Friday 30 November 2012

Alconbury again

It was very cold today; the frost on the car was thick, and so I wore a t-shirt, three sweaters and my coat. That turned out to be enough; the only part of me that got cold was my fingers when I had to take my cloves off to sign logs. Oh, and two pair of trousers, and two pair of socks. There's no such thing as "too cold", at least, not in England, there's only "not enough clothing".

North to Alconbury. First the new Coppingford circuit by Poshrule; entirely on bridleways, byways and roads, so I went round on the bike. And then Alconbury Amble - I've already done most of these, so I was just going to get some more.

Part-way round, I met Sscafe walking the other way round, the UK's number two cacher (and at the rate she's going, soon to be number one). At first, neither of us recognised the other - that was partly because we were both bundled up against the cold, and partly because I was biking along the bridleway, she was walking across the field, so she was a few dozen yards away. but when I got to the next cache, I saw that she'd signed the log today (and she saw the same at her next cache), so I phoned her, and we agreed to meet up after we'd both done our circuits.

So we sat in the relative warmth of my car and talked caching, and batteries, and more caching, and we did a couple of caches together, and then went our separate ways. I wanted to finish off "A dozen Dashes".

So I drove around for a bit, and picked up more of that series, and although there was one I couldn't find, I decided I had enough to go for the final.

My first attempt was clearly to completely the wrong place. But then I tried again, and this time I went along an excellent track, and when I got to the place I'd marked, there was a one-plank footbridge (and the hint was "troll"). But although I looked under the bridge really hard, I couldn't see anything. So I gave up and went home.

A good day out, although cold. And the Raspberry Pies had arrived in the morning, so I had that to look forward to.

Nine Pies

This morning, as I was about to leave for a day's caching, a Parcelforce van pulled up, and I was asked to sign for a parcel. On the outside of the parcel, it said "RS". That's Radiospares, or at least that what they used to be called, I think they call themselves RS Components these days.

Anyway, there's only one thing I've ordered from them recently - ten Raspberry Pies! So I signed, took them indoors, and then went out caching.

When I got back, I opened the envelope (they were each in a nice plastic case, and the whole lot in a flimsy Tyvek envelope, lined with bubblewrap. And I counted them. Nine. Oh. The delivery note inside said ten.

I think I know what happened. here's a picture of the package.

The blue splodge is me not wanting to put my address on the internet.

As you can see, it's been opened, and then closed again with a couple of strips of sticky tape. Either this happened by accident, and Parcelforce resealed it (but surely they'd have done it rather better?) Or else someone opened it on purpose and stole one of the Pies.

I'll call RS as soon as possible to tell them about this, and ask what they plan to do (although, since I signed for it, the answer is probably "nothing"). Should I have opened the package and counted the contents, given the state it was in? Probably. But I doubt if I would have, and anyhow, I'm usually not there and someone else would sign for things, and they certainly wouldn't have counted them.

Oh well. It's not that big a deal. One Pi is £20-worth, and it's not like I bought ten because that's exactly how many I needed, it was just a round number.

What is excellent, is that the delivery date was supposed to be December 18, so they're a couple of weeks early, and I was expecting them to be somewhat late, because things often are.

Of course, all the bits and bobs (SD cards, cables etc) aren't here yet - I wasn't in a hurry to get those because I wasn't expecting the Pies just yet. But I'll be able to get at least a few of them into action.

Thursday 29 November 2012

Rebooting the pi

Hmm. Is this pi stable? It's crashed a couple of times, which I don't like, I'm used to computers that keep running for years at a time.

So I've done the following.

1. I have three webcams and the Maestro servo controller all taking power from the pi. I've changed that so they connect to a powered hub, lessening the load on the pi.

2. I've made a power cycler for it. My first thought was to run the pi off the USB of another computer, and tell the other computer to cut and restore power. But it turns out that USB ports can tell devices to power off, but they can't actually cut the power. So instead, I'm using a relay, controlled by another computer (actually, I'm using the same relay box that controls the power to the lights and the servos), and I've made a little web interface for it, so from anywhere in the world I can reboot the pi. No, I'm not telling you the URL. And that works great.

3. All the things that need to start up when the pi starts, I've made happen automatically. You do that by putting commands in /etc/rc/local

I've also been having other hardware problems. A computer I use purely for multiple terminals, was singing. Actually, it was a two tone sound like emergency sirens use, only quieter. But still annoying. So I powered it off, and had a look. It turned out, there's three fans inside. The CPU fan had stuck, one case fan had stuck, and the third case fan was running, but very noisy. So I replaced all three fans.

On another computer,  the hard drive was getting a rapidly increasing number of bad sectors, so that's been swapped out. And on a third, the hard drive dropped out, so that got swapped too. What those two have in commopn, is that they're both certified Seagate repaired drives, sent to me in replacement for drives that had failed.

More bike maintenance. Battery 8 wouldn't fit on the carrier. I phoned Alien, and they suggested filing it down. So I did that; it's in a plastic molded case, and there's line standing out where the mold was. So I've filed it all flat, and sanded it, and not it fits on, albeit with quite a lot of force.

While I had the bike out, I had a look at the back brake, which had suddenly become almost useless. The cable had loosened, but when I tried to tighten it, I found that the frayed end had slipped through the holding nut, and I didn't fancy coaxing it back. So I replaced the whole brake cable, which turned out to be pretty easy to do. I put a few drops of oil inside the cable outer first, on general principles, and then the inner just slid in easily. I also adjusted the saddlebags so they fit slightly better. I'm taking the bike out again tomorrow, to Huntingdonshire.


I accidentally deleted the robot arm software on the pi. It's an easy accident to have; I typed


which will display the software on the screen.

