Start a new topic

Capacitive keypad on front panel

I'd like to add a capacitive keypad to the front panel.  I've got substantial electronics experience and have a CAP1298-based solution working for my outdoor irrigation controller, so I'm pretty confident I can handle the electronics side of things.  There's apparently a space I2C bus on the LCD board, so I should be good to go.


My issue is the (beautiful) printed graphics on the OpenEVSE front panel.  I'd like to add an overlay with the digits, etc, but since the graphics appear to be printed directly on the plastic it doesn't seem possible to easy modify the front surface.  I guess I could add an additional sticker on the "outside" surface, but that seems inelegant.  So question #1: has anyone had any luck modifying the front panel graphics in an aesthetically-pleasing way?  Option 2 is buying a new ML-58 lid from polycase, and starting from scratch on the graphics.  However, github is lacking info on the lid mounting features for the LCD (https://github.com/OpenEVSE/Enclosures/issues/2).  I can probably work around this by opening it up and reverse engineering the measurements, but maybe the nice folks at OpenEVSE could upload the manufacturing file and save me some trouble?  Question #2 is: does anyone know of a source to buy /just the lid/ for the ML-58 case?  Polycase will sell me a complete case, as mentioned before, but it's $36.34, or over $50 with shipping, which is a /little/ more than I'd like to pay for "just a new lid" -- especially since I've got two (and maybe eventually three) OpenEVSE boxes I'd like to do this mod on.


The STL files for the LCD mount and positioning jig have been uploaded to Github.



1 person likes this

I went ahead and bought the complete case from Polycase and got two shiny new clear lids.  I'm in the process of designing a little PCB which fits inside the lid and has the capacitive keypad.  I'm thinking of throwing an RTC footprint on there too, as one of my OpenEVSE boxes has one and one doesn't.  I'm sure I don't /need/ it, and it would probably be easier just to buy the DS3231 module from adafruit, but...

Anyway, I can always leave the footprint unpopulated if it ends up being too much trouble.


I was going to use a CAP1298 touch sensor IC, which I've used in projects behind plastic lids like this before, but I think I'm going to try the AT42QT2120, which looks better suited to a matrix keypad.

 Just wanted to report back on the mod, which was a success.  I even did a "version 2" and integrated RFID behind/around the display.

image

image

image

Happy to share more details if folks are interested.

I posted the project on hackaday and put the design files up on GitHub.  I might try to fabricate a batch of a dozen or so boards; if you'd be interested in buying one contact me (email address at the bottom of cscott.net).

Login or Signup to post a comment