I have here a Lacrosse Techonlogy / StarMeteo WD-4103F weather station that had misbehaving user buttons.
I thus opened it in order to fix them which I believe I did well. Before putting it back together, I wanted to test it and because the battery older is not on the PCB, I decided to power it from my benchtop power supply. And that's when a bug occurred in my mind which somehow thought that two C batteries would be 6V.
The LCD was a lot darker that usual, but it seemed to work for a bit. Nothing smoked but by the time I figured my error, I believe damage was done to the "brains" of that board.
Now, when I power it with regular batteries (or 3V) it starts up, but seems to deadlock after a while as can be seen on that video:
I contacted the manufacturer support center but, unsurprisingly, they did not even reply to me.
Considering that the outside sensor can be read just well with an RTL-SDR and rtl_433, I have the project of changing the brains of the device, using the MAX32666FTHR board that I have sitting on my desk. It's a very low power device which is really appropriate in such a battery powered project, and because it supports BLE, I figured it could talk to one of the ESP32s that I already have around the house. This would make for this:
ESP32 gathers weather forecast from Internet and stores it, MAX32666 connects whenever it sees fit and displays it on the WD-4103F LCD.
I started my thought process by studying the main PCB which looks like this:
The row of pads at the center is what "touches" the LCD interface and so I would have to control it this way.
Having been allowed to use an X-Ray imager as an exceptional favor, I was able to see through the resin patch and this leads to this photo montage where I colored each track:
What's very interesting is that some LCD pads are connected together, and each have a test pad exposed onto which I could solder a connection wire.
My issue, and the object of my question, is how can I connect the LCD segments to the MAX32666?
I understand that LCDs require specific high voltage to operate but are there specialized low power chips that do this? And ideally a SPI or I2C solution because the dev board definitely does not have enough IO pins available for all LCD segments that need to be driven.
Many thanks in advance for any suggestion here.
