This project is a collaboration between Jon Henry and myself. Jon has kindly hosted the site for the schematics and the calculators.
Jon also has the full breakdown on his application and the background to the project from his perspective on his site along with photos etc.
The task was to find the simplest way to decode a keypad constructed from an 'off the shelf' Matrix type keypad or a keypad constructed from Tact or similar type separate keys.
Two solutions are offered - the simplest being for the separate keys which requires no calculations and simply consists of a few resistors and a readadc at the PICAXE. This has been reliably tested from 8 through 20 keys. To use the same concept for the Matrix type keypad requires more effort in selecting the correct resistor values but this effort has been reduced for you if you utilise the 'ADC Keypad Decoder Spreadsheet' which can be found here. Jon's overview is Here. Both are on Jon's Website.
It seems that JON's WEBSITE is no longer accessible - SEE POST #10
The original thread with all the gory details of how we arrived at the endpoint is Here.
Jon also has the full breakdown on his application and the background to the project from his perspective on his site along with photos etc.
The task was to find the simplest way to decode a keypad constructed from an 'off the shelf' Matrix type keypad or a keypad constructed from Tact or similar type separate keys.
Two solutions are offered - the simplest being for the separate keys which requires no calculations and simply consists of a few resistors and a readadc at the PICAXE. This has been reliably tested from 8 through 20 keys. To use the same concept for the Matrix type keypad requires more effort in selecting the correct resistor values but this effort has been reduced for you if you utilise the 'ADC Keypad Decoder Spreadsheet' which can be found here. Jon's overview is Here. Both are on Jon's Website.
It seems that JON's WEBSITE is no longer accessible - SEE POST #10
The original thread with all the gory details of how we arrived at the endpoint is Here.
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