Recently on our Hack A Day forums a member asked about getting some VGA testers made in our “Request and Commissions” forum for a charity called the World Computer Exchange, who take old office PC’s and freshens them up to be used by children in developing countries for their education.
I sort of wanted to do a no brainier electronics build as I had been working on that Apple II weather display for quite a while at that point. I say no brainier because I decided to use one of the many already designed vga testers out there and all I really had to do was get it to fit in whatever box we ended up with.
I choose the deogen because it was already featured on Hack A Day, supports multiple raster patterns and resolutions (640×480 through 1280×1024), is already pretty darn small, and uses an ATTiny 2313 which is good because I am already set up for AVR micro controllers. For a case I choose to use some plastic “Ice Breakers” mint boxes, which due to their oval shape makes it quite a bit smaller than an altoids tin. The challenge is on to shove a PCB, switch, 9V battery, 2 buttons and a vga connector in the cramped space.
Join us after the break for a pile of pictures and some build notes.
[James] has been refining a method of negatively etching metal with a laser. He had been using a product called Thermark which is designed for this process, but it’s quite expensive. He found that paint designed for wood stoves works just as well. To prepare the surface he bead blasted it and then cleaned of the residue and finger prints off with acetone. The board was preheated in an oven before covering it with the spray paint. He ran the laser at 98/100 power and 90/400 speed at a step size of 0.1mm to achieve the results above. This should immediately make you think about making circuit boards. We’d love to ditch the toner transfer and we’re always looking for one more reason to get a laser cutter.
[James] is interested in reverse engineering some integrated circuits. One of the biggest hurdles in this process has always been just getting to the guts of the chip. He used acetone to dissolve the plastic case but had trouble getting through the epoxy blob. Commonly, the epoxy is soaked in nitric acid for a few minutes but [James] didn’t have access to that chemical. Instead he popped into the local music store and picked up some rosin (used to make violin bows sticky enough to grab the strings of the instrument). After boiling down the rock-hard rosin and the chip for 20 minutes, he got a clean and relatively undamaged semiconductor that he can easily peer into.
[Zach Charat] didn’t want to carry around yet another card with him so he transplanted the RFID guts from his card to his phone. Soaking the card in nail polish remover for twelve hours got him nowhere, but when he broke out the acetone the card was falling apart in 30 seconds. Above you can see the tiny chip and loop antenna that were left after ditching the plastic. The black bits are electrical tape which he then used to embed this in his Palm Pre’s touchstone charger plate ( which we just saw this in a hack last week).
We’ve covered homebrew PCBfabricationtechniques about a billiontimesbefore. What sets this tutorial apart is that it collects many bits of knowledge otherwise scattered all about the web, and then depicts the entire process on video, from initial printing to cut PCB…because reading about it versus seeing it done are two different things entirely. They give a number of immensely useful tips throughout: choice of materials and where to get them, tools and techniques, and dispelling several myths about these methods (for example, they’re adamant about notusing acetone to clean toner from the PCB). Well worth the 30 minutes to watch. If that’s too much and you’ve been stuck on just one part of the process, the tutorial is in three segments.
Trimming finished boards on a paper cutter? Who would’ve guessed?
While we hope you enjoyed our How-To: Etch a printed circuit board, toner transfer certainly isn’t the only way to get the job done. [Garrett] from macetech has recently been playing around with using an Epilog laser to etch PCBs. He started by applying a thin even coat of flat black spray paint to the copper board. The laser is used to remove paint in areas that you want the copper removed. Once that’s done, you proceed with etching as usual. He eventually removed the paint mask using acetone. The result has very fine, sharp traces, but most people that have tried this agree that using spray paint is less than ideal.
Making a PCB is very simple; it does not consume a lot of time and the results look professional. After reading this How-To and watching the step by step video, you will be able to make your own PCB in your workshop using just a few inexpensive materials.
Many people use protoboard and point-to-point wire everything, but needing multiple copies of the same circuit is the reason that forces many away from using protoboard. After making your first circuit board, you might not point-to-point wire anything again!