# sea of keys encoder

#### inglewoodpete

##### Senior Member
Amazing, just amazing!

#### Jeremy Leach

##### Senior Member
Hi Wilf, this is really impressive stuff and worthy of everyone taking a good look at your hard work, as there's a lot to learn from this too.

I've grasped it now after a couple of reads. I think you've got you Q numbering mixed up in the second para in the ENCODER section ??

I'm still chewing it over though. I think perhaps an additional couple of diagrams would help, to give an example of a single key press, showing the resistor ladders as ladders etc. Might be easier to get the head round.

I actually found the concept easier to understand when I got to the touchpad example. (By the way, where do you get that resistive material? Would be great to experiment with!)

Also, with your touchpad code, do you really needs lines 19 and 25?

And ...what sort of resolution do you get with a touchpad like this??

Seriously good write-up and idea though.

Edited by - Jeremy Leach on 15/11/2006 12:55:28

#### Jeremy Leach

##### Senior Member
I don't normally do this, but am posting to raise this to the top of the stack - I'm wondering if people have missed this excellent piece of work..?

#### Dippy

##### Moderator
I agree. Great stuff and a lot of hard work. But you can't keep it the top or you'll end up with a thread longer than Deadleyfoez's.

#### wilf_nv

##### Senior Member
Hi all,

I appreciate the feedback.
Thanks to the keen obervations and comments from Jeremy, I have corrected the transistor labels and (to make it easier to grog the basic concept) I have added a simplified 08M encoder circuit showing an example key press.

The touchpad I tested was made with two semiconductive plastic strips removed from high voltage cables. I am also experimenting with a flexible conductive polymer paint.

Four wire touch screens are available here:

Typical resistance of these tranparent panels is 350 ohms/sq which requires that both ends of the x/y layers should be driven by transistors.
The resolution of most touch screens is 4096x4096.

wilf

#### jodicalhon

##### New Member
Didn't miss it, Jeremy - just packed it away for future reference (after a quick once over), like I do with any of Wilf's stuff I come across. It always contains clever ideas, often in deceptively simple packaging.

This encoder already has me thinking (probably very dimly!) of ways in which I can use the basic idea.

Cheers.

#### Bloody-orc

##### Senior Member
there should be a sticky forum of all the good and completed and documented project such as this...

#### Rickharris

##### Senior Member
Sticky? Most things would be in it

#### Bloody-orc

##### Senior Member
no. only well documented and summed up projects with examples (if needed) etc. like there was a rtwi (real two wire interface) and this one right here.

#### thelabwiz

##### Senior Member
I have about 50MB of unused disk space at www.picaxe.us
Maybe add a section called &quot;PICAXE Community Designs&quot;?

John

#### RickAlty

##### Senior Member
Fantastic, Wilf. I already have an app in mind for it

Richard

#### slurp

##### Senior Member
The usual answer is to book mark these pages for reference and remember them when chatting on other forums... if you've got a website give it a link in a suitable location.

Done the first part, second will follow shortly

Best regards,
Colin

Â

#### Mycroft2152

##### Senior Member
If anyone is interested in some of Wilf's non-PICAXE circuits, showing the same amazing creativity and understanding of electronics, check out his folder on the Yahoo BEAM robot group.

http://tech.groups.yahoo.com/group/beam/files/wilf_nv/

You'll find 200+ circuits there. Many of which could be used as the 'front end' for a PICAXE based design.

Myc Holmes

Edited by - mycroft2152 on 20/11/2006 12:30:45

#### eclectic

##### Moderator
Wilf. You're a genius mate.

My touchpad was delivered an hour ago.

Click! It works!

Many thanks.
e.

#### Bloody-orc

##### Senior Member
ARGH! i hate that damn yahoo. it NEVER works when needed (or not needed). why do you guy's like yahoo groups so much? use google instead. googlepages or something like that. much easier to use

is there a way i could see the touchpad project without using yahoo? could someone copy it for me and send it to rellermaa &#228;a gmail duut com

Edited by - bloody-orc on 21/11/2006 15:29:29

#### toxicmouse

##### Senior Member
yeah, i am really intrigued by this touchpad but i can't get onto yahoo tech groups either.

#### eclectic

##### Moderator
Orc and Toxic

I didn't use Yahoo.
The project circuit and program are IN
Wilf's posting of 18 Nov 09.18
e.

Edited by - eclectic on 21/11/2006 16:05:33

#### Mycroft2152

##### Senior Member
There is a link to Wilf's keyboard project in his first post on this forum. Somebody forget to read the post?

The Yahoo group's link is for some NON-PICAXE circuits that Wilf has done over the years for the BEAM Robots group. Amazing and clever stuff!

Yes, you need a Yahho ID to enter the site. Not a big deal, it's a freebie. There are thousands of special interest groups there. (even a few for PICAXE) You can even create your own group.

Groups are important, they act as central archives for ideas and designs. When posting to tinypic or any other generic site, these posts are lost in the fog.

Anyone try to google the contents of a tinypic link? Anyone ever check how long the tinypic link is valid?

I really don't understand the reason for the complaints. You readily accept this forum's poor format (there is a sense of pride in doing ASCII art) and limited capabilities, for it terrific content. Yet have a problem with signing up for a free account.

It's truly unfortunate, but you are missing out on a lot.

Myc

#### wilf_nv

##### Senior Member
Hi Myc,

Thanks but no thanks, at least not here.

I would really like to concentrate on the technical merrit of the PICAXE as used in this project without OT distractions.

Start another thread on that important topic.

wilf

#### eclectic

##### Moderator
Wilf.

I should have clarified my earlier posting.
My new (ebay.co.uk) touchpad is an

8- wire 10.4&#8221; diagonal. (&#163;15 inc.)

Your program and circuit work perfectly, using
just the four SENSE connections.

I&#8217;ve simply modified the X-Y values to accommodate
a set of printed backing sheets.

Thanks again.

e.

#### wilf_nv

##### Senior Member
My pleasure Eclectic!

Just for interest, what is the terminal to terminal resistance of your touch screen?

wilf

#### eclectic

##### Moderator
Wilf.
Some approximate values;
All in Ohms, measured on Sense pins.

T-B ~ 350
R-L ~ 390

B-L 320 (0,0) &gt; 780 (top-right)
T-R 780 (0,0) &gt; 320 (top-right)

e.

#### Buryboy2000

##### New Member
eclectic, What did you put in to get the touchpad from ebay? I can't find any!
Cheers
Oli

#### eclectic

##### Moderator
Oli BB, try

http://cgi.ebay.co.uk/10-4-Resistive-Touch-Screen-LCD-95646-DYNAPRO-NEW_W0QQitemZ290059250986QQihZ019QQcategoryZ96893QQrdZ1QQcmdZViewItem

11.99 + 3.99 pp
Price increased &#163;1 from last month. Perhaps