Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Heck, I use photo resist board for real PCBs, it doesn't work out that expensive, it's probably cheaper than Press-n-Peel.
It's easy to build a UV exposure, the cheapest way is to lay your board with the artwork on top on a table held down with a peice of glass. Use compact black light for the UV source, the easiest way is to put it in an old desk lamp and direct the beam at your PCB.
Having tried many methods over the years, including printing onto magazine pages,photo-resist etc. and I would say Press-n-Peel is one on the best I have found. It is quick, easy and fast and I have had spectacular results for my SMD work and double sided boards, with achievable edge definition and fine track widths far better than using paper. I use laser labels to stick correctly sized pieces of P-n-P to normal A4 sheets and have not had a 'jam' on my laser printer yet. As for cost, a 20 sheet pack shipped to Sheffield UK from Techniks in the USA is US$64.50 or about £33.00 which compared to Maplin where you get 5 sheets for £15.52 which is almost twice the price at £3.10 per sheet ! and you have to collect.
I am pretty sure it is the one we are talking about. The stuff I use said on the bottle: "First Aid Antiseptic Oral Debriding Agent".
Active ingredient: Active ingredient: Hydrogen peroxide (stabilized) 3%
Peroxide is the 'common' name, it is a a bleach for hair and an antiseptic. It comes in different strengths, and loses strength whilst stored. The 'strength' can be measured by the volume of oxygen which is liberated from a given volume of Peroxide on an organic matter sample.
I think the USB and processor can run from the same clock source.
But but you can decouple them to go into a low power mode where the processor slows down but the USB is still active.
A quick look at the datasheet.
Asynchronous dual clock operation, allowing the
USB module to run from a high-frequency
oscillator while the rest of the microcontroller is
clocked from an internal low-power oscillator.
A good way to remember this is use the alphabet...A to W not W to A...
The explanation is simple..if you have a high concetration Acid (let's say sulphuric acid 10 mole) which would eat through any type of metal, if you would slowly dump the acid into water, the reaction can be controlled by the pouring of the acid into the water.
Let's say you dump the water into acid, then you would have a little bit of water reacting with a large amount of acid as the pouring process starts.
This is very dangerous because of the large amount of concentration of acid is going to react with every molecule of the water, giving off much heat.
I am no scientist but this was 8th grade bio-chem, which is basic reaction control.
Use this rule for adding acid into pretty much anything, espcially water.
I could never get the H2O2 + HCL mix working, but Copper Oxide + HCL has worked Like a Charm For me. I just use a air bubbler from ebay to help it go a bit quicker and its worked pretty well over the years. Ive been using the same etching solution for quite some time now.
The only problem is that my HCL is from the dollar store (toilet cleaner, 10% HCL) and bubbles, so I have to do it in the shower. Still, for $1 I cant beat it (but the copper oxide is a different story-I have to make it from copper carbonate-which I got through a pottery store)
I've heard (or read) from some people that standing up the board vertically in an etch tank versus laying it down flat makes it go quicker? Just a myth or reality? I could understand that when the board is vertical, maybe the dissolved copper would 'sink' to the bottom keeping the etchant more pure around the PCB. I suppose a bubbler would just fix this problem though?
And also, I just have a question about waste disposal of muriatic acid and H2O2. I'm pretty sure that if it's toxic to breathe, it definately is not safe for a septic tank. Any suggestions? I do have access to my Chemistry lab at my University, so maybe I could bring the stuff there, since they usually have a ton of inorganic waste. Don't know how happy they would be though lol!