Selling Up

Back when I lived with my parents, I had a great time building various projects, which even won me a car. I put a lot of hard work and money into building a rack from scratch, creating a whole-house-audio system from various parts along with the software, and wiring up the house for networking.

Well, the time has come to dismantle many of my projects. My parents are itching to put my old room back to use, and I need to gather as much cash as I can for an exciting excursion to the other side of the world next year. I have felt some tears forming, but I just remind myself what it is in aid of and all of the unknown projects that are yet to come.

I have started listing much of the equipment on eBay. If you’re interested in home automation, want to build your own rack, or you have a professional need for some of the AV equipment then please take a look and bid on things that take your fancy.

More equipment will be added tomorrow – mostly the PCs that I no longer use. This includes 2 rackmounts and an old gaming rig.

Power monitoring with CurrentCost

CurrentCost monitor

The CurrentCost power monitor has become very popular amongst amateur home automators and those technically-savvy who want to keep an eye on how much electricity they are using (and ultimately how much they are going to have to pay in bills). A couple of months ago I purchased the CurrentCost device and a USB cable to connect it to a computer from eBay. Having just seen their eBay store, it looks like they’ve got a fantastic new model on the way, but this article is about the older version.

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Source code for the VAMS-0808 serial interface

As promised, here’s the source code for my VAMS-0808 interface. It’s in C#, with C# projects included, and can be opened in Visual C# Express or full Visual Studio 2005 or greater. There are two test projects included – one which just writes status changes out to the console, and a WinForms project (which runs in mono) for full interaction.

Whole House Audio system: version 1 is complete

Over a year after it began, the whole-house-audio project is complete. 4 rooms around the house can now be filled with the sound of any of (currently) 4 audio devices thanks to a mixture of hardware and software.

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Low voltage power supply, ventilation & lighting

One thing that has been lacking since the first build of the rack is ventilation. With both sets of doors closed, the inside can get quite warm, especially when iron is turned on. Not any more though, having just completed the installation of 2 active ventilation zones, lighting and a low voltage power supply system complete with rack-mount control panel.

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The audio system that I’m building requires 2 low-power computers: 1 for the touchscreen controller (not using an iPod Touch for the moment) and 1 to act as a webserver and serial-console server.

Once again eBay has come to the rescue, and by searching for ‘geode’ – a low-power processor for Thin Clients & Small Form Factor (SFF) PCs – I found the 2 machines that I needed. These are the specs:

magnesium (the black one)

  • 800 MHz Geode
  • 256 MB RAM
  • 6 GB CF drive
  • Onboard graphics, audio, serial, parallel, USB & 10/100 ethernet

70 + P&P

potassium (the grey one)

  • 300 MHz Geode
  • 256 MB RAM
  • 6 GB 2.5″ IDE drive
  • Onboard graphics, audio, serial x2, parallel, USB & 10/100 ethernet

35 + P&P

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Alternatives to DVB-T in the UK

Here in the UK there are a few ways to receive digital TV. Some of them are free (after an initial outlay for equipment) others are based on a subscription model. Here are some of the most common ones:

  • Digital terrestrial, received through a suitable TV antenna (DVB-T)
  • Cable, in most cases through Virgin Media (DVB-C)
  • Sky (DVB-S)
  • Freesat (DVB-S/DVB-S2)

My MythTV installation is currently solely using a dual-tuner DVB-T receiver to record TV. However we are right on the edge of the closest transmitter’s reach with no usable overlap with any other transmitter, so at best our signal is spotty.

As spring progressed and the trees regained their leaves our signal has gotten weaker and weaker to the point that about 90% of recordings fail due to a lack of a signal lock or a very weak signal producing something that’s unwatchable.

The TVs in the house cope slightly better, but still suffer a lot from a broken signal. With digital being all-or-nothing compared to analogue’s degrees of static snow, it’s either you can watch something or you can’t… unless we change to the analogue tuners in the TVs, which we often have to.

We are being forced to consider alternatives, either to back up terrestrial or replace it completely.

