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Touch Board Key Construnction

We all remember this thing - the touch control board. Also remember how ugly it is. Why? because the keys are ugly and there's no hiding the subunit anywhere... not a problem anymore. I've got to do something while I wait on a response from Ben @ mountainmods.


Raw 1" plexi cylinder arrives @ my house from the land of ..well... everything. McMaster-Carr, what DON'T they sell?


Setting the fence on my bandsaw to 3/4" for each 'key' section of the cylinder. This appears to be (by imperical investigation) the approximate best length for LED light spread of the blue and white LEDs I'm using. Any shorter and the light is too intense, any longer and the light is concenrated in the middle (bad as you'll see later)


4 keys cut. Note that these went for a little ride on the belt sander after these shots



My ingenious way of marking the center of a circle... I got lucky that the label on the solder was symeteric and had a line down the center of it. so I put a piece of tape on the key to be marked, marked one line, rotated, marked another. Boom, where the lines cross is the center.




Key secured in my drillpress, ready for the hole through it. The hole is to accomodate the wire going up to the touch-sensor's electrode (a sanded flat penny).


Drilled with a 5/32" straight through.


Preparing for the shallow 3/4" hole to accomodate the touch electrode (penny, which is about 3/4" diameter) with 3/4" wood spade bit (works fine on plexi if you go slow - plus is easy to center with the pilot drill!)

 

3/4" at 1mm deep relief drilled. (Ignore the holes in the bottom for now, I'll explain those shortly)


Touch sensor electrode in place (pre-sanding)



Sanded penny - touch sensor electrode. I plan on painting it flat black to match the rest of the parts - polished nickle or even sanded nickle won't look right. I'll get to that sunday when its supposed to be like 45*F out! yay!


Sanded Electrode in place. Still have to get gas for my torch to heat up the penny enough to solder some 24AWG copper stranded wire to it, and then paint the electrode. The wife is using my torch gas for the BBQ! Arg!


Marking centers for holes to accomodate 2 5mm LEDs (1 white, 1 blue)


Drill with a 7/64" (hey, I don't own metric bits!) bit and have just a little wiggle room (enough for the adhesive goop to sit in)


Holes drilled (yes, that's what those holes were for)


Chucking the key into my hand drill (the corded one) via a nail through the center to 'frost' the edges (evenly distribute light around the body of the key)


Sanding with 220 grit emery paper (flexes a lot easier than regular aluminum-oxide sandpaper since its on a fabric-like base)


"Frosted" key with electrode in place.


2x5mm LEDs, 1 white, 1 blue.


Key on LEDs (no illumination)... hrmm...


Key on LEDs (White illumination- a little too intense in one spot)


Key on LEDs (blue illumination (which in real life doesn't have that nasty aqua spot, not sure how to photoshop that out)... same problem.)


Time passes... I come in 3rd at a LAN tourney... I return home

Manufacture 3 more keys! Wrap them in aluminum tape to rid myself of 1.) Light leaking 2.) uneven intensity around the key ring.


4 keys with electrodes (1 flipped, just to show what the keys are, its sanded on the other side)


4 white LEDs with their tops sanded off. This also helps diffuse the light out of these narrow-angle LEDs a bit more, plus the fit into the holes I drilled perfectly now, I guess I drilled them just a little too shallow.


1 white and 1 blue 5mm LED GOOPed into place on each key.


Money Shots!

Lights on, white LED on (normal key state). A little intense in the one corner, but a lot of its the camera, and the angle.


Lights off, white LED on (normal key state). A small degree of light leaking out the bottom, but nothing that won't be cured when I spray paint the electrodes black, and spray paint the key bottoms black to eliminate light leakage)


Lights off, blue LED on (key touch state). It's a little less aqua and a little more blue in real life, but I was unable to get the effect I wanted in photoshop.


So that's the state of affairs. I've redesigned the front panel baste plate to allow me to have these keys perfectly aligned by CADing in 1.05" (the extra 50 mils for the foil tape) holes into the base plate design. I'm waiting to hear back from Ben at mountain mods about the ETA to get the new parts in my hands. Until then, I'll keep chomping away at what I can do.

For the time being, I'm going to split the chassis control board off from the board that has all the case indicators. For one, it was getting too big for me to use my favorite board fab house, and 2, I've dediced it'll get its own PIC for controlling 8 RGB indicators for ANY friggin color I like.

Until next time (and I'm not sure when that will be...) Stay tuned, same bat forum, same bat post.

 

Oh my god, that looks amazing! I want those buttons

 

Maybe I should clarify... these aren't mechanical buttons and will not be directly exposed. They will be hidden behind the top plate of the 1/8" smoked gray plexi you saw in the previous post.

 

Just two questions:
What was the stuff about the guy breaking into your house?
How are you getting a 16f872 on USB, or are you just stealing power from the USB?

