be happy. My aim is also to produce a plan that can be followed anywhere in the world from somebody in a garden shed in Britain, somebody in a shack in Africa to somebody in a workshop in Canada. I'm also trying to make the components as universal as possible.

[Mark_48]

Buy a kit. If you look at the time you've spent trying to hunt down parts and collecting junk that may not be usable, for about $100 you'll get something that will likely work and if it doesn't, you've got the kit maker to fall back to. All you'll need after this is the HV diodes and your in business. The kit below has a downloadable PDF construction guide and schematic. A couple of videos show construction and a working arc.

Here's just one found in a Google search....
http://www.imagesco.com/science/high...e_devices.html

Winding transformers is an art and you'd need to have knowledge of the physics of magnetics - core permeability and saturation, gapped or not gapped, iron, ferrite, or air core. Need to get air out of HV transformers too, which usually is done by vacuum impregnation of a silicone varnish of sorts. Waste of time and money unless you know what you're doing.

[Rhys]

There's more to it than that. I already have the gubbins to make the pulse generator. I can do that with either a relay set to constant vibration or a 555-based pulse generator. As far as the coil, I don't know the specs of that particular ignition coil. I do know that I have two coils in mind. One is an Accel coil that gives 60KV and the other is a fairly boring Bosch coil that gives 30KV.

Edit:
I'd already started the pulse generator. Most of the components are on the PCB. I took a break when somebody came up with "it won't work" as I needed to investigate. Having done that and found it actually will work and that people do use that circuit though with an additional diode I shall continue to work on the circuit to complete it. My main problem is I need excellent light to work in and for it to be cool enough in the garage to work and for a nice quiet house. I had a big splodge of solder joining two tracks. I used the daylight today and my tool to clean that away. I've got to work on planting the trees tomorrow, having borrowed a rotavator to break up the top few inches of roots and soil. I imagine that sometime next week I will have a few minutes and daylight to do more soldering etc.