Realizator wrote: ↑Thu Aug 22, 2019 6:50 am
Stereomaton, your project is really great!
Thanks. People who have seen it in action in the preparing stages also like it.
The festival takes place in a few days and we hope it will be enjoyed by the public too.
Realizator wrote: ↑Thu Aug 22, 2019 6:50 am
I see you've used touchscreen connected to GPIO, and curious if there were any issues with it. I've played with non-touch TFT (mentioned
here), and it just works with no issues. I hope you will cover your screen connection and settings in your next report.
The next report focuses on the conception and realization of the case.
So (almost) no electronics inside.
The post you mention is one that encouraged me to try to add a small screen.
About its connections, there is almost nothing to say about: just insert it the way described in the documentation into the extension connector and it is finished.
We used this screen :
http://www.lcdwiki.com/3.5inch_RPi_Display
They provide a script which does a lot of things to "install" the screen. However, I do not like to execute things without understanding what they do, and after a quick read I saw that a part of it was not adapted to our usage. So I preferred to do it myself.
I checked their device-tree overlay file which looked fine, and just copied (and enabled) it on the StereoPi.
After that, a second framebuffer was available and the touchscreen device also appeared in the list of inputs.
The touchscreen is managed by a specialized chip on the extension board and is accessed via a I²C driver configured by the device-tree overlay.
Surprisingly for a resistive panel, the values are pretty accurate so that we did not have to calibrate it.
We wrote a small (ugly) python script to interact with screen and touchscreen by drawing directly in the (mmaped) framebuffer with
cairo, and by getting the touch events with
evdev.
So we did not tested it in a full environment, but as the low-level parts work out of the box, it should be good with high-level software as well.
Realizator wrote: ↑Thu Aug 22, 2019 6:50 am
By the way, if you have a blog, you can post a link to your original articles, and I will share this link in our Twitter too in addition to edited Crowd Supply article.
We only sent it by mail. We plan to add it on our website, but translated in French.
The differences with the submitted last version are mostly formal, in the structure, in the images/legends and in a few details; nothing very important though.