Solar Spinner - Magbot (200 rpm with no motor)

Cool Solar Spinner from Junk

Total Spend: US$ 0.75 that's right, 75 cents! everything else was recovered from old electronic junk

This solar powered ornament spins at up to 200 rpm in direct sunlight and was made in about 5hrs.

2 spinners in early morning sun. This instructable is for the rear one.

Parts:
1. Strip of circuit board
This was pulled out of an old stereo, and was used to mount a series of small buttons along the face, I would think that any low profile electronics would have something similar such as CD/DVD players

2. Inductor coil
I recovered this from an old 5.25" floppy drive. There were 6 on the circuit board. I think 3.5" drives may have something similar you could use. Failing that, buy a "Major Henry Coil" from Solarbotics.com

3. 2 x decent computer fans
When I say decent I mean ones that will have smooth bearings in them. Cheaper fans don't have bearings and are no use for this project.

4. Neodymium Magnet from old hard drive
Recovered from an old hard drive, this magnet is super powerful.

5. Solar powered Led keyring torch off e-bay
These are really quite cool. I bought a couple of these off e-bay for 75c each including delivery from China. I used the solar panel, a LED, a diode and part of the case.

6. 3904 and 3906 transistors
These are pretty common transistors and can be found in a lot of electronic circuits. Recover these from old circuit boards if you can, or if you have to buy them they are very cheap.

7. 3300-4700uF Electrolytic Capacitor
Very easy to find but if you can't, make up around 4000uF by putting smaller cap's in parallel. I ended up using 3 1000uF caps instead of the 4700uF pictured.

8. 1000uF Electrolytic Capacitor
Same as above

9. 1n914 or 1n4148 Switching Diode
Easy to find, they look like a little glass bead that's red inside and has a black band up one end. I found one inside the keyring

10. 2 x 100k Resistors (Brown, Black, Yellow, Gold markings)
I was lucky enough to be able to pull these off the circuit board above.

11. Sheet metal for a base.
Back panel from an old stereo in this case.

Step 1 Keyring Destruction

I recently puchased 2 "Solar Power rechargeble LED Flashlight Torche Key chain"
from e-bay for AU$1.00 each including free postage. That's about 75 cents US
each.

After about a week they arrived from China and I opened the packaging expecting
to have bought a couple of pieces of garbage. But was pleasantly surprised to
find a couple of quality items.

The LED's were quite a bit brighter than I ever expected and after pulling one
of the keyrings apart I found that it was a REAL solar cell. (I've picked up a
cheap solar powered calculator before that after pulling it apart, found that
the "solar cell" was just some painted plastic)

Desoldering was extremely easy as everything (even through hole components) was
soldered only to the surface. i used a hairdryer to soften the glue holding the
solar panel to the circuit board and was rewarded with..

3 bright white LEDS
1 germanium diode which I'll use in the circuit
1 2032 Lithium Ion 3.6v rechargable battery with handy tabs for resoldering to
something else
1 nice momentary microswitch
1 low light solar panel giving 4.5V and 10.0uA at 200 lux

a quick google search on the markings and model number ST-3722-9
revealed this information.
http://66.102.11.132/translate_c?hl=en&sl=zh-TW&u=http://www.ssetc.cn/product.asp&prev=/search%3Fq%3Dssetc%26hl%3Den%26safe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26hs%3DiHx%26num%3D50&rurl=translate.google.com.au&usg=ALkJrhj5bo101_6VxstDsH-SXp4VBsWfTg

Comments

[dzhang]

I couldn't find any inductors like that in a 5.25 floppy or in a 3.5 floppy that i took apart. I really don't want to buy an inductor cause i have all the other parts, so could you tell me how big your inductors were and how many ohms?

[zozzles]

The "Major Henry Coil" from Solarbotics.com is an extremely good piece of equipment, with a rather low price, The catalog states a "measured inductance of 1.03 millihenries" but to be honest, the strength of the magnet is just as important. Besides which, for this circuit that part of the design is somewhat overkill: It ought to work with parts of less quality. In a way, getting it to spin over the top the first time is the true test of things. After that, you've got a positive feedback loop going that is only limited by the bearing - and get this - the air resistance of the rotating arm! The triggering voltage to dump the current is usually at a hair's level from being high enough (almost twitchy, in fact), and you probably have more of a hassle coming up with a really decent bearing (i.e. low friction) than worrying about how incredibly spiffy the coil is: when the circuit DOES dump the current, it is going to yank the magnet toward it or the other way around. It is obvious that you've got the timing right. As noted, once you've got the (magnetic) polarities right, it works great. Although I wish that some of the photographs had been taken with slightly more light, this is an incredibly clever Instructable (and re-engineering of the original SolarSwinger) and I'm extremely grateful that you've shared it with us. I have no personal interest with Solarbotics whatsoever, but I've had extremely good luck with their service since 1997 or so.

[FreeBaseBuzz]

I don't think the internal resistance of the inductor is really important for this circuit. At a guess I'd say the coil is about 1 inch across and around 300-400 turns. You could wind your own... Hey, send me a personal e-mail to free.fly.buzz at gmail.com I may be able to send you a spare one I have in the post.

[maurice1993]

I'm sorry, I already didn't read your 'ible, but, looking by the pictures, this could be used has a ventilador, isn't?

[FreeBaseBuzz]

possibly.. I don't think it'd be too efficient though. it wouldn't spin anywhere near as fast with the drag caused by trying to push the air.

[maurice1993]

yup, but maybe, if I don't twist thw suport so much, just a little, the drag it'll not to be a spin problem, perhaps the air will not be pushed very well, but for a air recicler, I guess the air pushed it'll be not a problem... but I guess I never will had the answer if I don't make one for me...

[Bongmaster]

kool stuff :) I got some of those exact same torches :) one for keeps and 2 for the parts :P needed the panels for a solar fled engine ;) and those were the best and cheapest i found..

[FreeBaseBuzz]

Yeah, they are pretty good for the price, but I think you will find that they probably don't provide enough current to be useful for solar engines for bots. Your FLED engine will work, but it'll be a bit of time between triggers. These provide 10uA and you really need something in the mA range. I think these panels would only be good really for this kind of engine or building pummers. If you are doing motorised bot's, spend the money and get the solar panels from solarbotics.com, you won't be disappointed.

[Bongmaster]

well 2 of them panels seems to do ok on the one i made. but i have a few test solar engines in the make. seeing wat comes out best :3

[Tall_Tinkerer]

Great instructable,very well written and illustrated.