Could you please give me a kickstart on how to make use of this old alarm keypad respectively how to start reverse engineering?
The module on the top is an 2-line LCD display with background light. The module underneath is connected to a keypad.
Together with esphome I definitely want to make use of the keypad and if it’s possible of course of the display too.
My first guess: I would need to get rid of the bottom module as it runs on 12v. I don’t know how to deal with the keypad itself as there are more keypads than lines going to the bottom module. So I guess there’s some kind of matrix connection going on?
The easiest way would be to completely remove the components you want to use from the original circuit boards and then wire them to an ESP running ESPhome, throwing out the old circuit boards. There are ESPhome components to drive LCD’s and methods to use matrix keypads.
@myle i already looked them up, but thanks to you the name “character” caught my eye and I now know, what an character based lcd display is and that it exists shouldn’t be to complicated to make use of it.
@sparkydave thanks to your link I digged a little deeper and know now what I need to identify the keys.
Btw for the character lcd display there are pins 1-14 and on the left side pin 15+16. These pins are for backlighting, right? Is there a rule which one is ground and which +? Don’t want to break it.
And do you have a clue what kind of connection I would get from the blue connector in the corner? Seems like it is for programming, but can it be further determined?
The pinouts on those are generally generic so you should be able to find a pinout for it very easily. I haven’t played with one for a long time so can’t remember the details. You can however get circuit boards that allow you to send a data line to it rather than having to wire many ESP pins to the display.
No idea about the blue connector. We can’t see the brand or model of the keypad… short of googling the numbers on those stickers. Like I said, I would ditch the entire circuit board and simply reuse the components you want.
shouldn’t be to complicated to make use of it.