The ADC Keypad


New Member
Hello gents

Some of you had been following the progress of the 'one input keypad'.

Im here to say weve come to a great working solution. The circuit is so easy to build and adapt to different numbers of switches.
The code, well the code is ridiculously easy.

<A href='' Target=_Blank>External Web Link</a>

Ive posted the final concept on its own page of my site with a link on it to the old page with the first concepts to where we are now.

Early on in the project, BeanieBots suggested an equation that, at first, wasnt feasible due to the circuit but in the end became the basis for the final equation. Id like to thank him for his input.
Premelecs suggested circuit was used as a jumping off point for the final circuit. Thank you Premelec.
The final concept was a collaboration between BCJKiwi and I. He provided invaluable expertise and testing. Its been a pleasure thus far working with him and I hope we can work together again in the future.

Ive been working with the picaxe for almost a month now. It is my first run into programming. Im a tinkerer by nature as Im sure alot of us are.

Ive seen beginners go into forums to ask questions and get responses like 'learn the stuff before you come in here' or 'are you stupid, you cant do that'. I must say I have not seen even an inkling of that here. The users here seem to have a mentoring attitude, not a diety one. They like to help. These forums have made my experience thus far with the Picaxe system outstanding.

Id like to thank everyone on these forums for being so helpful and courteous.


New Member
Most excellent project that I'm sure will be useful for many on us, great work and thanks for sharing your results with us.



Senior Member
Thanks Jon Henry and BCJKiwi - great work.
I am very close to doing the same thing in a project of mine, so very grateful for the shared info. It means I will not have to reinvent the wheel.


Senior Member
As confirmed in the first page of the Excel SS &quot;It has been successfully trialled in the range of 8 through 20 keys&quot;

This was done with a 14M at 8mhz on a breadboard using standard 1% 10K and 1M resistors in the &quot;Divider chain with Pullup&quot; arrangement. This is the same arrangement that Jon is using with a 40X1.

The Matrix keypad has not been tested but uses the same core concept and theory and the spreadsheet confrms the functionality. However a bit more work needs to be done as the resistor values are different for each switch and the characteristics of the higher resistance contacts in these keypads needs to be taken into account when selecting the resistor values to use.


Edited by - BCJKiwi on 29/08/2007 09:08:36


COOL ! <img src="smile.gif" width=15 height=15 align=middle>

This is the picture of that? <A href='' Target=_Blank>External Web Link</a>

have you one &quot;finished sample&quot; picture?