Hi! In 2017 or so I bought a 7" official RPi touch screen, and it has served me well, except that touch stopped working. Note that I use lcd_rotate=0 in config.txt – for what I use it for, I prefer the display to lie more horizontal. So when I speak of “the bottom pixel row”, I really mean the bottom row as the manufacturer of the display intended it. For those who use lcd_rotate=2, please think “top” instead of “bottom”, “left” instead of “right”, and so on.
What happens on my touch display is that touch only works in the bottom-most row of pixels. Anywhere else on the screen, my touching, tapping, holding is ignored; but in that bottom-most row, it works fine. As if scanning the Y coordinates had stopped working, but the scan along the X-axis still worked fine.
I re-seated the small FPC connector on the display controller board but did not dismount the board from the screen, as I understand the wide FPC connector on its back to be related to display only, not touch detection.
What else should I do before declaring the display (or at least its touch function) unsalvageable?
Its a long shot but I’d reseat the cable going from the display board to the DSI connector on the Pi. I’d redo both ends. The touch goes to the Pi via the DSI cable along with the video thats going the other way.
Ok, just wanted to confirm that it wasn’t maybe a software issue. I have one of the original version 1 touch screens. I’ve had it for quit a while. My only issue is my bezel has slowly over time succumbed to gravity and slid down. I managed to slide it back up, but have a bit of screen at the bottom that has glue residue on it. Its a bit distorted and fuzzy. It looks dirty / smudged. The touch still works in that area though. It’s currently connected to a Pi 3B+ running Buster.
Other than this little touch issue I am happy with the screen; knock together a case for the back, and there’s room for a really large battery and, say, a motor controller together with the Pi. Mobility and real-world sensing and control, perfect!
Thanks for your help and for figuring out what isn’t the problem. Now at least, I can go get a new display with a clean conscience. :)
Very nice rig! I confess that in place of clamps and “open beam” (is that a product name? a quick search finds nothing but houses with pretty wooden beams) I generally trust in gravity and a tabletop large enough that nothing lives dangerously close to the edge :)
Regarding your tip regarding the SmartiPi 2 (much appreciated!): it seems they even provide four extra mounting holes on the back panel. For, you know, extra batteries and stuff. This case goes on the to-buy list, and I owe you another big thank-you!
(If this posts twice, I apologise; the first posting seems to have gone off to the beach or something.)
Clearly I must do less programming and more looking into standard parts. I know rudimentary machining (drill press, lathe, mill, and CNC work centres), and while this is fun, prototyping builds would be much less work.
Not to mention that I am an utter moron: I was already thinking about building a mount to attach the SmartiPi 2, via those four extra holes, to a wheelchair. It was only when you wrote “VESA” that I thought about ready-made monitor arms … embarrassing but there we are.
I may still have to build – gaze-tracking requires that head, headrest, screen and tracker move as a single unit as far as possible. But a monitor arm may be good enough, and if not, it still is much easier to prototype different positions for display and holder.
With the extra bits I had left over I made a laptop stand and monitor stand. I wanted to lift my laptop up a bit to get good airflow underneath to help it stay cool out on my deck. I also have a USB monitor I plug into it that I didn’t like the stand it came with, so I made my own.
What surprised me was so far I’ve only had to cut two beams. There is bigger diameter stuff out there too. And hinges, motor plates, servo plates etc, etc.
