Cardputer usage warnings and a question about its LCD connection

  • I just received my Cardputer and an extra M5StampS3 1.27 along. From the photos it seemed that the device consists of a base module and an M5StampS3 plugged into it. This suggested that I could have several apps preprogrammed on the M5StampS3-s which I could plug into the base interchangeably rather than reflash it. I like this sort of modularity in my projects.

    Although this concept is not fully wrong, there is a big caveat which was not obvious from the images and documents. Namely - besides the pins plugging into the base, the MCU is also connected to the screen on the base via a small ribbon cable. This means two things (worth being mentioned somewhere in the descriptions of the devices):

    1. An accidental jerk during an attempt to take the M5StampS3 out of the base will easily damage it beyond repair. This is what happened to me now, as I was presuming the MCU was only being held by the pins and was not taking care to avoid the jerk when it came out.

    2. The MCU has a dedicated connector soldered on the back, which is not present in the M5StampS3 that you can buy separately from the store. You would also need to find and solder the right connector.

    Having gotten the warnings out of the way, I now have two questions, which, perhaps, someone here could answer:

    1. Where could one buy just the screen (with its ribbon cable) separately?
    2. Where could one get just the connector for that ribbon cable to solder onto M5StampS3 1.27?

  • @konstantint The connectors are commonly available on amazon are are not fitted by default so that screws can be soldered direct to the stamp or the stamp soldered flush to the PCB.
    The Screen is an ST7789V2
    While I can find many square screens based on this chip, I cannot find any 1.14" versions of it (also used in the M5Stack colour LCD Unit)

    What do you "damaged beyond repair"? did you rip the ribbon?

  • Thanks for the answer! Could you point to some part number of other identifier to help find the connector?

    What do you "damaged beyond repair"? did you rip the ribbon?

    I'm not 100% sure. The thing that visibly broke at first was just the connector (it didn't hold the cable anymore), so I had to solder the contacts on. I made sure the right spots on the PCB beep through to the appropriate pads on the ribbon (and there are no shorts among them) but the screen shows no picture (while powering on the backlight) - as if the ribbon were only sending through the power, but not the data. There's no visible rip in the ribbon, but there's one reasonably strong bend right next to the connector. It was there originally (the ribbon is packed by sticking it to the back with some kapton tape) but I'm afraid the un-bending it backwards could have damaged one of the thinner lines inside it. In any case I have no idea how to fi it. I didn't bother checking the connectivity all the way to the screen, as the ribbon disappears into the body there and seems pretty fiddly to disassemble, at least at first glance.