Query - solar power and electronics project

Cut one of the wires you had going to the LED when it worked, and insert the switch.

Thanks for your prompt reply: I've just had another look at it and it was just a dodgy wire connection: its working great now.

Cheers

I had a similar situation. Bought 4 solar powered yard lights from WalMart for under $20 total. Removed the stakes, rigged hooks using coat hanger wire, and hung them up in the tree out front. Great yard lights and the neighbor's kids cant get at them.

Luhan

Helluva good idea, particularly for AZ.

Do you have model number information?

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

The box may be around here somewhere. Just check the garden section (indoor) at your local WalMart for the best deal. You can also find similar deals at Home Depot lately.

The units come complete with a pair of AA nicads, solar cells, charging/switching ciruit, and a one really efficient LED. You could not possibly make one for the price they sell at. I have, however, considered buying them just for the solar cells.

Luhan

Hello Luhan,

Any idea of the wattage of those solar cells? Are they easy to remove?

Are the AA cells of the solder tab variety? That would be nice because once in a while one goes down in lab equipment and tabbed NiCd are hard to find locally, and expensive. Actually it has become very tough to find any NiCd locally. It's all NiMH and those often don't like 0.1C trickle charging.

I never liked those stake lights, they don't even come close to a 4W Malibu light and when I look around the neighborhood they seem to die quite fast. But for getting at those parts that may be another story. I guess you could even make a cell phone or radio charger for back-country hikes.

Regards, Joerg

I investigated solar power a bit:

I don't know if the LED is "really efficient" as Luhan said.

Mine came in a rain-proof transparent dome. I could take them out, but then I thought why bother.

Mine were not.

NB they need replacing about just over once a year (around 500 cycles).

I don't think they were adequate as illumination, just okay for path marking.

In the US I expect you can get very far from cell phone masts. Radio might be nice after a day's hike. GPS unit and a LED torch might be most useful.

Hello Kryten,

So far I wasn't too impressed with LED lighting. A nice halogen bulb is better IMHO. We have one of those "flashlights" with a car headlight bulb in there. Really bright.

Well, if they are at least NiCd that would already help.

There is a time delay limit AFAIK. However, in remote areas we still have analog networks and those can go a long way. A radio is cool. Once we took a shortwave radio down into the Grand Canyon, only to see how well you can receive stations from Europe way down under the surface of the earth. It worked and sure enough a soccer game was on. The ranger came by to check and walked away shaking her head before we could explain that this was only a "scientific experiment".

GPS? Nah, I am an old-fashioned map and compass guy. But we did have a few cold ones in our back packs, only the good stuff, of course :-)

Regards, Joerg

I can't determine by surfing... are these yard lights smart enough to turn off the light and just charge the battery during daylight?

...Jim Thompson

Yep, I got 2 kinds. One has an obvious CS photocell for low light detection, the others seem to sense directly off the solar cells. They all don't turn on until its dark enough to notice them.

Generally, they don,t provide much illumination, just act as markers for sidewalks and pathways. Also, they switch to a lower power mode to run thru the night if they can't do the time at full power. Not bad engineering for under $5 each.

Luhan

They are embedded in clear epoxy but could be removed as a unit.

Don't know about you, but I've been soldering onto all kinds of batteries since I was 10. Buff the ends with really fine sandpaper, use an 800 watt iron, and just get a dab of solder to stick, then back off fast. After that pre-tin the wire and sweat solder the two together. Yep, I'm still here to talk about it!

Luhan

using

yard

Illuminated Targets ... ;-)

remove?

The garden lights I ripped apart - specifically for the solar cells - the cells gave out a decent and useful 4V at 20 mA in full sunlight. The solar cell assembly can be pried off with a knife with a bit of care - the cells are epoxied onto a PCB that is glued to the lamp with hot-melt glue.

Hello Frithiof Andreas,

Thanks. 80mW is decent power, plenty to keep small motes and stuff like that afloat. Hot glue is no problem either, it usually isn't very strong.

Regards, Joerg

I find a 25W one just fine. sand, making sure the sandpaper is absolutely clean. add a little flux, build up a blob of solder on the iron, and touch to the battery, back off, leave cool. Tin the wire, push against blob, and repeat so that the wire sinks through the blob. You should touch the cell for a total of maybe 1 second, and it should be touchable in 5 seconds after you do the joint.