SparkFun Forums

[newbierobert]

i am newbie

using a 4x4 kepad would like to log all keystroke to an eeprom so it could be later retrieved

what do i need...where could i get more info pls help
thank you

[newbierobert]

pls some one just need at least ur input ( what do i need)
basic stamp with eeprom and
a keypad encoder should that do it
it has to be really small
thank you

so could get started thanks again

[leon_heller]

You don't need a keypad encoder, a 4x4 keypad can be handled with minimal hardware on a suitable MCU with eight I/Os. Not really a beginner's project, though.

Leon

[newbierobert]

can someone show me examples or links pls it would really help thanks

[riden]

Scanning a 4 x 4 keyboard in software is not difficult and you can add a serial EEPROM chip like an Atmel 24C128 (16k) or 24C256 (32k) to store your keystrokes. Your requirements are well within the capabilities of all but the most basic microcontrollers. If you can dump the stored keystrokes via the serial port to a PC, then all you need is a processor with 10 IO lines plus the serial connections and 2k of program space (estimate).

A BASIC Stamp would work and probably meets your size requirement. Kronos http://www.kronosrobotics.com has similar chips that I know will work, but you would need to supply your own board or buy one of theirs.

SparkFun carries a number of boards that would also meet the requirements. They are inexpensive and very well made and provide greater expansion opportunities and flexibility. The tradeoff is that the learning curve is a bit steeper and you would need a PIC programmer or a chip with a bootloader built in so you can download your program. You would also need to choose a development environment (C, BASIC, Assembly, etc.) to write your program.

[riden]

can someone show me examples or links pls it would really help thanks

Google
"Basic Stamp" matrix keypad
PIC matrix keypad
PIC serial EEPROM

to get started.

[newbierobert]

do you have any site with examples (keypad scanning)or boards that will give me an idea for what to buy.....thanks again much app. the programing is fine for me with C but the hardware is what bugs me thanks again.....

[dext3r]

What is your intent for this device?

4X4 keypad...storing numbers....thats all?

Not to sound negative here, but it sounds to me like you could be trying to build an ATM keypad spoofer...

[upand_at_them]

Nah, probably just a homework assignment.

Let's see the work he's done so far. How about a flowchart? An outline? Some show of work?

Mike

[chromatech]

i agree with dext3r.

sounds like an ATM spoof.


regarding how to do it read read read!
and google.