But I'd already typed rm on the line, so the line was

rm cat

which tried to delete cat (which wasn't there), then did delete


Some days ago, when I started doing more than just a bit of tinkering on the pi, I set up a backup system. Each day, all the files on the pi are copied to another computer. So all I had to do was go to that computer and copy the file back to the pi.


A lot of people don't have backups. Or they think they do, but have no idea whatsoever how they might get back a file they've accidentally deleted.

Are you one of those people?

Wednesday 28 November 2012

The Woolley Mammoth

I noticed this one - 60 caches in ten miles, and decided to have a go.

I parked near number 48 - my plan was to do the lower section (in reverse order) because that looked mostly bikeable, and I'd be able to zoom back to the car after doing about three dozen caches; I'd also have the option of leaving the bike and doing the rest on foot, then driving to pick up the bike. So I set off.

The caches were all pretty easy, although some of them have become very wet. And the track to the second and third was over loose soil, which is the worst - the bike gets clogged up and I can't even wheel it. But I managed to get across, and then I was on bridleway, on grass. The ground was very wet and soggy, but bikeable. And after that, the terrain stayed good for almost the whole trip. And I didn't have to do any heavy lifting.

I got to Spaldwich at about 2pm; that was the point at which I had a decision to make about how to proceed. I decided to continue on the bike, which turned out to be a good choice. There was one more loose-earch stretch, but I'd picked up a useful stick to unclog with, and I promised the bike a thorough wash-down with the pressure washer (now that the terrible drought has ended etc etc) when we got home. The bike did its part well; I got through 2 1/2 batteries (I'd taken three with me, on the grounds that I'd probably need them). I did the last dozen or so in the gathering dark (using my head torch), and it was full dark by the time I got back to the car, at about 5pm. So the route, advertised as five hours, took me seven - I'm pretty slow at caching. I find that going slower means I fall over less. But it did mean a very late lunch.

And I'm very glad I didn't use that big main road on the bike - it's the A14(T) and the traffic is fierce, and there's no bike lane.

Round about number 55, I started hearing a high pitched beep, coming from the front. At first I thought, is this an error message from the bike motor I didn't know about? Or is it my phone doing something it hasn't done before. Then I came up to the source of the sound.

The vertical line you can see towards the left is an antenna. The grey thing in the foreground was what was doing the beeping. The notice says "Danger high noise levels", so I guess when it gets angry it does a bit more than the pathetic little beeps I was hearing.

A total of 67 caches today, and because I was mostly on the bike, I'm not excessively exhausted. An excellent day out.

Weight report 28

15 stone, 9 pounds

Monday 26 November 2012

Working on the robot arm

I decided to add another webcam, this one giving the view from above. So I've put a webcam upside down, sellotaped to the underside of the shelf above the arm. This, of course, means that the picture is upside down. No problem.

apt-get install imagemagick

That gives you a command line group of programs to do any image manipulation I can think it; inverting an image is easy. But it only partially installed. never mind; apt-get update, followed by apt-get install imagemagick did it. and then the image inversion is done by

mogrify  -rotate 180  -format jpg -quality 80 temp3.jpeg

And then some small mods to the page that displays the pictures, so I can get all three on.

I also noticed that the Creative cams were a *lot* more stable than the W300A cams. The images are captures better, and the images don't break up. I don't know if it's the cam itself, or the software, but I kind of don't care. I replaced the W300s with Creatives (I had a few in a box, left over from another project).

It really is good having loads of bits and bobs lying around!

I also did a bit of research following something I was talking about at the Raspberry Jam. I had a look, and it is possible to turn a Pi into a wifi hotspot. I've ordered a couple of insanely cheap wifi USB dongles, and when the rest of the pies arrive, I'll try that. Under £5 each, including postage. Cheap as chips.

But, some bad news. When I tried changing the power cable for the stepper motors to something that I thought wuold be more stable, there was blue smoke coming out of the motor that rotates the whole arm. And, sure enough ... it's blown. Bah. I'll have to replace it.

   ..... later ...

OK, I replaced it. But the replacement suffered from severe judder, so I replaced that, and now it all seems to be OK. I've ordered three more stepper motors; I'm guessing that I might have to do more replacing in future. So this time, I've got servos that are more powerful and durable, I hope.

The Pi seems to be happy with all this. It's now running three webcams and the Maestro servo controller off its USB, using an unpowered hub, so all four devices are taking their power from the Pi, without (I think) problems.

Sunday 25 November 2012

Raspberry pi jam, and a day out caching

I attended the fourth meeting of the Milton Keynes Raspberry Jam, held in Bletchley Park. It was a good meeting to go to; I had a look at projects that other people were doing, helped out slightly with a bit of linux knowledge, got a few free stepper motors and batteries, gave out a couple of free hard drives, found someone who could supply pies at the drop of a hat, with a very slim markup on the usual price (as well as lots of other very interesting bits and pieces,, told people about my own pi project, the Geocaching Robotic Arm and hooked up with smstext for the afternoons caching.

After the meeting, I toddled along to the National Museum of Computing to see the Witch, the oldest working digital computer in the world. It uses a mixture of decatrons and relays, and can multiply two numbers in only 17 seconds.

It makes a lovely whirring and clicking noise as it operates. It's wonderful that this grand old lady has been brought back into use.

Then we saw several other computers, including the Elliot 803 and 905 that I used 42 years ago, and finally on to Colossus.

Colossus wasn't what I'd call a computer, it didn't have the ability to change execution on conditions. But it's certainly a very significant ancestor of the digital electronic computer, and it's great that they've resurrected one.

