Building a UV exposure box

There are two methods of using etchant resist when making circuit boards. We use the toner transfer method that requires ironing on laser toner to the copper, but you can also use chemical resist that reacts to ultraviolet light. [Bogdan] decided to start doing more of the latter so he built a UV exposure box to make the process easier.

It is possible to use flourescent light bulbs for this, but he decided to use UV LEDs, a method we’ve also seen before. But there’s always room to innovate, and [Bogdan] built-in a couple of nice features that are new to us. Because the UV light can be bad for your eyes, he included a set of red visible-light LEDs on the bottom half of the box that are used to align two layers of exposure mask when making double-sided boards. There’s also a switch that automatically shuts off the UV light when the box is opened. And as the coup-de-grace, he added a programmable timer to regulate the exposure, using his newly created box when etching the PCB for it.

Mr. Burns prevents sun burns

[nmcclana] wrote out this very detailed instructible on building Mr. Burns, a sun burn alarm. ¬†Enter your skin type, sunscreen type, and UV levels for the day and Mr. Burns will let you know when it is time to go seek shelter or re-apply that sunscreen. Built on a Propeller platform, he’s using a blue LED as the UV sensor. He mentions that the device is fairly accurate, however people tend to put sunscreen on too thin and that will throw off the readings. There is a video of it in action on the instructible.

Coachella lamp

This little art piece might be just the thing to add that mad scientist look to your room. It’s called the Coachella lamp and it makes use of several throwback display devices. At the top an Argon discharge lamp puts out ultraviolet light. Protruding from each of the four sides you can see a set of decatrons. There’s also four Nixie tube bar graphs standing tall from each corner of the base. The final touch is the colored glow in the center which is provided by LEDs. We’ve embedded some video of the device after the break.

The lamp is powered by a wall outlet and controlled with an Arduino. We’ve seen deactrons used as timing devices and would love to see some clock functionality added to the lamp. Trying to decipher the time from the different Nixie displays would put this up there with some of those other hard to read timepieces.

[Read more...]

Monitor UV exposure with your sunglasses

Tired of those awful sunburns? [Nikko Knappe's] UV sensing glasses will warn you before you become crisp and red as a lobster. The bump added to the bridge support hides a TSL230R light frequency sensor. The device automatically switches on when the arms are unfolded and starts tracking cumulative exposure. If it detects a rising UV level, or you are about to burn based on skin type, an LED inside one arm of the frames will flash to inform you.

This has some potential if you think David Brin’s Earth outlines how climate change is really going to play out. Either way it’s still fun and we give bonus points to [Nikko] for disguising the lilypad that controls this as a flowery hair-pin.

Don’t put that EPROM in your mouth!

[Jeremy] had some chips on hand that included EPROM.¬† We’re not talking about EEPROM, we mean EPROM that need a UV light source to erase. Most people don’t want to drop a few hundred dollars on a dedicated EPROM eraser, there must be another way.

Boy, EPROM really suck. But so do pacifiers and he already had a solution for exposing those to UV. He pulled out his $30 UV pacifier cleaner and tossed the chip inside. Two times through the cleaning cycle and the data was gone. We’ve looked into using UV LEDs to do the job but some experimentation shows that it doesn’t work. These pacifier cleaners are cheap and easy to get a hold of. The real question is are you still using chips that require UV for erasing?

PCB light box in a scanner shell

scanner-exposure-box

[Kizo] repurposed a flatbed scanner to use as an exposure box for making printed circuit boards. Exposure time is controlled by an AVR ATtiny2313 microcontroller. The device is connected to a separate display board to control four 7-segment displays using one shift register for each. Time is set in ten second increments and once started, switches on the lights with a relay. Once the right exposure time has been reached, the lights are switched off and a piezo speaker is buzzed. There’s no mention of they type of bulbs he’s using but they look like compact fluorescent with tin foil beneath as a reflector.

If these are just CFL bulbs, how will the performance compare to a light box based around a UV light source?

[Thanks Jake]

Ghost matrix, glow printing

Ok, there aren’t any usefull applications we can think of for this one, but we want one really badly. This is a combination of a miniPOV, some UV LEDs, a CNC rig, and some glow in the dark paper. The Ghost matrix works similar to a dot matrix printer where it flashes the UV light to activate the paper. The final effect is very nice. Great job on this one.

[via Laughing Squid]