Jeff Duntemann's Contrapositive Diary Rotating Header Image

January, 2013:

The Raspberry Pi Keyboard Stutter Problem

When I first cabled up and ran my Raspberry Pi board, it worked like a charm, first time. I was powering it with the Motorola Droid X2 charger that I had stolen from the kitchen desk upstairs. To keep peace in the valley, I went out and bought a cheap Micro-USB phone charger at Best Buy. It booted normally, but then, when I tried to log in, the keyboard began repeating characters. I’d type in “pi” and see a parade of extraneous i’s march in stately fashion across the display:

piiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

Needless to say, I couldn’t log in. Now, this didn’t happen every time, but probably half of all logins I attempted failed, with the same keyboard jitter. I tried two other USB keyboards I had on the shelf plus the known-good one attached to my GX620 USFF, and saw exactly the same behavior. It clearly wasn’t the keyboard itself. I’m using a Dell SK-8135 keyboard, which has a 2-port USB hub to which a Dell USB optical mouse is connected. This leaves one USB port on the RPi free, with any luck to use for thumb drive add-in storage. More on that once I figure it out.

Anyway. Some googling suggested a power supply shortfall. I got out my DVM and put the probes on test points 1 and 2. These are minuscule “doughnut” pads on the RPi circuit board. One is labeled TP1, the other TP2. Hunt around on the board for them; it’s not like there are a lot of square inches to search. TP1 is located next to the 220 uF filter cap at the Micro USB jack. TP2 is right next to the yellow RCA jack.

The RPi is designed to work at 5V. Anything much below that and things may start getting flaky. My reading across the test points was 4.72V. Aha! We now have a new phone charger for the kitchen desk–a cool one with a retractable cord–and I decided to dedicate the old one to the RPi. With the original Motorola Droid X2 charger in the wall, I measured 5.03V across the test points. Shazam! No more keyboard stutter.

I’m not sure it’s a question of the RPi drawing more current than the charger can provide. The Droid X2 charger that works is rated 850 ma. The no-name charger that provided only 4.72 volts is rated 2.1 A. Current sourcing ability is important, especially since different USB keyboards and mice draw different amounts of power–but accurate voltage is just as important. I’m guessing it’s sloppy voltage regulation in the cheap charger. If you’re getting keyboard weirdness, put your DVM on the test points and see what your charger is feeding the RPi.

What? You don’t have a DVM? No Pi for you!

Odd Lots

  • From the “…And Then We Win” Department: Lulu is eliminating DRM on ebooks published through the site. (I was notified by email.)
  • The Adobe CS2 download link everybody’s talking about (see my entry for January 10, 2013) is still wide-open. If it was indeed a mistake, you’d think they would have fixed it by now. New suggestion: They’re arguing about it. New hope: They’re really going to allow CS2’s general use without charge.
  • I didn’t get the art gene from my mother, but I did indeed enjoy the Museum of Forgotten Art Supplies. I still have my full drafting set in a drawer somewhere, replete with bow compasses, French curves, triangles, and so on. How many years will it be before nobody under 50 has any idea what those are? (Thanks to Jim Rittenhouse for the link.)
  • And while we’re doing peculiar museums, check out this selection of implements from the International Spy Museum. I believe the surplus houses were selling CIA turd transmitters twenty or thirty years ago. Shoulda bought one when I could. As the late, great George M. Ewing would have said: “Forget it, Jeff. Nobody will pick that up.”
  • Strange transmitters you want? From Bruce Baker comes a video link that no steampunker will want to miss: The annual fire-up of the only Alexanderson alternator left in the world, station SAQ in Sweden. From the sparks to the swinging meter needles, it’s just like Frankenstein, only it’s real–and sends Morse telegraphy at 100 KHz or so. No vacuum tubes, and I don’t see any reason why it couldn’t have been in operation in 1890.
  • Every wonder who was behind Information Unlimited? Here’s the guy.
  • Here’s more on how fructose messes with your brain. It’s not just the number of calories. It’s the chemical composition of those calories. Whoever says “a calorie is a calorie” is wrong, and probably has an agenda.
  • It’s almost pointless to link to the first video ever made of a giant squid (since we won’t see the whole thing until January 27) but Ars Technica has a background page that’s worth reading. “Hello, beastie!”
  • The BMI is worse than worthless. But I told you that years ago.
  • Brand fanboys may have low self-esteem. Or they may just be tribalists. Or tribalists may be people with low self-esteem. No matter: Defend no brand but your own. Big Brands can damned well defend themselves.

