I'm sure it will look even better when the cables (on the right) are attached properly. We can't really make those cables live until work has finished in the currently dusty node 0.

In case you are wondering, the velcro is to give us the potential to use blackout blinds during the summer.

Since our cheap Maplin crimp tool wasn't really doing a great job, we decided to sacrifice the dawn and dusk sensor. Snip! Ideally, it would be nice to work out a sensor/resistor-like control since you should then be able to force the blinds open or closed. However, that will wait, for now we wired it up like the switch to an X10 universal module.

So it worked with the bare motor. For a proper test we decided to put the track up in the dining room - that's still full of boxes.

It worked and it looks pretty good too. I'd be nice to have more control than just momentary open/close/stop but it'll do for now.

We tested a bit at a time, but ended up with simple Perl script talking to the VIOM via the serial port. The VIOM was set to allow control of two outputs via the serial port (rather than the default of control via the inputs). The outputs were connected to the VIOM relay module. Finally the common and open of each relay output connect to the Centralis DC IB.

The blinds are controlled by a momentary toggle of the up or down output. This starts the blind moving and the Centralis keeps it going for a minute or two - long enough for the blind motor to reach it's limits (if only we could figure out how to set them). It is also possible to stop the blind moving by sending a momentary signal on both outputs at once.

We tested the Centralis with a voltmeter and it appeared to be doing exactly what we'd hoped. The motor voltage can be controlled through the up, down and stop switches on the front of the unit:

and through the two momentary electrical inputs on the back:

Sadly we couldn't actually get the motor running through the Centralis because we were trying to get away with using a 12V supply and it really requires 24V. I've ordered a 24V supply and hopefully we can get it working as soon as that arrives.

The most basic Dawn and Dusk model is most suited to automation - you can replace the dawn and dusk sensor with an X10 curtain controller. I ordered one of the curtain tracks (a 250cm one for 245 GBP), see Dawn and Dusk Autoglide Curtain Track. I didn't get the X10 curtain controller (88 GBP) as we're looking in to the VIOM for control applications at the moment.

We've also started thinking about using something other than X10 for some of the controls now. This was partly motivated by the number of X10 devices we would need to control the blinds. See Beanz's [future, ed.] post on the VIOM.

We know from the online manual that it runs at 12 or 24 vdc. After a bit of experimentation we get it to turn in one direction, but can't get it to rotate the other way. We think you need to reverse the polarity of the supply to change the direction (which we are doing manually), but it will only go one way. Reading the manual reveals that the plastic bits on the end of the motor are actually buttons that can be release to set the stop distance in each direction.

By playing around with the buttons we do manage the get the motor going in both directions, but we don't manage to set the stop distances - the motor seems to just keep going while it has power. At least we know that we should be able to control the motor if we can find a way to switch the polarity of power to the motor.

I do a bit of research and find that the name for something which allows you to switch the polarity of an output by activating two different inputs is an H-bridge. You can buy these for use in building robots. We're thinking of using X10, but this approach would require two X10 universal modules (or similar), one to make a circuit to raise the blind and one to lower it.

I try and find out what other people have done, but most seem to have bought the full kit.

Here's what I'd like to be able to do:

• Have all blinds in the house come down at dusk and go up after we've gone to work

• Have a blackout blind in our bedroom go up (behind curtains) in the summer to wake us up naturally (but not at 4:30 am as has been happening recently ...), this needs the motor to be pretty quiet, don't know if this is possible.

• Have the blind in our bedroom double up as a projector screen (high quality isn't a big deal for this). The blind should go inside the window with curtains outside for that cinema effect ;-)

After much googling it seems that Somfy pretty much have the blind market sewn up. Various of the automation sites sell blind kits that include Somfy motors.

Simply Automate have a one blind kit for 327 GBP which seems a bit pricey, especially when there's no proper automation yet. The kit includes an RF remote (not much use, we want central control from a computer).

I looked inside the kit and realized that the components are also sold individually. Interesting, which bits do I really need and which can be replace by cheaper bits. Well, the motor is certainly necessary and I'll need the aluminium to hang the blind on and the various bits to mount it. The cost of these bits came to 107 GBP + 6 GBP for 100m of bell wire which should do several blinds. The challenge was now to find out whether it was possible to control and power the blind for less than 200 GBP (roughly the cost of buying the other Somfy parts in the kit).

Before purchasing I wanted to find out a bit about the motor. There was surprisingly little information out there. It''s an LT28 DC motor and there is some information on the Simply Automate site and some on the Somfy site. Not enough for me to be confident that I understand how to drive it though. I decide to buy it anyway, hopefully it will come with more information.