Then on to caching. Since I'd hooked up with smstext, I thought we could do the MKBW Grey series, by leaving a car at each end, then walking the route. That worked well, and I was very glad I hadn't gone by bike, because at one point we had to go through water six inches deep, and at another point we had to improvise a bridge using a plank, over water that was at least 18 inches deep.

After walking that route, we then went on to do Norfolk12's new night cache, and finished with the MKBW Golden Bonus.

An excellent day out!

Saturday 24 November 2012

The return of the Geocaching Robot Arm!

I had a five-degrees-of-freedom robotic arm; you could control it over the internet, and see what you were doing via a webcam.

But the tiny PCB that interfaced it to the PC stopped working, and I couldn't find a replacement. So I archived the cache. But now!

I've found a different PCB to control it, the Pololu Micro Maestro, which I got from Hobbytronics for £15.76. It's a tiny little thing, an inch or so, but it's very nice. It will take USB (and is powered from the USB), but I can use a separate power supply for the stepper motors that power the arm.

I connected it to my desktop computer, and then started installing stuff; I think I installed .NET. I'm not sure because modern practice is to hide all the technical stuff behind a barrage of marketing-speak. I connected the Maestro to a stepper motor. I installed a USB library. And then I messed about with it a bit until suddenly, the stepper motor buzzed; it was working!

So, I powered up the computer that used to control the arm. It was a *very* old version of Linux (Red Hat 8); several years old, and it didn't use Yum. Yum is that way you install Fedora Linux software; you type "yum install whatever", and it goes and gets it and installs it for you. Payment? This is open Source; you don't pay for it, it's free.

After a while spent installing software the way we used to way back then (10 years ago), I decided, blow this for a game of soldiers, and brought another computer out, this one running Fedora 6, vintage 2006. This had yum, and was looking OK, but I couldn't make the web cam work, and some of what I wanted to use wasn't yum-installable. Then, in a flash of inspiration, I thought "Raspberry". So I powered up the Raspberry Pi. That uses apt-get to get software (this is Debian Linux) which is really just yum but a bit different. And that turned out to work like a charm. I just apt-getted (apt-got?) a few things, and the webcam worked, the Pololu Maestro worked, and the external relay box worked. And at that point, ladysolly stuck her head in and said "I hope you're not going to be running a load of noisy computers all night?" No, I'm not; the Raspberry has no fan, and it's totally silent.

You can see my thumb; that shows you how tiny the Pi is.

So, here's the way it works. The Raspberry is at the core of it all, and I'm using a USB hub to plug in two webcams and the Maestro. The Raspberry sends commands to the Maestro like "UscCmd --servo 1,6000" which tells the Maestro to move servo 1 to position 6000, and the Maestro controls the six servos that power the arm. The electrical power for the arm comes from an old PC power supply; that gives me a very steady and reliable five volts which is what the servos want.

There's two webcams, because with only one, you only get one point of view, and you're trying to position the arm in three dimensions. The second webcam helps a lot. The webcams are different; one is a very, very old cam I've been using for this sort of thing for maybe 10 years, it's a Creative webcam. The other is a Mustek Wcam 300A, a mere 7 years old, and was part of a project I did back then. You can see that the colour balances are quite different; the smaller cam is closer to reality. The interesting thing about this, though, was that both of them worked straight away, as soon as I connected them to the cam and ran the software (called 'streamer', a very simple program, which seems to work where others make me struggle to get them going).

In this picture, you can see the Maestro. It's the tiny PCB with the green and yellow LEDs.

And there's a relay box, so that the power to the arm, and the lighting, can be switched off when the arm isn't being used. I'd run that off the Raspberry too, but when I try, the power draw is to great that it crashes the Raspberry. So I've got that controlled by a different computer, and the Raspberry sends it a message when it wants to turn off the power. I've ordered a powered hub, though, and I'm hoping that if I use that, I'll be able to run the relay box off the Pi.

Still to do. I have to create a puzzle that needs to be solved in order to get access to the robot arm; that's necessary because if multiple people use it at the same time, they'll trip over each other's feet. So I need a way to thin out the access a bit. And I need to hide a cache that this will give you the coordinates for.

So, until I get the cache in place and the puzzle ready, you can play with the Geocaching Robotic Arm

Let me know if there's any problems.

Friday 23 November 2012

Water, water, everywhere

Up to Milton Keynes again - if I can get the Green bonus, then I'll have all I need for the Golden Bonus. I already have some of the Greens, so there's another 16 I can get.

First, get the bike together, and that's when I discover that my new battery, B8, can't interface with the bike. I had a similar problem with B7, I have to push it *really* hard to get it in place. With B8, it just won't go. I might have to file something down a bit.

So, on the road ... or rather, on the bridleway. The next thing I discovered is that all the rain in the last few days has made the ground really, really soft, and so biking is difficult. I started at Green 10, and worked my way along. I did Green 3, and then looked over the style. And this is what I saw.

The track goes along the hedge, straight through the flood. I decided that there was no way of knowing how deep it would get. This is the first time I've actually turned back and abandoned a planned route. I also decided that there was no way around it. And furthermore, I also felt that it would be pointless to try to approach these caches from the other end.

So, back to the car to complete what I could of the series. I also had one DNF, so that's three of the Greens not done. But I got the bonus, that's the main thing.

Where did this flood come from? It's the river Tove, which is a triburary of the Ouse. Here's what the Ouse looks like:

And to give you some idea of the depth:

That's a dog poo bin; I'm guessing that it's on the footpath along the river. It's up to its chin in water.

And here's the view on the other side:

Water as far as you can see.

So I gave up after I'd done the Greens, and went shopping in MK at Evans Cycles for knee protectors.

