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easy recharging method for child's toy Answered

I want to use a rechargeable battery inside a toy, and I don't want to remove the battery for charging.  I'm looking for a simple and safe method for charging that a young child can do by themself.  Here are some thoughts I've had:

wireless (such as with a qi pad) = Is there any way to actually keep this from getting hot?  I'm assuming the base would be always on, and the toy would be left on it all night or longer.

solar = This requires a light or the sun to charge.  I'm considering putting the solar cell in the bottom of the toy and making a light base that it could be placed on, but I'd need some type of sensor or switch so it only lights when the toy is on it.

metal contact pads = This would be easier than a plug since you'd only need to set the toy down, but can it be done safely?  

Anybody have suggestions?  Thanks.



4 years ago

Wireless? Probably the best idea, but not the cheapest. Use some ready made components and a charge controller for the batteries (you need that for any version, anyway). When no energy is transported (i.e. the batteries are full or the toy is absent) a well designed system should stay cool.

Solar? Good thinking. But the idea to put a solar cell at the bottom of a toy? Most of them are made from glass - and that is brittle.

Metal contacts can be made easily with pogo pins. There are versions with a rounded head. Of course you have to design the bottom of the toy and the base so that the toy can be set down with a wide error margin and slips into the correct position. A round base may be good (center pin to center pad and a second pin that contacts a ring on the toy) or a diamond shape wit pins and pads in the far corners and a bridge rectifier inside, so that the polarity doesn't matter.

I'd try to find a wireless system. It has the least design constraints (apart from the fact that you cant use metal as a housing) and the toy doesn't have to be set down to precisely.


Reply 4 years ago

Do you happen to have any sellers you can recommend for the wireless parts? I'd just be choosing somebody off ebay with no real idea what type of quality I'd be getting.

I meant the inside bottom for the solar cell, not stuck on the outside bottom. I was figuring I'd need to make some type of clear plastic actual bottom with the solar cell safely inside along with the rest of the guts like the battery.

Oooh, I really like the idea of the center pin and a ring. That should be really easy to get the toy placed properly. I'll probably do this if the other methods prove too expensive or impractical.



Reply 4 years ago

>Do you happen to have any sellers you can recommend for the wireless parts?

No, sorry. I only played around a bit with wireless charging (more power transfer). Did some tests with two loops (coils) and a function generator, but nothing productive and no store bought kits.