Solar 'gadgets' on ebay- ideas?

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Solar 'gadgets' on ebay- ideas?

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sally_in_wales
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Joined: 06 Mar 2005
Posts: 20809
Location: sunny wales

Posted: Mon May 16, 05 2:03 pm Post subject: Solar 'gadgets' on ebay- ideas?
On a whim I just bought a couple of these to play with. https://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=11737&item=5974552487&rd=1 I'm not expecting miracles when they arrive, but I thought with a solar panel, motor and switch all included I must be able to do 'something' even just as a novelty. Any ideas??

sean
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 42219
Location: North Devon

Posted: Mon May 16, 05 3:17 pm Post subject:
Greenhouse ventilation?

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Mon May 16, 05 3:20 pm Post subject:

It's a nice toy; I used to have one till I gave it to a friends kid to play with.

Most likely it's off-cuts from larger solar panels, and a four inch square will certainly shift a little motor around.

I've seen one used to power a little carousel ornament, and remember that with rubber bands and assorted wheels you've effectively got a gear system. But I can't immediately think of anything more useful to do with it.

You used to be able to buy this kind of toy in Maplins. Dunno if you still can.

judith

Joined: 16 Dec 2004
Posts: 22789
Location: Montgomeryshire

Posted: Mon May 16, 05 3:22 pm Post subject:
I have seen a similar set-up used to make a rotating plant stand to prevent your plants developing phototropism. On a very sunny day, it might make them dizzy though!

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Mon May 16, 05 3:28 pm Post subject:

Judith wrote:

I have seen a similar set-up used to make a rotating plant stand to prevent your plants developing phototropism. On a very sunny day, it might make them dizzy though!

Nice idea, but you'd want to play with gearing very carefully, and my gut feeling is that the motor might not be up to it.

How about making a little peristaltic pump with it for airating a pond or fishtank on a sunny day?

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Mon May 16, 05 3:54 pm Post subject:

- I note that the auction was just for the panel, motor and switch, so for ventillation you are going to need some sort of fan...
- and driving a fan is a fairly low-load, highish rpm sort of thing
- so, doing anything like real work is going to need some sort of reduction gearing, and while differing size wheels linked with rubber bands will make for gearing, the bearings may be a problem. (You've not got much power, so losses become very important)
- I think pumping seems like a reasonable sunlight-modulated task
- presupposing a pump, you might consider a mini solar water heater, or by encouraging evaporation a cooler, or a pond pump, or a mini irrigation system for when you're away from home...
- by connecting the two panels in parallel, you should get more current out, which will allow the motor to deliver more torque useful for driving real loads (oh and more heat too!)

A peristaltic pump, essentially like squeezing toothpaste from a tube - but the tube is long, and the squeezed bit arcs around a driven shaft, can be fairly low tech... but isn't the force required going to be a bit high, even with two 4" panels...
Have you got any Meccano?

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Mon May 16, 05 4:26 pm Post subject:

dougal wrote:

A peristaltic pump, essentially like squeezing toothpaste from a tube - but the tube is long, and the squeezed bit arcs around a driven shaft, can be fairly low tech... but isn't the force required going to be a bit high, even with two 4" panels...

Depends on the tubing. If the section of tube you're working on is really thin and quite flexible then you might get away with it.

sally_in_wales
Downsizer Moderator

Joined: 06 Mar 2005
Posts: 20809
Location: sunny wales

Posted: Wed May 18, 05 3:10 pm Post subject:

Well, they just turned up and I'm well impressed. Contrary to expectation all the fan mechanism is there too, and they are silent an quite powerful little fans. I'm going to use these to create a through draft on a cold smoker. I think the idea is going to be that I build a firebox some way from the smoker and mount the fans in the top of the smoker to draw the smoke over the food. Sound plausible?

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Wed May 18, 05 3:26 pm Post subject:

sally_in_wales wrote:

Sally, that sounds ingenious. Please keep us informed on whether that works!

Will you really need fans to create a flow? Aren't you better restricting airflow?

sally_in_wales
Downsizer Moderator

Joined: 06 Mar 2005
Posts: 20809
Location: sunny wales

Posted: Wed May 18, 05 3:49 pm Post subject:

I was thinking in terms of sucking copious amounts of smoke steadily past the food, and creating a slight draw to keep the smoke box going- albeit from a distance. Thinking of using an army surplus ammo box for the smoke box, drill a few holes to allow air in, but use the draft from the fan to create the draw and pull the smoke past the food. At least, thats what I think I need to do in this instance. Will have to play with it and see, but if it works I end up with an easily fired up and damped down smoker that can sit in the garden on a cool bright day and just get on with it.

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