Wednesday 21 November 2012

Rain rain rain

I had hoped to go out today to finish the Green section of the MKBW, get the Green Bonus, and therefore the info for the Golden bonus. But the forecast was for heavy rain, and I sit here now watching the heavy rain falling, and being glad that I'm not out in it. But the sunset is in a clear sky, so I'm optimistic about tomorrow.

The bad weather means I've had a chance to think more about Raspberry Pies.

I've ordered a couple of dual-drive Sata USB docks. It occured to me that I could probably use two of them with a Pi, to get a four-drive computer; since drives are 3TB these days, that's 12TB. The power draw will be pretty low, I think. Experiments will tell me if this is practical.

I calculated my cost of electricity - it's horrendous! I'm paying something like £6000 per year to power all these computers, including the air conditioning which is needed (I know it's needed, because I left it off overnight, and the temperature climbed to 34 degrees C). So it's well worth looking at how I can get that down.

I've got 45 computers running here, each drawing about 1/2 amp at 240 volts = 120 watts. My Really Big servers, with up to 16 drives, take more like 300 watts. A Pi draws 2.5 watts. A hard drive draws about 8 watts, so a Pi plus three drives (which is about my average) would be 26 watts. But the power supply chews up some power itself, my tests indicated about 10-50 watts (quite a range). But one PC power supply can drive a lot of pies.

I looked at a 500 watt power supply. That draws 16 watts for itself and its fans. And it will supply 33 amps at 5 volts, enough for 66 pies. And 18 amps at 12 volts, enough for 27 hard drives. A 550 watt power supply takes 22 watts for itself and its fans, and supplies 45 amps at 5 volts (90 pies) and 25 amps at 12 volts (37 hard drives). Which means that I can ignore the amount that the power supply draws for itself, because it averages out at a fraction of a watt per device it's powering. And it means that another good idea will be to use two power supplies in parallel to power a batch of pies and drives; that way, if one of them fails, the systems keep running, and I can change the failing power supply without switching everything off.

So it sounds like I could cut electricity consumption by up to 75%. Maybe.

One of the things I've been doing, is combining functions. It's a rule I've often heard, one role per computer. But then you wind up running a lot of computers, all slurping down the electricity. I've eliminated three computers completely, by giving their functions to other computers that weren't doing a lot, and I'll be looking for more savings in this way, even before the pies arrive.

I've also been looking into how to back up the pies. I've done a full file-by-file backup of the SD card as it was yesterday, and I've done an image of the card (I can use that to do a very quick install of the other Pies, when they arrive). but for routine use, I want something that happens automatically.

So I've written a program that accesses the root directory of the card across the network, and backs up each directory tree from the root, looking for files that have changed (excluding /dev and .proc, of course). I'm using the program, available here - I've been using it for 15 years, and it's great. I keep three generations of backup, one that's taken on the 1st to 10th of the month, one taken on the 11th to 20th, and the third on the remaining days. That way, if something dreadful happens and the backup is corrupted, if I find out within a month, I can go back to a good copy.

Also, I had a chat with Jason - he's buying a Maplin's robot arm for his boy. That made me think of the Geocaching Robot Arm, which was very popular until the controller board died, and I couldn't find a replacement.

I had already looked into the Maplin thing, and I decided that it wouldn't be what I wanted, as it uses ordinary electric motors, not stepper motors. You can't control the arm as accurately as you can with stepper motors, and since people will be using this across the internet, with a long lag between them giving a command and seeing the result, I do need accuracy.

But it got me thinking again, and I had another look for the controller board - I still couldn't find one the same. But I did find something similar - the Pololu six-channel Micro Maestro USB servo controller,
which can control up to six channels (I need five) via USB, and it's not expensive, so I've ordered one. The Geocaching Robot Arm might get to live again!

Women can't be bishops

The Church of England has decided that they definitely aren't going to allow women to be bishops. I have a few questions.

1. Why do they have this exemption from the law that the rest of us have to follow?
2. And, by the way, why are they allowed to make advertising claims that cannot be substantiated?
3. Why are there a bunch of bishops in the House of Lords, affecting the legislation that I have to follow?
4. I get it that some of them believe that the bible justifies their position. But people used to believe that the bible also justifies slavery, although I doubt if many people still believe this.
5. You can find support for pretty much anything in the bible; you can/can/t eat pork, you a can/can't go to war, you make Saturday/Sunday a day of rest. To decide what is right and what is wrong, you have to appeal to a higher authority than the bible - your own conscience.
6. How come they accept a woman, Elizabeth II, as the overall head of the Church?

It might be argued that, as an atheist, who has never knowingly attended a CofE church, I'm not entitled to have a view on this. But I don't have to be a thief to know that it's wrong.

On the other hand, since this position is likely to accelerate the decline of the church, which many people think is a Good Thing, maybe the synod was guided to this position by the Hand of God.

Weight report 27

15 stone 13 3/4

Tuesday 20 November 2012

Blown away even more

One of the things I thought I might do, is attach a webcam to a Pi, so I can see what's going on outside ... even when I'm not home. For that to work, I need to attach a USB webcam to one of the Pi's usb ports, and get some software that will take snapshots.

I already have a suitable cam, and in the past, I've used "motion" for this task. But that was on Fedora linux, on an Intel chip. Still, it's worth a try.

"apt-get install motion", and a quick edit of the paramters, and a quick adjustment of the webcam's focus, and voila - it worked! A couple of minutes after starting this project, I was seeing pictures of outside the house.

So far, I haven't thought of anything that I'm already doing on a Fedora Intel box, that I can't do on a Pi.

I've now set up a backup system, that will back up the Pi to my backup system, automatically, each day.

