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success with a cheap Chinese touchscreen
Sunday, February 7 2016
On my firewood-salvaging foray today, I did my best to cut down a mid-sized (9 inch dbh) skeletonized Chestnut Oak a little uphill from the Stick Trail four or five hundred feet south of the Chamomile. It was already leaning against some other trees, a condition the first cut failed to reverse. After the second cut, it was still leaning on those trees, but it was now almost vertical. I can probably come back later with a rope, get a rope cinched around it 12 or 15 feet above the ground, and then just pull it over. Despite not being able to fell most of the tree, I still managed to cut enough wood from the bottom part of the trunk to satisfy a couple salvaging forays.
I spent much of the day trying to get a cheap Chinese ($25) touchscreen HDMI LCD working with one of my Raspberry Pi boards (I have two and they are both Model Bs). I was using hookup wires to attach the display to my Raspberry Pi before realizing that the two were designed to simply plug together. This was convenient for testing, though there is no way I would deploy it this way in a final system. Doing so would hide away a bunch of GPIO pins, particularly those belonging to the ever-flexible I2C bus, and I would never want to cut off my ability to interface with that. (This is also the reason I take a generally dim view of "shield" boards for Arduinos, since they also tend to bury pins that would otherwise remain accessible.)
The touchscreen eventually just started working; perhaps all I had to do was enable the Raspberry Pi's SPI interface. It still desperately needed calibration, and I found a page that was helpful for that, though it failed to mention that the recommended calibration software will not work at all if one is logged in as a superuser. I also needed to tweak the settings in /boot/config.txt so that the Raspbian UI would use the display's entire 800 by 480 pixel array, and that page was helpful in making that happen as well.
Ultimately, though, the plan is to make a device that will serve as a network-attached music player client. I've had the dream of making such a device for years, but I've always run into problems: slow hardware, insufficiently-small screens, clunky software, and flaky networks. Most of these problems have been solved, but I still haven't found the perfect software. In recent years, I've been happy with XBMC (now Kodi), a UI designed to find and play media. Perhaps it would work on a tiny screen as a system for finding and playing music. There are a number of Linux distributions with Kodi as a frontend, but they have rather limited Linuxes undergirding them (for example, there is no package management or even the ability to change the root password in OpenELEC), and in any case I couldn't get the touchscreen to work with the several I downloaded. Kodi can also be installed on top of Raspbian Linux, so I tried that too. But the touchscreen depends on the X.org windowing system, which Kodi completely bypasses (it uses its own graphical framework). It's looking like I'm going to have to find some music player that works well on a tiny screen and can be launched from Raspbian.
This evening Gretchen requested that I make dinner, so I made rigatoni pasta with red sauce containing mushrooms, onions, garlic, and seitan. Also, unusually, I made a simple salad using a tub of mixed greens and the first dressing I found in the refrigerator door. Salad is not something I care about, though I will eat it when it's in front of me.
Another thing that I don't care much about is the taste of our household water, which often becomes unpleasantly metallic after winter rains. In the past, Gretchen hired a water quality expert named John to test our water and then, ultimately, install an oxygenator to eliminate iron. But clearly on a periodic basis something else becomes wrong with our water as well. It has been so bad that in recent years Gretchen has tried to re-contact our water guy, though those attempts always failed. Yet now she's thinking we should try something else; Susan and David had been using John but recently decided to fire him after his recommendations failed. In response to Gretchen's question tonight about what we should do, I suggested we get a sample of our water when it's tasting bad, ship it to some place to have it tested, and then, based on the results, Google possible solutions that I could then install. After you get your results, the problem becomes a research and plumbing job.
For linking purposes this article's URL is:
http://asecular.com/blog.php?160207 feedback
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