Exploring wireless LEDs with schematic and waveforms

[@acidhelm]

Let's appreciate how Clive turned all 100 LEDs right side up before starting the video. :D

[@DannyGruesome]

It hurt when he scooted them and they tumbled around

[@two_tier_gary_rumain]

Nope, he missed one. 5:37 Look to right of the bottom of the lot (5 o'clock position?). There's one on it's side.

[@SuperOrang3]

Let's appreciate how the commenter took the time to count the LEDs 😂

[@owlredshift]

@@two_tier_gary_rumain who is this comment _really_ for? Other than yourself

[@leef_me8112]

@@owlredshift Now that I came back to visit, I appreciate the accuracy. @Gary Rumain

[@mikeselectricstuff]

Another fun thing you can do is use different cap values on different LEDs, so they resonate at different frequencies, so you can have a few seperately controllable channels.

[@jkobain]

That's a really neat suggestion!

[@jamarforsythe7262]

Would this be sort of like having them twinkle when quickly changing frequencies if they are all in the same coil?

[@amojak]

The coil is very low Q though so frequency discrimination is poor. The idea is good if you were to change the led circuit so it can be higher Q a d better match the LED impedance.

[@KeritechElectronics]

@@jamarforsythe7262 might be possible to use frequency modulation and a low Q coil on the transmitter side, and high Q coils of slightly different inductances for various receivers.

[@sebrassino]

That's a good idea. You're good at thinking out of the box.

[@DirkFedermann]

the first thing that came into mind, seeing the coil and how the LEDs behave, was a riddle for an escape room or something, where you have maybe a pattern of LEDs shown, some will not light up, some in different colors etc. and you have like a magnifying glass with the coil in it.

[@Sheppey05]

My exact thoughts!

[@leef_me8112]

Why did you have to tell everybody? ;)

[@mfx1]

I was just typing the exact same idea and then thought I'd better check other replies....... I would also add an earlier stage of the game that "activates" the "magic" magnifying glass.

[@PsiQ]

@@mfx1 yep, the classic first step of blood sacrifice and selling your soul, gets people in the right mood for beeing trapped in a room.... ;-)

[@epmorris]

I was thinking some kind of interactive exhibit/sensory experience where a wand could be waved over strategically placed LEDs would be cool. Fun patterns could be made with different colours or flashing LEDs.

[@mikeselectricstuff]

I played with this stuff a couple of years ago. Having the cap for a tuned circuit makes a significant difference to performance at lower signal levels. If the signal is weak, the resonance will build up over multiple cycles until it reaches the Vf of the LED. It will work without, but much better with. A fun variation is an RGB LED with coils at 90 degrees to each other - colour varies with the orientation of the unit in the coil

[@Peter_A1466]

That's cool! Did you make a video of it?

[@bigclivedotcom]

That RGB version sounds good. Definitely a good call for a short video.

[@mikeselectricstuff]

@@Peter_A1466 Never got round to it - didn't think of the modelmaking application - could probably have made a few quid before the Chinese took over!

[@rfburns5601]

@@bigclivedotcom You measured 223khz - the inductor/capacitor resonance of the 330pf & 220mh coil is: 1/(2*pi^sqrt(220^-3 X 330^-12)) = 186Khz. Looks like resonant power transmission, kinda like radio!

[@mojoblues66]

Saying you're not sure if this is a tuned circuit is like saying you're not sure what the frequency dial of a radio tuner is good for. This is basic electromagnetic transmission.

[@IanSlothieRolfe]

The 2.2mH inductor and 330pF capacitor have a resonant frequency of 187kHz which is very close to the 222KHz you saw this oscillating at, so the capacitor is clearly there to make the efficiency better by resonating the coil.

[@TheBypasser]

"187kHz which is very close to the 222KHz" "Very"? :P

[@markusgeimer3099]

I'm so glad I found a video of Sean Connery teaching me electronics!

[@6F6G]

The LEDs have 2.2mH inductors and 330pF capacitors. Their resonant frequency is 187KHz. Try swapping the capacitor to 240pF (220pF would do and more common) to get a better match to 220KHz the coil puts out.

