Probably everyone electronics hobbyist is dreaming about fast PCB prototyping method. Some of you are just ordering professional made PCBs, that is not always worth of cost, other are using easier way – Laser printer toner transfer technique which is not very accurate, third option is more advanced – ultraviolet light exposure of photo-resist coated PCB through film mask. This gives pretty good quality at reasonable price and doesn’t take much time.
The main thing that is necessary and expensive – the ultraviolet light source that is needed to expose sensitive layer of PCB coating. Yo can buy light source or as a hobbyist you can build one. Scienceprog has published a nice project on how to build a Ultraviolet light source. It uses 8x20W light tubes that gives a total 80W for one side. So the exposure time is just three and half minutes. Device can be used for double sided PCB exposure. And can produce a large number PCBs at once. Probably many of you may not need such big device, but some design ideas may be useful. As embedded part of this project is a count down timer with LCD built on AT90S2313 AVR microcontroller which can be replaced with newer ATtiny2313. It is simple timer which allows setting minutes and seconds. It controls a relay that switches lamps ON and OFF after timer counts to zero. Project files can be download here.