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Showing posts from January, 2014

PCB etching with vinegar... (part 3)

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Ok, quick post while at lunch. This is a recap of my progress...
1st attempt: Thermal transfer was pretty good, but did not let it etch long enough so that it's a big short everywhere.
2nd attempt: Thermal transfer was also pretty good, etching was good, but some traces shorted and some open. Might be usable.

3rd attempt:
On that attempt I changed the artwork to have a ground surface. I figured that it would speed up the etching. Also did some trace in-between the pads smaller so as to avoid short.
Unfortunately my paper moved while ironing... So useless to go through the etching part.

This is turning out to be a bit harder that I had anticipated, but I am making progress and learning from my errors.

Stay tuned.

PCB etching with vinegar... (part 2)

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Ok, so this is part 2 on etching a PCB with vinegar.

This time it's for real. I printed my design on a glossy grocery add I just received. I used the most glossy and cheapest paper quality I found.


Using a paper that feels cheap is apparently good because it will soak up the water and will become pulp more easily when time to be removed.
I cleaned up the copper board with one of those synthetic ScotchBrite type of washing sponge so that it was all shinny. You don't want finger grease on the copper. I also cut the copper board to the same size as my PCB artwork.


Next I heated my wife iron (don't tell her) at the 'wool' setting. Once ready the first thing to do is warm up the copper board. Leave the iron on it for about 30s. Then flip your printed artwork on the copper surface. This will somewhat glue the paper to the board so that it does not move when you start moving the iron on it.
I then put the iron on the paper and moved it a bit around trying to apply heat ev…

PCB etching with vinegar... (part 1)

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Ok, we all know that we can use FeCl or a mix of muriatic acid and hydrogen peroxide to etch PCB, but those are nasty chemicals that I don't really want to mess with. Reading on the net I found people using white vinegar, hydrogen peroxide and salt, all stuff you can buy at your local grocery store!

This will be a multi-part post where I will show my experimentations on this. Note that I have never etched my own PCB so you will get the full newbi experience.

My first test is just to see if this mixture can really remove some copper. So I just cut a small half inch square and give it a try.


The mixture according to what I read is 60% vinegar and 40% hydrogen peroxide and some salt... So I measured that and put that in an old plastic cup and dropped my small copper piece in.

Apparently this thing is supposed to be bubbling... So I added a bit of salt directly on the copper piece.

As you can see this had an effect and a reaction is occurring. I let it doing it's thing for 15 minu…

TP-LINK TL-WN725N on a RaspberryPi

Ok, got a TP-LINK TL-WN725N from MasterVox Electronique yesterday (http://www.master-vox.com/) for 15$ with the intend to use in on my RaspberryPi. The key was a v2 of the TL-WN725N.

Off course it did not work out of the box. After a bit Googling and failed attempt I finally stumbled on this post:

http://www.raspberrypi.org/phpBB3/viewtopic.php?p=462982#p462982

Which was the key to success. The trick is really to get the right module for your kernel.

Arduino and RaspberryPi low temperature tests

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For the past few months I have been working on a project that required a RaspberryPi and Arduino (and some other components) to survive Quebec temperature.

For those who don't know our temperature, winter can easilly reach bellow -30C (-22F) and summer we sometimes hit around 30C (86F). This past few days have been quite cold reaching in the -26C with a wind chill effect of -35C so it was the best time to perform a cold powered-on test.

The setup was simple. A RaspberryPi running Raspbian with a DS18B20 temperature sensor, a Startech 4 port USB hub where an Arduino Uno is attached. Every 15s a script would record the temperature and every minute an other script would look (using lsusb) to see if the USB hub and Arduino were still alive. The setup looked like this:


The plastic container was scealed with tape, put in a 'ziplock' bag and left overnight on the rooftop of my car.


The power was provided by a small 75W APC DC-AC power inverter sitting in the car and connected to …