I’m keen to keep to things which can be used legally with MythTV, which would rule out Sky and Virgin Media which essentially bind you to using their hardware. The benefits of those two services however is that they have a more complete selection of channels as well as the option to upgrade to significant bonus content, compared to the one remaining alternative – Freesat.

Freesat was launched recently by a collaboration between the BBC and ITV. Most of the transmissions are in Standard Definition (SD) with a small sprinkling of High Definition (HD) services. More channels are expected to sign up, but at the moment there’s all of the UK BBC and ITV channels plus Channel 4 but at the moment no Channel 5 (who seem to insist on transmitting encrypted signals). Also there are none of the UKTV-owned channels including Dave.

Freesat is transmitted unencrypted over DVB-S & DVB-S2, both of which can be received by a computer using an appropriate satellite receiver card. Naturally I’ve been keeping my eye out on eBay for such cards, and there are usually a few on at a time. I’ve not bought any just yet and I won’t until a decision is made for sure that we’re going for Freesat rather than the next alternative, cable.

DVB-S2 is used for carrying HD programmes. It is relatively new, so although there are PCI cards out there cable of receiving the transmissions, the software for Linux hasn’t caught up yet. MythTV is in the early stages of including support, and some basic drivers are available. The cards come with software for Windows, but that’s not much use for a distributed MythTV-based PVR. I’m hoping that at least I can get DVB-S working for recording and such, then upgrade to DVB-S2 when it’s reliable. In the meantime HDTV can be watched on a normal set-top box.

Before Freesat came on the scene, as already mentioned the next alternative was cable from Virgin. In my investigations it quickly became apparent that connecting a DVB-C card (a rare thing in the UK) to Virgin’s cable network was not a good idea since it would almost guarantee disconnection of all services including my 20 meg broadband.

To keep within the T&Cs of that means using the analogue output from the V or V+ box, connecting it to a capture card and then doing digital->analogue->digital conversion. The result of this would be relatively low-quality video and audio, at a limited resolution (SD only). An IR transmitter would need to be used to control channel changing, and since it uses the only externally-available tuner you couldn’t watch one channel on TV and let another record on the same box. It’s certainly not an elegant way of doing things.

If we were to go for Sky, a similar thing would probably have to happen, although with a little work it may be possible to get a PCI DVB-S card to work with it, provided it had support for a decoder card so that the signal could be decrypted.

In the likely event that we decide to go for Freesat, the cheapest solution would be to do a complete self-install. However the easiest solution would be to pay for installation of a single-room service. We will need a 4 room service however, so the plan is currently to pay for a single room installation at £80, then buy a quad LNB and run the 3 other cables ourselves. That way we don’t have to worry about getting the correct size dish, mounting and positioning it. Apparently there’s some satellite-grade coax around somewhere that should do the job.

There will probably be 2 tuners in a machine that will do the recording (possibly boron) and the other 2 runs will go to the living room and the master bedroom.

Naturally there will be photos and such if/when the project takes place.

Almost there with the audio system

Yesterday I completed and successfully tested the control software for the audio system. The software works with the matrix switcher and the APC MasterSwitch remote control PDU to allow the audio output devices around the house (TV, radio, CD player etc.) to route their sound to any of the 4 audio zones.

I’m now waiting on some more purchases from eBay to arrive before I can finish the system off. On the way is a small touch-screen monitor and a low-power mini ITX computer to connect it to. This will function as the controller and will probably sit in the dining room at the centre of the house. I’ve not gone for an iPod just yet, since a small mobile device has the possibility of getting lost or damaged more readily than a fixed controller. I’m looking out for a cheap 2nd hand one on eBay though.

Although I had got the software working yesterday, I foolishly installed some updates for Ubuntu and now the serial ports have disappeared again. Rather than battle to get the ports to show up and behave I’ve gone a little more eBay crazy and bought a second thin-client-like low power PC which will run the matrix control software and possibly the web server for the front-end control interface.

The other remaining tasks include creating some more cables and positioning and attaching the speakers for zone 4, the master bedroom.

Full details of the setup, with a video, will hopefully be posted in the next few weeks.