Let's cover some background information first. Strobes are one of those things mentioned all the time on forums such as planet christmas and used quite a lot in the US, when you read up on them they are either bought C9 type strobes or have been made by DIY people out of disposable camera flash units. The flash units are recovered from disposable cameras that seem to be relatively easy to get hold of in the US. Now in Australia this is quite a different story, disposable camera's were never that common and with the explosion in cheap digital cameras even less so. Super bright white LED's gave someone the idea to hook them up and turn them on and off under software control, using a 25mS on period in Vixen gives a good imitation of a flash unit. One circuit published last year at DIYC used a lm317 to provide a constant current driver for the LED so that voltage used was not critical, one issue with this is the amount of heat generated when used at 12v and sort of requiring that a headsink be used. [add link to diyc thread] The TPR1 came about purely from a desire from a member to have a premade PCB that fitted with the C7 covers that were cooped by FH45. Out of that simple request developed what is now the TPR1.