This is a really great case: keep up the good work


ch424

 

Iwe seen this pic somewhere on the internet before

By the way, nice case you got there

 

Q1: It's a bit of an inside joke, that's actually Pug. Nobody broke in, but you may remember a post of his about Hexadragon a long time ago called "The Return of the Spy" or something like that. That's where I drew my inspiration from. He owns www.wizarddesigns.co.uk and www.wizdforums.co.uk on which I am a modderator... it's a really fun place with a lot of talent visiting regularly.

Q2: The USB serves two purposes. First, it does supply +5V to the development board. Second, it is connected to an FTDI USB/Serial (COM) converter chip that the microcontroller can talk serial to, which it converts to USB, which is actually emulating a COM port. I can talk to the PC, but it's not a feature I'm using. I originally bought that dev board thinking that it was a USB programmer, but I was wrong. For my programing, I disconnect the touch sensor board and plug in the ICSP cable from my Olimex PG2C PIC programmer into the dev board. Then bob's my uncle

 

Really? Where? Another forum? I live on more than one, and so does this project. Arstechnica perhaps?

 

Looks nice indeed

 

Aha

Wahey! I just finished a USB LCD using one of those! I was amazed how tolerant it was of being soldered twice, and being bashed around a bit!

Using the serial is seriously easy: you can bodge lcdsmartie.sourceforge.net to send commands matrix-orbital style, and get you pic to respond like it should, (page 17 of this pdf.

ch424

 

Good tip! If I get stuck I might have to pull out my logic analyzer and serial monitor and reverse its commands, but for now I've got some .NET managed serial libraries I can use if I take that route (probably not on this project).


Here's the post I was talking about!
http://episteme.arstechnica.com/6/ubb.x?a=tpc&s=50009562&f=77909585&m=5980958165&r=5940931365

Pug goes by Infidel (we're trying to get it changed, but Ars charges $20 for name changes) on Ars.

 

Very nice. I really like how the electrodes came out. Are they really as rough as they look or are they really fairly smooth?

 

The one with uniform marks (all going the same way) is pretty rough, the rest aren't too bad. It won't matter with matte black painte and the goop to stick them to the front panel, it'll all look like smooth black. I tried polishing one of them up but it took forever and probably wouldn't have stuck to the plexi too well since there was no texture for the goop to adhere to.

 

Almost There!
The touch keys are almost done, very little left. Final integration will be when I install/assembled the new bezel. Laser cut parts are on there way from Oregon (mountain mods - ben kicks ass!) and are slated to arrive on wednesday of next week (the 30th). I'd expect to have a new update a day or 3 after that.

Keys prepared for having their bottoms painted


Thank god for the warmer weather, but I still have to heat the paint up - rustoleum satin black sitting in my laundry sink (the black thing is the washers' waste water tube) full of hot water.


Ready to rock!


Keys painted




Oh... that worked well - money shot (note no light leaking out the bottom now)


Death by electrodes?

The touch keys have to connect back to the QT150 somehow, so I've got to attach wire to my electrodes. The average soldering iron (and obviously not what I have - hakko 936) can't heat up a penny enough to solder to it... but a propane torch can!

Ready to solder - don't try this at home, kids. This is all the stuff I took outside to the concrete back porch. The wife would get kinda pissed if I burnt the house down, ya dig?


*Squints* look real close and you can see the propane flame. The bright side (pardon the pun) is that the solder burnt off all the crap on the penny - I had a feeling it would, which is why I didn't prep/polish them beforehand.


First one soldered - 24AWG stranded copper for flexibility


All 4 soldred with tails.


Even the shiny silver side wouldn't look real good amidst a sea of black which will be the front panel, so paint the tops of the electrodes. This won't alter the functionality of the QT150 as its a capacitive touch sensor, and is designed to have the electrode not in direct contact with the user interface.


Closeup of the paint drying on an electrode.


Car Key Gnomes?
Gotta attach the keys to the acrylic key backlight diffusers somehow... the answer - GOOP! I love this stuff! (Lick the q-tip, then pickup some goop, don't repeat!)


Small slot milled in key to accomodate the fact that the wires aren't attached dead center to the electrodes.


Slide the wire through the key


Apply goop...


Then push key down and embed into goop, keeping it as level as possible and centered in the indent.


4 keys - goop curing


All done.


all that remains is to put foil tape back on the keys (I removed it because it looked crappy with the painted foil tape) and install them into the bezel. I'll be leaving a 2 or 3mm gap between the top of the acrylic backlight diffuser and the top of the key so you don't see the foil tape's edges on the bezel... which is the other reason I nixxed the first round of tape.

Until next time!

 

nice work keep on going

 

Really good looking. Keep it up!

 

Wow

 

Very cool, thats sick dude

 

Thanks guys. Man I can't friggin wait to get the rest of the parts in for the bezel... if you think this looks good, you're going to crap yourself when you see the yet-to-be-painted bezel!

 

great project, love it, lucky i got my adsl now