A dish of Pies

I've set up a prototype; it uses a 1U power supply (suitably modded so that it runs even though it isn't powering a motherboard), a couple of 12v fans, a 12v ethernet switch and a 12v relay for cycling power to 8 things. I had to make adapters from the 1U power supply to power the ethernet switch and relay; they expect to be powered by wall-warts, but they seem happy enough to get their 12 volts from the 1U power supply. Then I measured the power draw.

The PSU, without doing anything, takes 88 ma. I hadn't expected that - it puts a floor under the whole thing. The ethernet switch takes 30 ma, the fans take about 10 ma each, and the relay box about 1ma. Pies will pull 500 ma at 5v, which is 10 ma at 240. So a dish with 8 Pies will draw 230 ma, and a dish with 16 will draw 310 ma. This should be compared with a conventional server with 6 hard drives, pulling 440 ma. The dish will still need at least one conventional server, because I can't see how to attach hard drives to a Pi (I know I could use the USB port, but I have a feeling that this will put too much burden on the Pi's USB system).

Checking the power supply, it says that it can do 12 amps at 5v, and another 10 amps at 12v, so the power supply will be very lightly loaded by 16 Pies. It's a switching PSU, of course, so it should give *very* stable power.

Just one fly in the ointment - I only have one Pi. The other ten are supposed to arrived December 18, although I'm not optimistic about that.

Monday 19 November 2012

Shin guards

I saw a girl today wearing shin guards, and I thought, what a good idea. Shin and knee guards. So I had a look, and bike shops sell *loads* of them. I don't think I'll buy online, though - I want to try them on and see if they fit. I also want something that wraps around my knee, protecting the sides from impact, becasue that's where I get hurt in mounting or dismounting the bike.

Thoughts about the pi

My colo just put the price of power up, from £17 per amp per month, to £30. I use 4 amps, so that's an increase from £68 to £120.

At a colocation, you pay for three resources - space, amps and bandwidth.  The bandwidth is usually 100 mbit, but how much you need, depends on how much you need, if you see what I mean. It's hard to make economies. But space and power ... you can. 1U cases are 1.75 inches high, that's the standard for 19 inch racks.

When I got home from my bike ride, I put a powermeter on a few servers. My conventional 1U servers pull 500 milliamps (half an amp) at 240 volts. But the pi pulls 500 milliamps at 5 volts, so when I put the power meter on the transformer that supplies it, I wasn't at all surprised to see that it pulls 10 milliamps at 240 volts (which it converts to 500 milliamps at 5 volts).

So here's what I'm thinking. Take a 1U case, and a 1U power supply. Line the case with tape, to guard against pies getting short circuits if they touch the case. Attach the pies using tiny magnets. Bodge the power supply so that it will power on even though it can't see a motherboard (that's an easy fix, you connect one wire to short a couple of the pins on the output). Use the 5 volt output to drive, say, eight pies. Run the power via a relay board that allows me to switch on or off any of the eight pies (being able to remotely cycle the power is very useful), and that board runs off 12 volts, also available from the power supply. Put in an 8-way ethernet switch, also powered by 12 volts. Put in a few fans to keep the air moving inside, also running off 12 volts. The total power draw, with all pies on, will be 80 milliamps for the pies, and a bit more for the ethernet switch and fans. One ethernet lead comes out of the box, and one power cable. So that'll probably be about a tenth of an amp or so for the whole thing.

Actually, I can get at least 16 pies in one 1U case. Pulling a fifth of an amp. Compare with a normal 1U server pulling half an amp.

Well, it's not quite as simple as that - you can't connect hard drives to the pies. So what I'd do, is have six 3TB hard drives in a 1U case (which would be about 0.5 amps), then six more in another (as backup), and six more in a third, but powered off, so not costing any power draw. And the pies would access them across the network, using nfs or Samba. Which means I wind up using about 1.2 amps instead of four. And the space taken up is less also.

So, first thing is, to make one of these things and see if there's any practical problems. Second thing is to find a name for it. What would you call a box containing all the above?

Sunday 18 November 2012

Milton Keynes, Indigo and Grey

I've already done six of the Indigo series, so my first mission today was to do the others. I parked in the village near the end of the series, and mounted up; I took only one battery,becasue this was a fairly short run. I found them all, including the bonus, and picked up a Dragontree cache on the road trip back. But halfway back, I ran out of battery. Fortunately, and electric bike with an exhausted battery is still a bike, so I pedalled back to the car. Normally, I have assistance from a 250 watt motor, that's about 1/3 of a horsepower. I add about 150 to that, so between us, we're half a horse.

Back in the car, I had my lunch, and got ready for the next ride - the Grey series. This is a very long series, but I wasn't planning to do the whole thing, maybe half of it. Actually, I did 23, which is indeed about half.

But that route was a lot harder. I started off with a few lifts over stiles. After that, it was all bridleway, but part of the route was across a freshly ploughed field (I went around it) and another part was across a ploughed and harrowed field - I couldn't see a way to avoid going across that. Then I did six more caches than I should have, and ran out of battery on the way back (which means I'd exhausted all three batteries). So I've just ordered a fourth one!

I got back to the car at 7pm, just in time to get back home at the correct time for dinner. But it was a close shave - I couldn't ride the bike up a hill in the dark on soft ground, so I had to push it. And I got myself on the wrong side of a hedge on the way back, and had to backtrack.

49 caches done today, and I'm well tired.

Along the way, I was thinking about raspberry pies and how I can deploy them - I'll make that a separate post.

Friday 16 November 2012

Milton Keynes, red series

Up north again, for a long bike ride. I started in the middle, and went East then back via the road. And then I went West, and back on the road. And then North, and then home.

On my West trip, I ran into a building site - a big one. And I was just about to go along the public footpath, when a man in a yellow hi-vis jacket who was sitting on a chair on a footbridge, said that I couldn't; they were bulldozing and it was too dangerous.

