Monday 21 January 2013

Substantial progress today

Yesterday, it was two steps forward, two steps back. But today was good.

I set up two Pies as servers, only to find that the Pies were too slow to handle what they needed to do. I think it was the CPU speed that was the problem.

So then I tried to change the "Dr Solomon's Railway" to run on a Pi. That worked OK, until I ran into a problem I've had before. The relays that switch things on and off, are controlled via a serial link. The Pi doesn't have a serial port, so I tried to use a USB-to-serial converter. I have two different types of them, and both of them tend to crash the Pi when used. I tried to get RS 232 from the GPIO pins, amd I sort-of half got it (I was able to see things that I typed on the Pi, come up on another computer) but I couldn't control the relay box that way. After wasting several hours trying to make something work, I gave up, and the serial link is now being controlled by a tower computer, which kind of misses the whole point of moving to a PI.

I haven't given up, though. I looked at the list of "What works with a Pi" and I've ordered a couple more USB-to-serial links, and also a relay box that can be controlled via USB. Surely one of those will work!

Today, I had a lot more success. First, a heavy parcel arrived - it was the four batteries I ordered to re-battery a UPS. That was a fairly easy task, and now I have a good-as-new 2200VA UPS that (unlike the APC Smart-UPSes that I have) aren't too heavy to lift.

Next, I set up Ann's Pi. Ann is a total Luddite, and all she does is use it like a typewriter.  There were two challenges here - first, (unlike all the servers) she needs a monitor. I didn't want to fork out £100 for a new HDMI-capable monitor, so I got a £10 HDMI-VGA converter. At first, I couldn't make it work, but I did a bit of Googling, and changed the config.txt on the Pi to read hdmi_safe=1. That worked! Then it just took a bit of experimentation to see what was the best mode and what overscan was needed.

The second big challenge, was to make it work with the printer, a Brother laser printer. First, I installed CUPS. Then I discovered that, although CUPS knows about a hundred or more Brother printers, it didn't know about this one. I found a driver for it, but I couldn't install it because the driver expected to run on i386, and the Pi is ARM. Eventually, I gave up looking for a driver, and lied to CUPS about what sort of printer it was, and that got it working. The key was to tell it that it was an HP Laserjet clone.

And then I discovered that the Pi doesn't come with a word processor. After a bit of research, I installed focuswriter and abiword. Abiword is very sluggish, so I decided on focuswriter, although it has a very unusual habit of not showing you its button bar and menus unless you mouse to the top of the page, and then they suddenly appear. And I couldn't see a way to tell it to leave them there permanently. Never mind - it looks like a typewriter, so I think she'll be happy.

Since I now know that the VGI-HDMI adaptor works, I ordered three more; about £6 each. I also got three more of the little voltage step-down boards, and half a dozen more of the £2 USB hubs that I'm using as USB hubs and for powering Pies.

Yesterday, I ordered six more Pies from RS-online. Today, I got an email saying that they've been shipped! I wasn't expecting that - previously, there's been a delay of a few weeks, which is why I ordered them now even though I don't need them yet. I guess they've sorted out the production. Or possibly when RS say "shipped" they mean "not shipped yet". I think they're telling the truth, though, they gave me a Parcelforce tracking number. I'll find out tomorrow.


  1. So, Doc, is the rumour true, that you.. THE Dr. Solly, are planning to rule the whole of the internet and non computer linked world with an army of Pi's?

    ps What IS the plural of Pi? (ha ha, no its not 3.1415926 x n!)

    1. All the rumours are untrue.

      It's "Pies". Or at least, that's what I decided I'd use. "Pis" looks wrong, and "Pi's" is even worse.

    2. ok, thanks point taken, I bow to your better judgement of English Grammar!

  2. How about a piface it has two relays on it which could run the railway????

  3. Http:// ;) that's how I got one

  4. Two relays for £30. I prefer the "eight relays for £20" deal :-)