A thorough exploration of the very retro perpetual motion style ornament that was HUGE in the 1970's, and still lives on with little difference to the circuitry.
A starter search on eBay would be:-
https://www.ebay.com/sch/i.html?_from=R40&_nkw=magnetic+perpetual+motion&_sacat=0&LH_TitleDesc=0&LH_BIN=1&_sop=15
Target price $12 to $20.
The technology is very similar to the solar powered rocking ornaments, but they actually use a dedicated blob-chip that has self starting ability due to a voltage threshold trigger that can pulse a coil to try and get the pendulum started, and then uses the same coil to detect the swinging magnet and nudge the threshold of the coil pulser.
This older technology uses the brute force of a big magnet travelling at high speed over a large coil to trigger a single transistor directly.
I'm not sure why they don't use a flyback diode across the coil to protect against the coil's back EMF (ElectroMotive Force). I'd guess it's because these ornaments are all based on an original design. I don't think there's a drawback to doing the modification, and it didn't seem to affect the operation of the pendulum.
Magnetically maintained pendulums are fascinating. A lot of fun to build and they can run forever with a solar panel topping up a small cell. Long decorative pendulums make a very pleasing wall ornament.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
A starter search on eBay would be:-
https://www.ebay.com/sch/i.html?_from=R40&_nkw=magnetic+perpetual+motion&_sacat=0&LH_TitleDesc=0&LH_BIN=1&_sop=15
Target price $12 to $20.
The technology is very similar to the solar powered rocking ornaments, but they actually use a dedicated blob-chip that has self starting ability due to a voltage threshold trigger that can pulse a coil to try and get the pendulum started, and then uses the same coil to detect the swinging magnet and nudge the threshold of the coil pulser.
This older technology uses the brute force of a big magnet travelling at high speed over a large coil to trigger a single transistor directly.
I'm not sure why they don't use a flyback diode across the coil to protect against the coil's back EMF (ElectroMotive Force). I'd guess it's because these ornaments are all based on an original design. I don't think there's a drawback to doing the modification, and it didn't seem to affect the operation of the pendulum.
Magnetically maintained pendulums are fascinating. A lot of fun to build and they can run forever with a solar panel topping up a small cell. Long decorative pendulums make a very pleasing wall ornament.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
would it be possible to re-design the circuit so that the back EMF of the coils collapsing field
would provide a momentary 6V pulse in Lieu of the batteries and be actually self contained?
Does anyone else emember the point of purchase advertising displays from the 1960s that used the same 'technology?' Usually a large cardboard-backed product image on a stand with an oscillating subsection to attract attention. Loved those as a youngster ๐
Clive, Q: Can one not add some components to the BEMF voltage. To then power a rechargeable battery which will then power the original circuit to repeat its cycle, to repower itself?
That was interesting. Instead of getting rid of the back emf why don't you dump it in a battery?
inductive kickback
Very interesting ๐ง๐ด๓ ง๓ ข๓ ณ๓ ฃ๓ ด๓ ฟโก๏ธ
Hi, I love the interest you bring to this breakdown. Can I ask what you do for a living?
Is the steel core necessary?
Question: The rise on the back end of the trough of the pulse: I have a hard time understanding how the rise could represent the approaching magnet: the magnet only approaches once, yet we see four pulses! The magnet approaching is evidenced much more subtly as the long gentle rise leading the first of the four pulses (magnet is moving wayy slower than the slew!). Still not sure what the rise you are talking about actually is though! I would guess it is a harmonic of the coil / tensile stress of mechanical assembly, combined with the mostly, but (keyword) Imperfectly static impedance front-ending the junction. Junction temperature? Am guessing the reactance is showing up as (hysteresis?)…. which will be described by the impedance…. and eventually the voltage on the scope screen. The "ghost note" is probably a fifth above the coil resonance (assuming this is true) because it looks about 1/3 of the length of the trough. Good eyesight on on the trough representing the coil resonance frequency… I almost wonder if this device or similar would be a "quick, easy, & dead accurate" way to measure a coil's resonance peak: something about conventional active measurement seems too "particular" to the impedance of the semiconductor as in conventional "sweep+look@level" method. (via the unique impedance of the osc/test jig.) Really having trouble wrapping my mind around the flyback to begin with! Do you think the chatter would be specific to the type of transistor, if it were arbitrarily substituted?
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I haven't seen Kodak alkaline batteries in a while. When I was testing batteries for longevity. Kodak lasted the longest. Panasonic came in a close second tied with radio shack alkaline. Good video. it takes a lot of patience to reverse engineer something and draw a schematic. I think I might get one of those toys for my desk. It will go good next to one of those bobbing birds that continuously bobs its head to drink water.