This put a complete kibosh on my plans, because there wasn't any way to get around this. but just as I was trundling the bike dejectedly away and starting to rethink my plans, another man came along and told Mr Hi-vis that actually, the reason he was sitting there wasn't to turn people away, it was to conduct them safely through the site. So Mr Hi-vis and I were soon trundling my bike just where I wanted to go. Along the way, I explained about geocaching to him, so that when I stopped, in the middle of the site where the bulldozing was most energetic, he wasn't surprised, and he held my bike while I found the cache.

So I left the building site behind, but then I encountered the dreaded claggy mud, which jams up into the bike wheels and makes it impossible to trundle. I had to clear out the mud a few times before I left the area.

So I got back knackered, and I won't be going out tomorrow!

Still, I got the bonus, which will go towards the Golden Bonus, and I got one of the GCSE series, and altogether, despite the mud and a little rain, I had a good time.

Wednesday 14 November 2012

Weight report 26

16 stone 3 1/2.

That's the Birthday Effect. I ate too much!

Nameserver on Pi

I've set up a name server on the Pi. It was pretty easy; I mostly copied the files from my existing nameserver. Dig and nslookup weren't there; you have to do apt-get install dnsutils to get them. No problem.

I also want to install pine. I'm sure mutt is a good mail-reader, but I'm very used to pine. Here's how to install it:

I tried it ... but it didn't work.

Tuesday 13 November 2012

Still blown away

It turned out that the Pi crashed because the SD card stopped working, so not the Pi's fault. So I'm still blown away.

I've listed ten of my servers that can be replaced by Raspberries.

I've decided to go with Raspbian. So I set that up on an 8gb card, and downloaded and installed: sendmail, bind9, rdate, mutt and courier-imap. Those will give me respectively: email sending/receiving, DNS, date/time setting, email reading and imap (letting other servers pick up email).  When I shut down the GUI on the pi, and load all those on it, it uses 128mb, leaving 360mb free memory, which is a lot. It isn't using the swap, which is good.

I've ordered 10 more pis. Pice? To power them, I've ordered five powered USB hubs, at £2 each, and I'll put my own power supplies on them; I'm thinking of using more powerful supplies than the usual mingy 500 ma supplies they offer. I had a look at a standard PC power supply, and it'll give me 20,000 ma at 5.25 volts, perfect. Pice want 700 ma each.

From the hubs, will come USB-to-micro-USB cables, costing about 50p each. And I've ordered 10 8gb Sandisk Ultra SDHC cards, costing about £6 each. This should all arrive in a few weeks time; the pice are predicted for December 18 (they're on back order at RS), so maybe I'll see them early in 2013.

Monday 12 November 2012

Ingatestone circle

Out for my birthday with ladysolly to Ingatestone. 20 caches done, and a very nice day out.

Along the way, this sight greeted us.

It's an artistic triumph - the red of the cushion contrasts nicely with the green of the grass, the natural-effect plastic trim goes well in this rural setting, and the while laminated highlight boards make excellent use of the natural lighting. I hope the council, in their ignorance, don't just ship the lot to the nearest dump.

A bit less blown away

I left the Raspberry Pi on overnight. When I looked in the morning, it was still running, but there were several copies of CROND running (which indicates a problem), and I couldn't tell it to reboot. So I switched off the power, and on again.

The red LED came on, indicating that there's power, but the pi didn't start up.

I'm not as impressed as I was.

Sunday 11 November 2012

Blown away by the Raspberry Pi

I am absolutely gobsmacked. It's terrific!

We got home from caching today, and I decided, time to try the Pi. I plugged in the power, an ethernet cable, an SD card, and I was immediately able to ping it (I'd set up a static IP address when I was setting up the card).

I tried Raspian, it worked immediately. I tried Fedora, it worked immediately. I plugged in the HDMI to my monitor, switched my monitor from analog (VGA) to digital, and got a display. I plugged in a USB keyboard, it worked. A USB mouse, it worked. I'm writing this blog on the Pi, which I've thoughtfully named pi001, because I'm thinking of buying half a dozen more.

The graphics are glorious; it's running at 1890 by 1170 pixels (which is almost the same as the 1920 by 1200 that the screen is capable of).  The speed at which things happen is amazing - it's not as fast as one of my ordinary PCs, but when I grab a window and move it around the screen, there's almost zero refresh lag. It doesn't crash; actually all I can say is that it hasn't crashed in the three hours I've been using it.

I'm writing this blog entry on the Raspberry.

Now remember this. It cost £20, and you can add maybe £3 for the SD card (although actually I'm using one that I had in my drawer and have never really used for anything).

I'm blown away. This isn't £20 worth of computer, it's £200.

There seems to be a bit more software that comes in the Fedora distribution than in the Rasbian, but neither of them come with a DNS server or a mail server; I'll have to look around, but I'd guess that the venerable Bind and Sendmail have probably been made available for ARM cpus. I've already read somewhere that I can run Apache, and I think I can get Perl for the pi. It seems to be only using 180mb of memory out of its 512mb, I'll have to look into that.

There's a header block called GPIO, you can control the pin inputs and outputs, I'll have to look into what I can do with that. I can also try putting a USB-serial converter on it, and from the serial port, I can control an 8-port relay block that I have; I wonder if I could rescuscitate the Geocaching Robot Arm with this (the controller board, a Basic Stamp, died and I couldn't find a replacement).

We're visiting daughter.1 tomorrow; I have a laptop there, and I'll be able to log into the pi remotely from there (because ssh works) and play with it some more.

It is a fully-fledged computer. For £20. And it almost begs you to do neat things with it, to explore what it can do, make it do stuff other people haven't thought of.