[@dylanlowe3570]

I know this is an older video that came back into my playlist, but it is interesting to see that the seller on AE was so impressed by your video that they have incorporated it onto their marketing on the sales page.

[@AmusementLabs]

That magnifying effect would be PERFECT for some kind of interactive queue element or activity at a Disney or Universal park. Like gem searching for kids.

[@aaronbrandenburg2441]

Yes would be cool if done some sort of way like that or something somewhere

[@Coderandpainter]

It was such nice how you explained it, although i didn't understand much but i found it better then most of the electonics Taught in my university.

[@BRUXXUS]

Wow, I've never seen those little lights before. Being assembled directly onto the SMD inductors is super cool! Might be a neat way to do light up clothing.

[@superdau]

It won't work well for clothing. The two coils (transmitter and receiver) have to be "on axis" for power to be transferred. You'd have to ensure that the coils stay aligned, which will be really hard to do with clothing, unless you're talking about something rigid ("cosplay armor"?), at which point you might as well use wires.

[@BRUXXUS]

@@superdau I was imagining more like, have a few of these sewn into a small section of a coat or jacket, sealed in resin to make it waterproof and washable. Have a little pocket on the inside where you could place the coil and battery when you want to have lights. My thought was more that it's an easy way to have the power source completely removable so washing and waterproofing would be easier. :)

[@chuckoneill2023]

@@superdau Maybe, but if you're adding dozens to the armor-- for a cosplay S.F. character, as an example -- this installation could be simpler than wires. Also, if it flexes somewhat, the intensity would change as you move. Of course, as Clive demonstrated, these things aren't all that visible, except in a dim room -- like, say, an S.F. masquerade.

[@kuhrd]

@@superdau With a small tesla coil running several feet away they might light fairly well. I have not tried it with these but I know you can do it with just the lead length of standard LEDs and a zener diode with a small tesla coil and light LEDs wirelessly from 4-5 feet away.

[@jamesfirth7795]

@@BlondieHappyGuy shouldn't that read "OMG, HE'S LITERALLY FABULOUS!"

[@wtmayhew]

It is definitely a resonant circuit. 5 uH and 100 nF resonates at 225 KHz. Ignoring the capacitance of the LED chip, 2.2 mH and 330 pF resonances at 187 KHz. The parallel capacitance of the LED would probably drop the resonant frequency. The coil driver seems to be right on spec. The little LEDs seem like they’re a little off peak resonance, but that might be intentional to tweak the voltage across the LEDs. Right on resonance might be too much voltage. The Q factor of the ferrite core inductor and chip capacitor combination is probably fairly high given the type of components, thus the voltage right on resonance will be fairly high. The air gap makes the mutual inductance quite low and the little LEDs function almost independently more like radio receivers in the far field of a radio transmitter rather than primary and secondary windings of a transformer.

[@mikeselectricstuff]

The voltage is always clamped by the LED, so you never get more than one half-cycle of resonant rise. The high DC resistance of teh fine wire in teh coil also limits max LED current.

[@wtmayhew]

@@mikeselectricstuff Excellent comment. Thank you. It is still interesting they aren’t matching resonance of the driver coil and the LED assembly. I was presuming the Q would be fairly high, but you’re right, that is pretty fine wire, probably with appreciable resistance. Maybe they have the resonance offset so there is less variation in intensity versus position with respect to the driver coil. I am assuming the LED junction in parallel with the 330 pF has appreciable capacitance and that would lower the resonance of the LED assembly to less than 187 KHz.

[@mikeselectricstuff]

You don't get any more light from inverse-parallel - with a single LED, the energy can built up over the non-conducting half-cycle and gets dumped into the LED on the next - with inverse-parallel LED, you just get half the power, so no net benefit

[@Peter_A1466]

Are the leds effectively flashing rapidly? Or more or less fluctuating in intensity (fast)?

[@gazzaka]

DO you get more light from parallel universe?