The RPi Enthroned

I wonder how many Raspberry Pi boards will spend their entire working lives sitting cockeyed on a desk somewhere, at the center of a tangle of cables. That’s how mine was until a couple of days ago, when despite my cough I allowed myself a few minutes of quality screwdriver time to pull a proper RPi system together.workstation-500wide.jpg

It didn’t take much. Mostly what it took was a 2004-era Dell SX270 all-in-one system minus the SX270, which I now use as a bookend. The key component is a heavy stainless steel base with a VESA monitor mount and a bracket to hold the SX270 behind the monitor. The monitor itself is an unexceptional Dell 1704fp, with a native resolution of 1280 X 1024. (Those now sell for ~$50 on eBay.) That’s more than enough pixels for an RPi, although I tested it on one of my 21″ 1600 X 1200 behemoths and the little gadget did quite well overall.

BackView-500wide.jpg

I had already mounted the board on an aluminum plate, and all I had to do this time was drill two holes and bolt the plate to the SX270 mounting bracket. I may dress the wires a little to keep them from placing any torque on the connectors, but it works well as-is.

I was surprised to find out that the MagPi magazine is actually laid out on an RPi, using the open-source Scribus layout program. I installed Scribus via apt-get and poured some text into a layout. (I’ve been playing with Scribus for years.) Brisk! I guess we need to stop boggling at the capabilities of tiny little computers with all of two ICs on the mobo.

It certainly does a good job with FreePascal and Lazarus, which is why I went to all this trouble. They’ve now sold half a million of these things. At least a few of those people ought to be willing to buy a Lazarus tutorial for it. We’ll see.

CS2 Flies In From Adobe’s Left Field

Colds are like…well, you know what colds are like. Right now, everybody has one. I’ve been climbing out of this one now for about six days, and the top is not yet in sight. At least my flu shot worked, or I could have been in lots worse shape. If I’ve been quiet, that’s most of it.

But something remarkable happened yesterday that still has a lot of people scratching their heads. Michael Covington and several other people alerted me to the fact that Adobe had opened a download link to an installable instance of Creative Suite 2 that didn’t require activation. Rumors were thronging like Illinois mosquitoes that Adobe was just turning it loose. This is outside of type for them, let’s say.

The truth is subtler: Adobe is shutting off CS2’s activation servers, and once it does, people who have legitimate licenses to CS2 will not be able to reinstall it after a hard disk crash or whatever. So they’re providing an activation-free instance to those customers.

Why, then, did they put the download links to the installer files right out where anyone could see them? The links have been live for several days and were still live this morning, though the server has been choked here and there by activity that suggests more than just CS2 atavists clicking on the links. One would expect at very least a requirement for users to log into their Adobe accounts to get the install suite, but not so. Any code monkey could suggest four or five other ways to do it that would not present all of CS2 on a platter to the whole world.

Adobe insists that they’re not giving CS2 to everybody. So what’s really going on here? I’ll hazard a guess: They’re afraid of the Gimp, and to a lesser extent, Scribus. I think they’ve been afraid of both programs (and a scattering of others) for a long time. At some point, a bean counter probably did some spreadsheeting and realized that activation support on a long-tail product isn’t worth what it costs, and told the techies to shut it off and send the phone reps home.

Faced with that decision, somebody there may have gotten clever enough to realize that people were leaving the CS plantation for cheaper realms. The Gimp is good enough for most Photoshoppish work, according to people I respect, and if I didn’t already own InDesign 2.0, I’d probably be laying out books in Scribus. I think Adobe may be quietly trying to get more people hooked on the CS product, which is a huge revenue-generator for them. Photoshop is probably the most pirated non-OS in software history, and I wonder if they’re just making CS2 easier to pirate and looking the other way to pull a little pressure off CS6, while allowing the curious to give Creative Suite a go. There are legal reasons why they won’t admit to a strategy like that. Furthermore, as many have said, never attribute to cleverness what is better explained by incompetence. It may just be a booboo. If it is, it’s one of the longest-lived booboos of its sort I’ve ever seen.

I won’t post the link here, out of respect for Adobe’s copyrights. Trust me, you won’t have to flatten your nose to find it. I have only one more point to make: I’d like to buy that software. Yes indeed: Adobe, I’ll give you money! I won’t pay several grand for CS6. But I’ll pay a couple hundred for CS2. Alas, the product is not for sale. So what could be a revenue generator for Adobe is just another gift to the pirates, with people like me who’d like to remain legal looking on enviously.

I respect their copyrights. But still. Dumbasses!

Odd Lots