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Clock and data...

starion

Oct 13, 2011
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Oct 13, 2011
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I'm really losing it in my old age. :confused:

I have a project in which I need to read clock and data outputs from a keypad.

I've forgotten how this works and the basics of clock/data. Can anybody re-educate me or point me to a simple tutorial/explanation?

Sorry to be such a noob, but it has literally been years since I've used it, and too much beer in between...
 

MrEE

Apr 13, 2012
84
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Apr 13, 2012
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You need to cut down on the beer... just kidding.. I like it too. Well of course you can start by Googling :) but here is one place to start: http://www.computer-engineering.org/ps2protocol/
Notice that you must have a PS/2 based keyboard (same as keypad??) fot this.
Let us know how do you plan to read the data? what is it you want to accomplish?
 

starion

Oct 13, 2011
3
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Oct 13, 2011
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Cut down on the beer? I'm giving up electronics and programming right now.

Seriously though, it's a security keypad/prox reader. Basically 5 wires, +/- 12VDC, Clock and Data, and a tamper.

My goal is to read the data and transmit it via a network (probably UDP). My software will then handle the rest. But I need to start at the beginning and understand all the steps first.
 

starion

Oct 13, 2011
3
Joined
Oct 13, 2011
Messages
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So the next obvious question is:

Is there a chip/platform/basic stamp that I can just feed the clock and data into and output UDP to ethernet?

(Can you tell I've been doing software for more years than hardware at this point?)
 

MrEE

Apr 13, 2012
84
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Apr 13, 2012
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84
there are all kinds of options/solutions depending on your skills and background. It seems that most people want the fastest and easiest way with minimal HW design. This is fine as there is a lot of information available. One very popular and easy to use platform is an AVR based board called Arduino. It is a general purpose microcontroller development platform with tons of info available. These come in a variaty of complexities but I think all you need is the simplest one. Just google the following:
AVR, Arduino, Atmel, AVRFREAKS.
Here is a few thoughts to get you started:
1- make sure the data and clock are 5V compatible, if not you'll need to convert the levels from 12 ot 5V.
2- Most AVR's have a SPI (serial peripheral interface) that yo ucan set up to read clocked data from your keypad.
 
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