[@Peter_A1466]

Only if connected in series

[@JWH3]

This depends because perception is as complicated thing. Humans are sensitive to peak brightness so with equal power a pulsed source can look brighter than two dimmer sources even if it's producing less light. We perceive a brighter light but if you were to measure it with sensors you'd get different results. Luminous efficiency of LEDs is also not linear so a lower average current will be more efficient than pulses of higher current electrically. This would be a little complicated to demonstrate because the currents are pulsed at a high enough frequency. You would need a photo detector with a fast enough response time and then average things properly keeping in mind the weird distortions out perceptions place on things.

[@Peter_A1466]

I was not expecting visible pulsing. Was more wondering if the capacitor more or less smooth everything out or not, since this seems not the primary task of the capacitor in this circuit.

[@mikemike7001]

One way to think of how this works is to consider the big coil to be the primary winding of a transformer and the little coils to be secondary windings.

[@graealex]

And an even better way is to see them as a tuned receiver, because this is not a transformer.

[@leef_me8112]

@@graealex Air coil transformer?

[@graealex]

@@leef_me8112 Transformers usually aren't resonant, and don't require any tuning. The best comparison would be a Tesla coil, although the C part of the LC isn't that obvious with them. The circuit being resonant is what allows it to transmit over several cm and significant amounts of power. Anyway, the transformer comparison is as appropriate as saying your VHF/DAB radio at home is the secondary side of a big transformer, with the primary side being the big radio transmitter.

[@rickjljr11]

@@graealex A resonant LLC power supply has a tuned transformer to take advantage of the efficiencies of zero voltage switching. Lm of the transformer is part of the tank circuit.

[@graealex]

@@rickjljr11 Obviously you can always add capacity, and it remains intrinsically a transformer. Or add semiconductors and make the behavior completely non-linear anyway. In the context of energy transmission, it's still closer to a tuned receiver. If the receiver isn't matched to the transmitter frequency, no energy is received. There is one example of wireless energy transmission that actually is nothing more than a simple transformer, and that's with electric toothbrushes. Especially since they operate directly at 50/60 Hz instead of in the kH-range.

[@andrewarmenia1461]

The capacitor and tuned circuit may be there to achieve "zero-voltage switching" of the MOSFET. When the MOSFET turns off, the current flowing "downwards" through the inductor will first charge up the capacitor. When the voltage across the capacitor rises high enough, the inductor current will be driven back to zero, and then start flowing in the other direction, discharging the capacitor again so that the voltage across the MOSFET is back to nearly zero when it turns on again. This is the half-cycle of a sine wave you see in the scope traces. But I wouldn't have thought ZVS would be necessary at such low power levels... edit: it probably helps to protect the MOSFET from high back EMF without just dumping the energy through a diode.

[@rickjljr11]

I think that also. At 11:29 note how they tuned the circuit so it switches when the voltage on the capacitor is zero (looks like < 1 Volt). all the energy of the resonant circuit is in the inductor and starts getting added to

[@rickjljr11]

Unloaded is there about 3 Amps peak to peak between the inductor and the cap?

[@o0OMouseO0o]

Have you tried to make a much larger inductive loop and see if a larger area can be made active?

[@bigclivedotcom]

I wanted to make the video before blowing the module up, but will be doing further experiments.

[@Vosentech]

Yes! Our company designed and released a wireless light set with a much larger active area in case you are interested :)

[@DCBpower]

Try making shapes / letters. What a cool sign to have the LEDs on a belt rolling over the magnetic lettering. Encapsulated, they could be in the stream of a fountain with a large coil in the pool.

[@johndododoe1411]

A larger loop would have different inductance, thus needing a different capacitor to get the desired resonance frequency.

[@KonstantinGrigoriadis]

The Leds with the LC Circuit form a Tuned Circuit and draw energy from the Electromagnetic Field of the Transmitter, like a Grid dip meter does.

[@SirBoden]

I still instinctively close my eyes when you say “watch your eyes “. 🙏

[@BradTech.]

The way you ran it across like a color revealing magnifying glass there at the intro was spectacular!

[@aaronbrandenburg2441]

Crazy idea but gender reveal party?

[@DrJacull]

You make my science day more enlighten & wirefree.. Nicely done ..... brilliantly explained.