Conclusion - if you know anyone aged 6 to 99, get them this for Christmas, together with a power supply, an ethernet cable, and HDMI cable so they can connect to their TV, and a USB keyboard and mouse (if you already have any of the above, use those). And an SD card (preloaded with Linux if you aren't going to be able to set that up for yourself).

 ... update 1 - perl is already installed on the Fedora distro.
 ... update 2 - sendmail is already installed, and I installed bind (to do DNS) by typing "yum install bind"

Saturday 10 November 2012

Milton Keynes, Blue series

The plan was to take the bike with me as I did this one, because it isn't a circuit, the route leaves you several miles away from where you started. I was planning to bike back along the road. I was hoping that A) it wouldn't rain, and B) there wouldn't be any fields full of cloggy claggy mud that you can't even wheel a bike across. I got lucky in both respects.

As I was going round, I saw this:

It looks sad, abandoned and lonely. If you see it, give it a hug.

Later on, I saw one of those.

There's a pole, and a string, and a bird-shaped kite on the end of the string, and it looked realistic enough that there were no birds on that field.

39 caches today, and a couple of DNFs at the end of the day.

Friday 9 November 2012

Swiftly the dentist

A few days ago, a bit of one of my back teeth fell out. So I saved it in a jar, and today I took it to the dentist. He had a look at it, and reckoned that it was filling, not tooth, which is very good news.

Then he sat me down, shoved things in my mouth, called for Polyfiller (or whatever it is they use) and refilled the tooth. No pain, no hassle, ten minutes, and there wasn't even any charge, because I'd been there less than two months ago to have my bridge put in (which is working very well, giving me a new front tooth).

I love the NHS.

Thursday 8 November 2012

A tangle of spam

I've been spammed by Action for Charity some weeks ago. I called them then, and spoke to a nice lady, who seemed to think that the worthiness of their cause outweighed the fact that they were in violation of the PEC Regulation (2003). I pointed out that no amount of worthiness should allow anyone to break the law, and that although I wasn't down on her personally, I did want them to stop spamming me. And she agreed to take me off their list. I also asked to be put on a blacklist, so that when they buy another list from another list vendor, we don't have to go through all this again. I think that requesting this has caused a number of spammers to set up what is called in the trade a "suppression list".

So I was mildly surprised (only mildly, it's happened plenty of times before that spammers continue to spam even after saying they wouldn't) when I received two more emails from them, and I phoned them up again to asked, politely, if they could kindly stop spamming me. I spoke to a nice man, who said they'd take me off their list. I also asked him where he'd gotten the list from, and he gave me a company name, which I shall not reveal for reasons you'll see soon. I'll call them Company X.

I visited that company's web site, and noticed A) they had a very strong statement of how ethical they were, and B) that they were a registered with the Direct Marketing Association. Huh.

So I called the Direct Marketing Association and gave them the details. They looked into it, and came back to me saying that Company X didn't have my email address on their lists, and hadn't sold my email address to Action for Charity.

So I phoned Action for Charity again, and left a message for the nice man I spoke to earlier. And I forwarded the email from the Direct Marketing Association to them.

Very soon, I got an email back from Action for Charity. The nice man had made a mistake, they didn't get my email address from Company X, they got it from Company Y. And the reason I'm not naming Company X, is they they seem to be innocent in this case. But the reason I'm not naming Company Y is that if the nice man from Action for Charity was mistaken once, he could be mistaken twice, especially as he also named Company Z in his email to me, and Company Z also seem to be an innocent third party - certainly Company Y say that.

Or are they? I got a spam from Company Z to another of my email addresses today. So they might be innocent in the Action for Charity case, but they're still spammers violating the PEC Regulation (2003), and I phoned them up to explain this to them.

I emailed the Direct Marketing Association to convey my regret that they'd been dragged into this by the mistake by the nice man from Action for Charity, but that it did underline the importance that spammers should attach to buying their spamable email lists from a vendor that's a member of their esteemed organisation. Certainly, spammers should buy lists of emails from disreputable scroats who are here today and gone tomorrow. And there are a few of those popping up and disappearing all the time, like quantum foam. Not, I hasten to add, that I include Company X, Y or Z in that category.

The nice man from Action for Charity also said that he was extremely dissatisfied with the list he bought from Company Y, and has reported them to the ICO (which I think means the Information Commissioners Office).

And Company Y has copied me in on an email in which he's threatening to sue Action for Charity for slander.

But all I want is for all these guys to stop sending me spam. Why is it so complicated?

More pieces of Pi

The case arrived today, the DVI-to-HDMI video cable, and the HDMI-to-HDMI video cable. A card reader that says that it reads SDHC cards arrived, but it doesn't read any of the SDHC cards that I have. Bah. And I found another 8gb SDHC card; this was hiding in the old Nokia smartphone, which I haven't used since I inherited Susan's iPhone, and which I probably never will use. I also installed Fedora for Raspberry on a 4gb SD card which isn't SDHC, so I was able to access it from the Linux computer, and fix it so that it has a static IP address - I think it already was starting up the ssh server, but I changed the default from graphic GUI on startup, to a text screen, because I'm not planning to use the GUI if I can help it. I also hunted out a powered USB hub and a USB keyboard.

All I need now, is to unwrap the Pi on my birthday and plug it in. But I doubt if it will be as simple as that.

Wednesday 7 November 2012

Getting ready for the Raspberry Pi

I decided to make another SD card, this one is 4gb and it isn't SDHC, so it reads fine in my card reader, and this one is Raspian, which is a Debian Linux aimed at the Raspberry - it's the default OS, so if the Fedora one gives me problems, I can try this.

