PV plus motor plus worm drive is certainly an attractive route, but too expensive and not suited for local production and maintenance.
It needs to be really simple and so inexpensive that it's not worth stealing. For context, rural Somalia might be one of the target "market" areas.
On Apr 25, 4:47=A0pm, Morris Dovey wrote: [snip]
That's an easy one. Expanding gas cylinder like the greenhouse people use to open a vent. Hide it in the shadow of the collector itself, so when the sun peeks around, it starts expanding till it creates its own shadow again sortakinda like a wheatstone bridge but mechanical. When the sun stops playing peek-a-boo with the cylinder at night, it is brought home by its own collapse, perhaps helped by a counterweight/ spring. The cylinder would sit lengthwise along the obvious edge. It could sit in a slot in the collector itself for extra intensity. The mechanical challenge is minimal.
Maybe something bi-metal?
Slightly OT, but do any of you who play with gears have a suggestion for a package I could use to model simple-to-middling gearboxes, both CAD style drawings and also actual modelling where I could adjust the speed of an input shaft (or two) and see what happens?
I've been considering /two/ such gas cylinders (so that operation isn't air temperature dependent) - one on each side of the collector, each side connected to opposite ends/sides of a double-acting hydraulic or pneumatic cylinder. That setup would allow for an eastward pressure bias that would be overridden during the day, but would cause the tracker to revert to east-pointing at night, pretty much as you describe.
The major drawback appears to be instability in gusty winds due to the gas' compressibility.
Maybe, but I think your first idea is a better match to the problem.
Offhand I'm not sure how one would design such a thing but rather than using shaft work could you pump water from one plastic bag to another, with appropriate levers and paddles resting on top of the bags?
Maybe. I've been too involved in trying to help get the engine working to worry about the tracking system until now. Nearly all of my past experience with control systems has been digital, and I'm really in over my head on this one.
It seems to me that if I can choose one side to pump to, then I should be able to pump to a cylinder/piston linear actuator of some kind (thinking of a reworked shock absorber or strut) to do that job.
Hmm - if I use robatoy's gas cylinder idea to control a valve to direct part of the pump flow to one of your actuators, I might be on a better track than I am now, even though I'll still need to figure out some reliable way to make it face the morning sun without being vulnerable to nighttime gusts.
On Fri, 17 Apr 2009 03:39:52 GMT, the infamous "Lew Hodgett" scrawled the following:
Which one? _Practical Yacht Joinery_, which I bought, knowing full well that I'd be rich someday soon, or _Boat Joinery and Cabinet Making Simplified_?
Agreed, a stackable type of box joint jig is easily possible, it could only do one side at a time, unlike this one. Mathias' jig ROCKS!
------ We're born hungry, wet, 'n naked, and it gets worse from there.
Take your choice, it's in both.
Lew
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