Help with a solar flip flap

Discussion in 'The Projects Forum' started by daddy-o, Jun 29, 2013.

Jun 28, 2013
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So my 9 year old daughter has taken an interest in electronics, so we have begun learning together. Still basic stuff, but going well so far. We took apart a "flip flap" solar flower the other day to see how it works, and it is a very simple circuit, but doesn't make a lot of sense. We want to re-create this circuit on a slightly larger scale, but are unsure what's happening. A solar cell feeds a capacitor, leading to a small electromagnet which I thought would need to pulse in order to get the flower's petals swinging. I don't see what is modulating the flow to the electromagnet though. Here is what it looks like:

There is another brand that does the same thing, but with a more complex design:

Can anyone point us in the right direction on re-creating what's happening here? Either version?

Thanks!

Last edited: Jun 29, 2013
2. wayneh Expert

Sep 9, 2010
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3,241
See that black glob? It contains the brain and is essentially impossible to reverse engineer. What you MIGHT be able to do is use the brain but scale up the other components. If you could trace out the schematic and post it here, someone might be able to help do that.

Jun 28, 2013
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I supposed that's what the black glob was about.
The second one we can see a few components, but that was a picture off the internet, so I can't get a better view.

So, Thinking trough this, what if we made a basic flip-flop circuit, but instead of the voltage switching between two LED's, it switched between the electromagnet and feeding into a capacitor which in turn fed back near the beginning of the circuit?

Jun 28, 2013
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My last post I think I am over thinking the problem.
Any thoughts on how image #2 would work?
I'm looking for better info on it. I'm going to see if I can find one that has that circuit to take apart as well.

5. MrChips Moderator

Oct 2, 2009
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3,453
Should be fairly simple to design.
The solar cell supplies current to charge the large storage capacitor.
A low frequency oscillator sends a signal of about 1.5Hz to the coil.

6. wayneh Expert

Sep 9, 2010
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Or does it watch the voltage on the cap and only trigger once it gets enough for a good pulse? If it's just a timer, then you should be able to increase the size of the solar cell and the capacitor and get up to maybe 2X or more boost in the magnetic pulse. More than that and I'd wonder where the next weakest link is.

I have a similar device (flying pig) and I notice it only really gets going in full sun. A bigger panel would help it be more vigorous in less-bright conditions.

7. THE_RB AAC Fanatic!

Feb 11, 2008
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They are usually just a relaxation oscillator, the solar cell charges a cap, and when the cap voltage reaches high enough it is discharged into the motor or solenoid.

Google for "photo poppers" etc to see hundreds of projects that people have made with a handful of simple parts.