[@Black3ternity]

0:24 - you can see the white LED that is pretty far away from the coil lights up. Seems that this one picks up stray energy and seems to have some "problem" because it starts flickering and such. Interesting stuff.

[@robertalabla]

Just built a low buck version with 3mm red led, 330pf ceramic, and 1mH axial inductor. Works a treat. Thanks Clive!

[@masterblaster9123]

I like how you print up the circuit boards because it's a good teaching tool and it can be utilized in education

[@masterblaster9123]

I want to use the design of this and superpower it with high voltage and elements to charge

[@masterblaster9123]

I wanna see if I can excite atoms in certain materials and see if I get some results and also wireless charge batteries with reciver capps

[@rfdave3980]

I have made these and use these for years testing switch mode power supplies in car radios and instrument clusters. I put clear heat shrink tubing over top. Excellent work Big Clive

[@Opel_Guy]

That coil is a bonded coil. There is a coating on the outside of the wire (bond coat) so when it's being wound, there is a heat gun close to it so the wire bonds together and holds it's shape.

[@jordanclarke2996]

Timing of this video for me was great. Just been playing around with some inductors and a new lcr meter! Thanks again for another great video!

[@Wabajak13]

I don't understand anything this channel or these comments talk about but boy do I find them interesting.

[@nicholasboyarko1680]

I've had my eye on these for a while but haven't purchased yet. Thanks for the breakdown, now I don't have to do it! It's one of those things that's neat, but I cant think of a practical application. The current being so low, the potential applications are even more limited. Could be cool for something wearable or a simple indicator light based on proximity. Now, if you could push a good 20W through this, there's tons of other applications.

[@Vosentech]

Hello! If you are looking for a ready-to-use solution, we've released a more powerful wireless light set which you can see on our channel :)

[@mikemike7001]

Adafruit also sells a set with a larger, 20cm coil that runs on 24V and 10 wireless LEDs, which unfortunately is currently and most often out of stock.

[@Nono-hk3is]

They also have a 12 volt model with a middling sized coil. Also chronically out of stock.

[@bigclivedotcom]

I was going to link to the Adafruit ones until I realized they had no stock.

[@hagensu1748]

If you need it. You can try my products

[@hagensu1748]

kzbin.info/www/bejne/a17Em6Cco5dnoK8

[@kimmy_future4265]

Thank you for the warnings when you bring the light back on! My photosensitivity appreciates it.

[@MelissaMaya]

I reviewed these things some time ago, and made a video to teach people how to build themselves their own LEDs... glad to see you also reviewed them. All sellers uses the small CD43 inductors, but i made some with smaller CD32 ones, and still works fine (a bit shorter range, i think remember). The original ones, the X-Base (Cross-Base) are quite expensive, the double base was about 200€, and then 10 or 15€ for a 10 unit pack... if you bulk buy them to aliexpress is quite cheaper. Also, you can coat them with some epoxy to water proof them, and maybe run them underwater (in a fish tank perhaps...). Bigger bases gives wider range, the one you have is the small version, there's another with 20cm diameter coil.

[@Vosentech]

Hey! Our company has actually just released a more affordable wireless light set at less than half the price last week, take a look at our channel if you are interested :)

[@nickc9788]

@@Vosentech ehh, 25 LEDs and a coil for $100 isn't half price

[@freakyjason477]

I've made the equivalent of these using some NE-2 neon indicator lights. Just get a big enough inductor. Guaranteed proof of concept is the primary winding from an old 9V wall-wart on top of one of those Qi charger pads. Just connect the NE-2 bulb across the coil and you're in business.

[@piconano]

I calculated the resonance frequency to be 228.77 KHz. Your demo shows it to be close enough. The ones with the caps produce more voltage and hence light up sooner. Also, inductors with this many turns, have al lot of capacitance all by themselves.

[@Chris_Grossman]

The capacitor does form a tuned circuit that enhances coupling. If you had a grid dip meter you could show the enhanced coupling.

