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General Category => Your projects => Topic started by: roneeron on October 23, 2011, 02:36:07 AM

Title: Touch Pad Replication
Post by: roneeron on October 23, 2011, 02:36:07 AM
Hi,

Here is my rep of the ten  touch pad...original at...

http://www.pcbheaven.com/circuitpages/10_buttons_touch_pad_bcd_output/

First off I am not that great with double sided PCB's so made two boards and stuck them together with crazy glue. I used PCB pins to connect the two boards

The head on the  pcb pin is just .015 inches high and so I had some .017 thick brass so put pads on the pads and soldered them down. This made a level playing field, lol

Initial tests showed that even a piece of paper in contact with several pads caused glitches, so I made a mask from 1mm cardboard to raise the photo paper numbers up off the pads and leaving a .5 mm air gap between the photo paper and pad. On top of the photo paper is a 2mm piece of glass.

The pic flashed with my R1301 from CanaKits...

http://www.canakit.com/usb-pic-programmer.html

Just using a 7447 BCD decoder

I was having  some erratic numbers until I put a metal plate behind the 16F1937 then every thing works fine!!!

Video up...<http://www.youtube.com/watch?v=z2ef7IBriwA >

Ron


Title: Re: Touch Pad Replication
Post by: _pike on October 23, 2011, 11:02:51 AM
Nice job !!!!! Keep going.....  ;)  But may i ask why did you buy the "Mini USB PIC Programmer" where its price is so expensive, instead of buying a pickit from microchip with the same amount of money????
Title: Re: Touch Pad Replication
Post by: kam on October 23, 2011, 13:38:57 PM
Ron, you've done a very nice job, and as i see from your video, it works pretty fine. You've seen yourself how difficult it is to design the touch pads, so that they work find. You can change their sensitivity by changing the values of PressThreshold_H:PressThreshold_L constants, if you wish to use thicker or thinner touch-pad covers. Where are you going to use this?

Thank you for maintaining my signature on your PCB and also for the credits you gave me in your video. Much appreciated.
Title: Re: Touch Pad Replication
Post by: roneeron on October 23, 2011, 17:48:09 PM
Nice job !!!!! Keep going.....  ;)  But may i ask why did you buy the "Mini USB PIC Programmer" where its price is so expensive, instead of buying a pickit from microchip with the same amount of money????

Thanks!

Well yes, I did get screwed. I live in Victoria Canada and Canakit is 40? Km's away in Vancouver. I bought the kit at $35.  The PicKit2 from the states would be $38 plus shipping. If it comes UPS I pay
from 20 to 50 dollars, then at the door the bandits want another 20 dollars "brokerage fee"

But Canakit charged me 25 dollars "freight" and then sent in by mail for $2.20 and it took two weeks to travel the 40 km's...not too happy, Kind of in between a rock and and a hard spot on on this.

Ron

Title: Re: Touch Pad Replication
Post by: roneeron on October 23, 2011, 18:00:44 PM
Ron, you've done a very nice job, and as i see from your video, it works pretty fine. You've seen yourself how difficult it is to design the touch pads, so that they work find. You can change their sensitivity by changing the values of PressThreshold_H:PressThreshold_L constants, if you wish to use thicker or thinner touch-pad covers. Where are you going to use this?

Thank you for maintaining my signature on your PCB and also for the credits you gave me in your video. Much appreciated.

Thanks Kam, I changed a few things and still had it work. So your design is fairly robust. But no plan for it yet, just a learning experience. I marvel at your code writing!

Credit where credit is due, isn't that the way it should be?

If I made another one I would go 12 pads, a decimal point and an enter pad.

Ron