£40.00 for the parts and then you have to somehow build it just pay the £120.00 on flea bay they are well worth it.
Well Tamnwill wasn't asking for a testamonial she was asking for cheaper options and for minimal technical knowledge you can make one which works well. I hadn't costed the simplest option but here it is if you can master the rocket science required to build it.
All parts are available on ebay and include postage and I haven't done any indepth research to find cheaper options.
7 day Mains timer (mechanical) £4.25
12V plug top ac/dc adapter £3.10
Aerial £18.00
Washing pulley set £ 4.00
Crock clips to attach to battery £ 1.70
Total £31.05
plus some scrap twin and earth wire and if you want to make a neat job so the antenna runs in a tube rather than being exposed add £2.25 or so for a 2 metre 1 & 1/4 inch waste pipe from Homebase. A few woodscrews and small bits of wood to mount the aerial and a 3m length of low stretch cord, an eyelet to tie the cord to the door and you're away. You have yourself a mains powered door opener and closer which operates off a timer.
The most expensive item is a brand new replacement aerial. You need to source one that has a slipping clutch and a limit switch and is ideally 900 - 1000mm travel, and is of the three wire modern type with +12V , 0V and up/down signal wires. You can use ones which have a 700mm travel but you need to use a double pulley system rather than a triple one. There are older aerial types still sold, sometimes called switch operated, which need a DPDT relay to drive. Simple to do but adds about £4 and requires a bit more knowledge. You can get scrap aerials for just a few pounds for even lower cost. I bought a 40 year old brand new old stock Philips one on ebay for about £8 which was perfectly fine for the job but you need to know what you are doing and can at least use a meter.
Even if you buy the commercial one you need to mount it and maybe relace the door so some practical work is needed. Building your own is cheap and fun and a whole lot more rewarding than handing out your hard earned cash for a commercial one. I've built 4 for under £100 using a common control unit all powered off a 12V battery I use for the electric nets. I charge the battery continuously. To do this with the comercial one would have cost inexcess of £500 so that's good sense if you are at all practical.
The photos show the door motor mechanism mounted on a Forsham Lenham. The pulley system is a three cord "block and tackle" arrangement converting the 1 metre antenna movement to 333mm movement of the door and reducing the pull load to 1/3rd so it easily copes wth the rather heavy door. The motor used here is a Philips 40year old aerial picked up for around £8.
HF