[@pepethefrog7193]

Today we have $50 graphical antenna analyzers from china :)

[@AdityaMehendale]

The enameled wire is usually coated in a secondary "hot glue" resin that can be melted by putting some i^2*R power into the copper once the bobbin has been wound. I have also heard of ethanol or IPA-activated glue-layres. It has no electrical function; just mechanical.

[@KeritechElectronics]

Food for thought - of course :) Given that the best energy transfer occurs when the capacitor and coil reactances are equal, i.e. the circuit is in resonance, you can calculate the resonance frequency: f = 1/(2*pi*sqrt(L*C)) Manipulating the inductance or capacitance on the transmitter side without first changing the generator frequency will lead to energy losses and transistor overheating because of impedance mismatch, and doing the same on the receiver side will result in too little energy being delivered to the LED to light it. So, both sides have to be tuned to the same frequency.

[@johnmiller0000]

Surely, if you drop one - just turn off the lights, energize your coil and scan the carpet!

[@Peter_A1466]

Where is my Tesla-coil...?

[@axel_is_gaming]

Love your videos. Always informative. Maybe one day you can look into those old keychains that were ringing when you whistled so you can find your keys, or maybe GSM controlled power sockets.

[@triodehexode]

That looks like it will be fun for LW and MW wireless listeners next door.

[@masterman7033]

A few things about this video. First, I was so happy not being greeted by ads at the beginning or being interrupted by them during that I let the ads at the end play in their entirety! Second, great content! I routinely fabricate a variety of wireless power transfer coils and supporting circuitry in a variety of configurations and sizes. I embed them in everything from epoxy resin to objects in motion. Tuning your opposing coils via capacitor increases coupling therefore increasing efficiency and thusly power transfer. In this video the ferrite cores of the inductors play a critical role in the coupling effect. Sacrificing size, power coupling could be increased by further rectification and increased tank size say via 1uF to 10uF capacitor.

[@peter.stimpel]

For the interested ones: atomic14, a scottish youtuber, was playing around with those, as well. He made an attempt to self build the LEDs in one of his videos.

[@DCBpower]

You can hook a small coil up to a function generator and sweep the frequency rang to find the optimum frequency to power a single LED. But by having the optimum frequency of the LEDs dissimilar to the coil, each LED will have very little impact on the driving coil. Operated at perfect resonance, a full circle would put a heavy load on the coil and alter the output of LEDs already inside the coil.

[@pufango4059]

I thought of a similar system when I was about 12 years old (1972) to light up an off shore light houses .To save having to use electric cables in the sea ! My teachers were totally dismissive of my suggestions ! Just think I could have been a genius ! 😁

[@svrs]

Requesting video of the same concept but using omnidirectional holo diodes. Great content. From your vids I've learned a lot as though remembering what I already knew, not that did already, but is actually a reflection on you as being an excellent communicator and teacher. your content is appreciated!

[@teardowndan5364]

The LEDs with capacitor light up first because the voltage of a parallel LC circuit will creep up under excitation until leakage offsets input energy, classic signal detector circuit where you pick LC for your center frequency and Q-factor (Xc/R) for bandwidth. The higher the Q, the more sensitive the circuit is at the expense of narrower bandwidth. The non-LC LEDs light up when inductive coupling into their inductor produces high enough voltage.

[@EggBastion]

and if it's iron it goes _err, err, er err errr errrgh_

[@Lazy_Tim]

Way more than I needed to know about these lights but very much appreciated.

[@kyoudaiken]

This literally does look like magic although it isn't. The product images also look like they're conducting some kind of ritual. I love this tech!

[@WilliamWallace14051]

It would be interesting to see the oscilloscope traces across the coil for the various versions of LEDs.

[@PaulSteMarie]

It would be, but tricky to probe without the ground acting as a second receiving coil. If you took the hook off the oscilloscope probe, and used the little spring probe ground that goes right on the point, you might get it to work.

[@johnriker3940]

Agreed...