Then I had a poke around. I mounted the card on a Linux box, which meant that I could access the Linux area; mounting it on a Windows box meant I couldn't see that partition. And all the familiar files were there, so I decided to do a bit more preparation.

From what I've been reading, most people seem to be using the Raspberry as a desktop-type computer; they want to add a keyboard and screen, and do stuff. But that's not really my main objective - I want to use it as a server.

So I've configured the start-up files so that it has its own, static IP address, wihch means I can ping it, and I've told it to start up sshd when it starts up, which means that I can log into it using ssh. And that means I won't need a keyboard and screen.

Also, the partition containing the Pi system is 2gb, whereas the SD card is 4; this means that half the space on the SD card is unused. So I'm using gparted on the Dell to expand the partition, so that they whole card is available.

Weight report 25

15 stone 9 1/4. That's under 100 kilograms, a significant milestone. But part of that is because I was afflicted with the squits.

Tuesday 6 November 2012

Faster DSL, a new windscreen and the squits.

One of my DSL lines was running quite slowly; 2 megabits instead of 7 or 8. So I phoned up by broadband provider, and they said the line was faulty. So I phone BT and reported that - they did a test, and agreed.

The next day, out came a BT engineer, tested this, tested that, and said "corrosion in the connection up the pole". He fixed that, and now I'm getting 7 megabits.

That's how customer service should work; well done Talktalk and BT.

Also, Paul from Glastech arrived and replaced my windscreen. Freda now looks great! And, more importantly, I won't get a lapful of broken glass at some random time.

I would have gone out today, the weather was terriffic. but I had to cry off at the last moment; a slight case of the squits. I don't feel ill, maybe just slightly achey, but I felt that it would be unwise for me to be more than a few yards from a good toilet at all times.

Monday 5 November 2012

More Raspberry, and Freda's windscreen

A small PCB arrived today, smelling faintly of Raspberry! Ladysolly's giftwrapping it for me.

A few days ago, a stone hit Freda's windscreen as we were bowling along the motorway, making a small chip in the screen. I said "Drat", or similar, and made a mental note to get it seen to before it became a real problem.

When ladysolly and I went to go out yesterday, the chip had turned into a full sized crack, and we decided that it wouldn't be safe to drive at full speed like that.

Today, I found out how much people wanted for a replacement windscreen. It was about £1100. But, as a special deal, I could have it for £800. Ugh. So I did a bit of Googling, and made a few phone calls, and I found a video of how to replace a Freelander windscreen by Paul of Glasstec Automotive.

So I thought, here's someone who knows what he's doing to the extent that he's willing to show people how, so I Googled Glasstec Automotive, got their number (0845 658 6545) and spoke to Paul. Yes, he can do it, and it's £375, including VAT, and that's for a Pilkington Glass windscreen, heated and with rain detector, just like the one I have now.

I could have gotten it slightly cheaper at Budget Windscreens, but I thought, expertise is worth paying for. He'll be round tomorrow to sort Freda out.

I also found that I can claim it back on insurance without affecting my No Claims Bonus. I'm slightly sceptical about that, but I suppose the insurance company take the view that the probability of a windscreen breakage is pretty much independent of how good a driver you are, and there's no way I could have avoided it, other than to drive very very slowly. So I pay the first £100.

And that, I think, explains why each person I called asked me if it was an insurance company paying - I'd guess there's a chunk added to the bill if it is, because in that case, I don't care how much it costs, and the insurance company can't be bothered to shop around for a better deal.

Sunday 4 November 2012

Burgess Hill

Out today with ladysolly. It rained almost the whole time on the way there, but I had confidence that it'd be dry when we arrived and so it was. Except underfoot.

On the way we stopped at the new Cobham services, and it's one of the best services around; a great choice of food.

We arrived at the trailhear, and squelched our way around three miles, finding all the caches except the bonus.

Saturday 3 November 2012

The birthday party

Ladysolly and I went down to London yesterday. We arrived at Marylebone and got the bus to Selfridges so that I could have salt beef sandwiches at the Brass Rail; now that Blooms and the Nosh bar are closed, that might be the best place for them in London.

Then another bus to Picadilly (and while there we did a cache), to visit Waterstones, which claims to be the largest bookshop in Europe. Maybe it is, but what I saw there was a lot of wide open spaces for people to lounge about on, whereas what I want in a bookshop is lots of books, so I think I still prefer Foyles. Still, I was able to find half a dozen likely-looking books.

Then on to daughter.1 for coffee, and then a bit later daughter.2 and bf arrived, and daughter.1.girlfriend, and then we all went out to supper where I ate too much, drank too much and had a good time.

On the train going home, I discovered that a bit of back tooth (or maybe a filling, I've lost count) has come out, so a trip to the dentist will be happening soon.

For my birthday (when I'm 64) I'll be getting a Raspberry Pi. I know this, because it's what I asked for, and I had to place the order. At RS they're £21.60 plus VAT, but RS are out of stock for a month (at least) so I bought it on Ebay for somewhat of a premium, and I also got the various bits and pieces to go with it (power supply, video cable, case). I'll be installing Fedora Linux on it, and if it lives up to its promise, I'll be getting several more to replace a bunch of aging servers that handle mail, DNS and other ancillary stuff. The Pi has no moving parts to wear out (my existing servers have hard drives that wear out and the power supply and CPU have fans that break down). Also, the power requirements will be *much* less; the thing that supplies the Pi with power is 5 volts, 1 amp, so it's 5 watts. The more traditional computers I use take 40 or more each. An 8gb SD card costs £4, and that's the "hard drive".

Thursday 1 November 2012


Following yesterday's disappointing weigh-in, I sneaked a quick weigh-in this morning, and I'm glad to say I was under 16 stone.