This is my home made PCB UV-LED exposure box housed in an old scanner. The countdown timer is custom made using ATtiny2313 uController. The display unit is a 4 digit 7 segment display module. The firmware was written in CodeVisionAVR C compiller and the LEDs used for this project are 5mm high brightness (2000 mcds) UV LEDs. I used rice paper to diffuse the LEDs. The total cost is around 15 euro. Please don’t ask for schematics, pcb and firmware.