If I had to expose a double sided PCB with my previous exposure box, I needed to turn it on twice. (1 time for the top, and 1 time for the bottom) To solve this problem it was time to build a new version. This new version will do the 2 side’s at once.
This time I chose for LED’s instead of fluorescent light, so I designed some PCB’s to mount the leds on to. The PCB’s will be connected per 6. This allows me to exposure PCB’s off 20 * 30cm max. The top of the board has no solder mask. This works as a reflector.
Then came the biggest work: The case make. To save space I didn’t use the traditional flap open model but a kind of sliding model. Where the glass panels slide out.
You can pull the upper plate up to insert the pcb between the glass sheets and to clamp it.
The base plate with spacers and two side plates::
With the slider mounted:
Test with glass in it:
I added some springs on the screws to make the hinges clamp the glass
On the front I added some bulletsnaplocks.
The top plate mounted with the buttons / LCD on the place where they should be mounted.
For the power supply I used a 20V toroidal transformers. The voltage is a bit high, so I used some switching voltage regulators to power the led pcb’s.
(One of the voltage regulators is still on order.)
I made a new timer to switch the light panels. This new timer remembers the last exposure time, so you don’t have to remember it yourself anymore..
Build in the case: