DIY Keychain TV-B-Gone

by **oPossum** » Tue Feb 26, 2008 11:17 pm

Here is a single sided SMD design for use in a keychain enclosure.

Disclaimer: Has not been fitted, built or tested.

Schematic, board and parts list

.

by **jasonx** » Wed Feb 27, 2008 7:31 am

wow looks good oPossom I might try this as it is single sided
I did not see the parts list though

by **magician13134** » Wed Feb 27, 2008 10:21 am

Oh wow! I'd been trying to design this on my own, but was coming up short, thanks for doing this for me! As soon as I can get the components, I'll put it in my case to see if it fits. And one more question, doesn't the coin cell need to touch copper? Or not..?

I can make up a circuit board later just to verify that if fits, but this looks fantastic!

by **oPossum** » Wed Feb 27, 2008 10:45 am

Sorry about the parts list - it's fixed now.

A negative battery contact (keystone 2990) is used so no copper is need on the back side of the board.

Let us know how it all fits. I expect some tweaks will be necessary.

by **magician13134** » Wed Feb 27, 2008 2:43 pm

This is fantastic, oPossum!!! Once again, great work!

by **Probedude** » Thu Feb 28, 2008 9:10 pm

Nice work once again!

by **jasonx** » Mon Mar 03, 2008 11:19 am

A home etch test

Close up

by **nutt318** » Mon Mar 03, 2008 1:07 pm

wow, those look great. How are you doing yours? Like what kind of material are you printing on?

by **darus67** » Mon Mar 03, 2008 1:09 pm

Shiny!
Did you use toner transfer? What etchant?

by **jasonx** » Mon Mar 03, 2008 2:37 pm

First of all I know the surface mount board has no copper pour
I was just testing
Right I used a horrible cheep 1.6mm copper clad board
press and peel blue http://www.techniks.com/how_to.htm
cannon lbp2900i laser printer
gbc laminator http://www.pulsarprofx.com/PCB/a_Pages/ ... urces.html
#00 steel wool http://www.cleanyourcar.co.uk/accessori ... d_377.html
pure acetone not nail varnish remover
ferric chloride

I was trying to use magazine paper but I was getting inconsistent results
I used a laminator for the same reason,I am a man therefore I can not use a clothes iron :lol:

I ran the board through the laminator 4 or 5 times.
I was using automotive scotch brite pads from the body shop at work but they make an awful mess.so I tried the #00 wire wool I had in my garage.
And all the nail varnish removers I brought localy were banned they had lanolin,wheat protein and all manner of lady nail friendly chemicals in.

To etch the board I used warm ferric chloride in a shallow plastic dish.
I cut a 3" square piece of micro fibre cloth and folded it into a small rectangle which I then folded ever the end of an old pen and secured with a zip tie.
I cleaned the board with the #00 steel wool and then wiped down with acetone.
I held the board (with glove) over the dish while I dipped the micro fibre in the ferric chloride and then gently brushed the board once or twice and then re dipping and repeating until I had remover the copper from the areas I wanted.
I then removed the toner with the #00 steel wool under a running tap.
Idea came from here http://www.pulsarprofx.com/PCB/a_Pages/ ... chor-49575

In the picture next to my initials jw you can see a small pit this was caused by a piece of dust between the press and peel and the board.
I had covered this with etch resistant pen but that did not survive the etching method I described above.

by **magician13134** » Mon Mar 03, 2008 10:48 pm

I got my samples of the battery through-hole attachment today, but this week is so busy, I probably won't be able to etch mine until the weekend, but I can't wait!

by **jasonx** » Tue Mar 04, 2008 3:34 pm

I had this brilliant idea last night while trying to sleep so I mocked it up today to see if it would work.
I have had trouble drilling pcb's accurately and I thought could I put a camera under the drill press ?

please note this is just a bodge at the moment.
the pcb is placed face down and illuminated from above with the dremel led accessory on the right
on the left you can just see a piece of ohp transparency film taped to my laptop screen this has a circle drawn on it after drilling a test hole

usb web cam wedged in place

0.8 mm hss drill bit and hole in the bed illuminated by the led light

here is a video of what I saw on my laptop the picture was better before I compressed it
the first hole is a test I then drew the hole on the transparency stuck to my screen
the second two holes are drilled using the hole marked on my screen
this may be the most boring video on the net :lol:

http://s27.photobucket.com/albums/c176/ ... lltest.flv

I'm more than happy with the result and will have a go at building it properly at the weekend.

by **shadow** » Wed Mar 05, 2008 12:04 am

wow!

thats really smart! looked pretty effective too. nice one

by **Probedude** » Wed Mar 05, 2008 1:15 am

FWIW when I do my PCB's at home (photo method) I make all my holes 0.018" in diameter - no matter what the end size is really supposed to be.

This leaves a small clear 'hole' in the copper pad that serves as a guide to starting the drill bit. You just need to get close and the bit 'drop' into alignment.

Give it a try on a few of your pads and see if it helps you too.

Dave

by **oPossum** » Mon Mar 10, 2008 8:44 am

jasonx wrote:First of all I know the surface mount board has no copper pour. I was just testing

It is also mirrored. Not sure if you noticed that.

Your boards are AMAZING! Thanks for sharing your technique and results.

DIY Keychain TV-B-Gone

DIY Keychain TV-B-Gone

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