What I’m working on now: Raspberry Pi Touch Display

Intro
I’ve been waiting for a decent, inexpensive display for the Raspberry Pi and now they make one. http://www.mcmelectronics.com/product/83-16872 I’m one of the lucky ones – I got one before it was put on backorder! Anyway it’s just $60 plus shipping.

Power
The jumper wires can be used for power. I initially connected it that way, but the supplied wires have nowhere really safe to rest so it seems extremely likely to bend a pin. Too bad they didn’t supply right-angle jumper wire connectors, if such a thing exists. (They do not.) But you can also do USB out from the adapter board to micro-USB in on the Pi. That’s little better. I bought a 6″ micro-USB cable from Amazon and now I use that. But boy that’s a really, really tight fit. You’re as likely to break the display and the Pi due to the tension as you are to succeed in getting them connected. I pre-bent the connectors to make it work. Another inch to work with would have been ideal.

Virtual keyboard
Apparently
$ sudo apt-get install matchbox-keyboard
will install a virtual keyboard. I realized the thing wasn’t as portable as I had hoped as long as I had to have a USB keyboard attached! But the little virtual keyboard is really hard to use.

Touchscreen
I find the touchscreen really hard to work with to control window sizing. And although their specs say it’s 800×480, it doesn’t come up that way, so you really don’t have much display area in fact. It comes up as 752×448 and the launched windows seemed cropped at the bottom. If you change a window to full screen then it’s OK however, but even at full size it just doesn’t feel that large. See below to get the full 800×400 display operational.

The edges are really hard to tap with even slender fingers. Someone suggested a capacitive pen – that would probably work a lot better but I don’t have one to test with.

In general accurate tapping is kind of hard. For instance an X-window has three little icons in the upper right corner – minimize, maximize and close. It’s hard to tap the one you want – I get it wrong most of the time.

Display is smaller than the monitor
This has bugged me for over a year and I finally found it. This happens due to overscan being on. I doubt overscan is needed for most modern displays. So just go into raspi-config’s advanced options and disable overscan! Then your display will be 800 x 400 from now on.

Application idea – visual alarm
I’m thinking of creating a “visual alarm.” This could gently wake me up at night for problems at work, by turning on the screen and displaying an alternating light/dark pattern. This will be another post if I ever implement it.

Conclusion
My initial enthusiasm at the idea of a portable display designed specifically for the Pi was dampened by my actual experience with one. I was hoping for a 10″ display – better for educational purposes. The user experience with this display might be a lot better with a capacitive pen.

References and related
Useful Raspberry Pi touch display setup guide.
Four Pi display.
Have no display whatsoever for your Raspberry Pi? I show a way to work with it under even those circumstances. In fact that is what I mostly do.

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