[@GadgetBoy]

The resonant inductor for that capacitor is an order of magnitude smaller. 2.2nH

[@matthewhopson964]

Thank you so much for posting this clive. This is exactly the sort of thing that we have been waiting for. Low brightness is hardly ever a consideration, Quite the oposite1

[@BaudirenergieDe]

The receiver coils have the wrong capacitor value. It should be around 231pf instead of 330pf to match the forced frequency of the transmitter. The transmitter coil with its capacitor can also be tuned to improve consumption and efficiency. It actually only runs at a forced frequency determined from the driver, but not in matched natural LC resonance. Thanks a lot for your videos!

[@bigclivedotcom]

330pF is a standard value.

[@fazergazer]

Came for the oscilloscope traces. Stayed for the ambiance! ;) Another circuit made possible by the power of MosFETS!!

[@ericoppel5698]

These remind me a bit of back in the 1970's when I discovered that if you held onto one end of a fluorescent tube and held it up in proximity to high voltage power lines, or held it next to the antenna of a CB radio which was transmitting, it would glow! :-)

[@codebeat4192]

I have an idea, make an analog clock with a inner ring of LEDs for seconds and outer ring for hours and a ring in the middle for minutes. You need three pointers (actually a cheap clock) with coils for this that rotate above the surface. When a pointer with a coil moves along it lights up a LED.

[@leef_me8112]

'Tis been done with Neopixels.

[@eDoc2020]

I recently designed something like this except hardwired, using only old-school logic chips.

[@paulsengupta971]

It would probably be easier to do it with magnets and reed/hall effect switches.

[@codebeat4192]

@@paulsengupta971 It is not about ease, it is about the effect. I can imagion surrounded leds still glow a little when the pointer is off center to a led. So you will get a fade-in fade-out effect. This effect cannot be done with reed switches. I think this is easier to make than what you suggest. You can buy those leds with the coil attached. Soldering and wiring isn't required.

[@codebeat4192]

@@leef_me8112 The fun is, you don't need logic or programming for this.

[@singlefather01]

The capacitor is there to calibrate the resonant frequency. The receiver and the transmitter both should have their resonance at about the same frequency.

[@paulcabrelli1863]

these are very fascinating to play with. Got some a couple of months ago.

[@bobcat_the_Lion]

It may be very well a resonance circuit; 2.2 mH + 330 pF gives about 187 kHz, which is near the 220 kHz you measured. It would also explain why the LED with the capacitor removed was dimmer at first. 5 μH + 100 nF is 225 kHz. It all matches up. It will also mean that a larger coil, or one with more windings may perform worst.

[@blacksmock445]

5uH +100nF would have a very low Q-Factor. Looks like this is yet another source of Radio Frequency Interference. 225kHz was a frequency allocated to the UK for Radio 4 in Central Scotland, but there was too much interference from Poland. I believe that the Polish transmitter has already, or is about to close down.

[@flapjack9495]

@@blacksmock445 What would cause that particular combination to have a low Q? In this case that might be a feature since a low Q would mean it would mean a broader bandwidth, right? You wouldn't have to be too concerned about getting the frequency matched just so.

[@pyromaniac303]

They'd be better feeding the output of the xkt001 into an audio amp or H bridge to effectively double the voltage swing of the output without increasing the supply voltage. I did something similar with an NS8002 audio amp and oscillator.

[@blacksmock445]

@@flapjack9495 Since the frequency seems to vary with the load (number of LEDs used) a High Q wouldn't be desirable. A radio tuned-loop antenna circuit would probably use an inductance of around 1.5mH with a capacitance of 365pF. Both of these components would have much higher reactances at resonance and a higher dynamic impedance and a higher Q. The combination of 5 uH and 100nF wouldn't make a very effective tuned-loop antenna for radio reception on 225kHz. They would be a lot easier to make if it did.

[@amojak]

The small inductance and large cap on the sender produces a low impedance tuned circuit with low Q, in cost terms it saves money on wire too.

[@martin_mue]

Now you have to build a lavalamp with these LEDs floating in silicon oil.

[@MatthewPurnell]

It looks like the price of the coil has gone up a bit on the aliexpress page, and they seem to have taken a frame from this video (5:04) as a demonstration of what it looks like full of LEDs

[@party4lifedude]

One different idea this gave me is what if this was used in some kind of escape room. You have a "magic" magnifying glass that simply has one of these transmitter coils in the rim, and you have to look for clues which will have these lights hidden inside of them and will glow when you examine them.

[@VictorF0326]

I saw the same demo for plastic models like gundams instead of using traditional battery powered LED compartments. Pretty damn nice not replacing those batteries

[@TheManThatCan1002]

It would be interesting to see something in like an escape room that used a pattern of these and a "magic magnifying glass"

[@ShadowzGSD]

been waiting for you to have a look at these, knew you would sooner or later. i would end up losing them and having to go around in the dark with a coil to find the darned things.

[@MrAsBBB]

Loved this a lot. You are the best at what you do. So well done……

[@bunnykiller]

besides a tuned Tesla coil, one of those inductive heaters tuned to them also may work too...

[@SanDiego619RS]

Looks cool 😯

[@phonotical]

I've done this without any circuitry, just feed it straight, works totally fine, I've also used it to transfer audio!

[@stefanlavriv8119]

I'm thinking to create a resonant circuit and putting it under plastic or aluminum clock hands. The coil must accommodate several led diodes in the middle. Hands must be minimum 5mm wide to accommodate coil + LED's + capacitor. All that put into classic quartz clock driver, driving coil under clock face and you got glowing clock hands

[@holderbee7811]

Howdy Clive, must admit I'm fairly new, usually don't ultimately understand the 'schematic' part.. but this time 'gave it a go' and....... was somewhat confused on the colorized PCB... some things were making sense.. others werent.. until.. realized I had basically got the polarities switched vs marker color.. finally got it though, and thanks for the good work

[@GreatJoe]

Yeah, 2.2mH and 330 pF puts the resonant frequency at a bit over 180 kHz. The LED would then lower the Q far enough that it'll catch 220 kHz just fine. LC tank circuit resonant frequencies are easy enough to calculate by hand, and you can get online calculators to calculate them for you anyway.

[@theadventuresofzerotomillions]

Thanks you for warning me you were turning the lights back on. Lying in bed, that could have been uncomfortable. Gentleman status achieved.

[@McTroyd]

Wow. If' you'd shown these to me ~30 years ago, I would probably still be talking about them. Seems like it could be a good teaching tool for RF and tuned circuits. Maybe couple your blue/violet LEDs with phosphor silicon or resin casts?

[@Northern5tar]

Me trying to replace the LEDs: "Look I made a molten blob!" Somewhere in between that giant bulb you showed the other day and these microscopic thingies is my comfort level. :) Very neat though.

[@ooslum]

These are really interesting Clive but the only thing I can think of using them for is a model fairground in a Michael Bentine style without the flees. Cheers

[@Incognitus-Umbra]

Thanks Clive, love this video

[@donaldasayers]

I calculate 186KHZ for the resonant frequency of the LEDs and 225KHz for the driver coil plus capacitor, so it is not beyond the possibility that there is resonant coupling.

[@KRiley129]

Wonder if it could drive a color changing led or if the circuitry in the led would be too sensitive to reverse polarity.

[@superdau]

No, you can't. Color changing LEDs need a (somewhat) constant voltage. But you only get pulses with this one.

[@a1nelson]

@@superdau Edit: the following was referring to LEDs with multiple _controllable_ colors - which I’ve come to understand was not the OP’s question at all. So, I added a second reply. The original comment follows, in case part of it might be useful to anyone else. I’m not exactly sure if the question relates to the LEDs in the video, or if it’s more general. So, I’ll focus on the latter. If the multi-color LED is serial (e.g., NeoPixel, WS281x, APA10x), common cathode or common anode, then yes, it’s impractical to impossible. However, multicolor LEDs are also very readily available (I’ve used them in production) with separate anodes and cathodes. As such, it’s trivial to wire one color channel in the “positive” orientation and other/s in the “negative” orientation. I can confirm that a sine/square/sawtooth/etc. wave imposed on this setup will, indeed, cycle color as the polarity of the wave oscillates. Not that you’ll notice if the frequency is >20 Hz or so - and certainly not at the 240-ish kHz shown in the video. In response to the question about reverse polarity, typical LEDs have zero problems with reverse voltage of up to 5V, but I’ve used them at much higher voltages (~170V) without any issues, at _low_ current. If you’d like extra protection against reverse polarity, just add something like a 1N4007 diode along with the LED. (This also reduces the voltage by ~0.7V.)

[@superdau]

@@a1nelson RGB LEDs are not the same as color changing LEDs (as asked about in the OP). Color changing LEDs have an integrated logic circuit, which needs continuous power to work properly.

[@bigclivedotcom]

It would need at least a diode and capacitor to provide enough current to ride over the zero crossing points and avoid resetting the LED.

[@a1nelson]

@@superdau Ah, yes. I didn’t initially read the question that way, but I see that your interpretation is very likely correct. I’ve mostly seen that style referred to as color _rotating_, but both terms seem reasonable. I believe Clive’s take is on the money - need a cap to keep the internal circuit from resetting. I’ve used color rotating LEDs in 5mm format before, but only on an experimental basis. I was curious if they’d always start with the same color. At least some do not (sample size of a paltry one or two). However, even with some have a pseudorandom starting state, you’d still need a cap to prevent it from constantly shifting to other colors - ruining the effect. From memory, I think they’re also a bit slow starting. Maybe part of their internal operation involves an RC circuit of some kind. Pure speculation.

[@bocoroth915]

Interestingly, the aliexpress link you provided seems to have added a cropped screenshot from this very video to the listing to show what lots of lit LEDs look like.

[@Quickened1]

Brings to mind a couple questions... First, how large a coil could one get away with, possibly overdrive it? And, it would be interesting if you shaped the coils, i.e., formed to a square, triangle, star, etc, could you effectively manipulate a large layout of leds to conform to the shape? In conclusion, would led reverse parallel circuitry result in better performance overall? Cool stuff Clive...

[@Quickened1]

@@BlondieHappyGuy indeed...

[@Vosentech]

Hello! We actually just released a read-to-use wireless light set with a much greater use area, if you are interested take a look at our channel :) Our LEDs will work at up to 30cm away from the base

[@Quickened1]

@@Vosentech I like to see someone doing something productive with these! I imagine a much larger coil can be made for industrial, commercial applications as well, as in several meters in diameter. I like the forward thinking, much like mine, I just don't have the capital, to capitalize on my own ideas! Best of luck to you...

[@Vosentech]

@@Quickened1 Thanks for your feedback! Large coils would certainly be pretty cool (there are a few videos on KZbin where people have have up normal-sized light bulbs from across a room but as you increase the power/size of the electromagnetic field, it also increases the risk of it interfering with other devices which is why this technology hasn't been upscaled (although Nikola Tesla certainly envisioned such a world where everything would be powered wirelessly). We definitely plan to make a larger version of our wireless LED system but there is a size limit at which you would start to exceed emissions limits. For our current system, it is however infinitely expandable as you can place many of our wireless power bases near each other to increase coverage.

[@Quickened1]

@@Vosentech yes, it's a brave new world... I was thinking rather than having to drive one giant coil, multiple coils could be sandwiched side by side/end to end, into a single housing, which should balance the overall power required and theoretically, reduce consumption, and interference issues...

[@sparkyprojects]

You have a tesla coil, the primary is a tuned circuit with the coil and capacitor bank, the secondary is not so obvious, but the top load is one plate of a capacitor, planet earth is the other plate. If you change the tap point or the size of topload it won't work properly. The primary and secondary are resonant circuits. the ones in the led system is a parallel tuned circuit, just look at any radio circuit diagram (plenty online)

[@jyvben1520]

nice effect, grandfather clock pendulum could hide the coil, leds on the back of glass , altered weight might ruin time keeping part ... but that is adjustable ?

[@JWH3]

Wind yourself a bigger coil, try it out see what it's limitations on deformation are before it can't power it, I think the reason those stock coils are flat is because these are meant for like posters or models so you can put that under a layer of paper behind the model that's begin lit. It's quiet fascinating though because if it can light an LED it can run a low power micro controller, man I wish I owned my own silicon foundry :) I think you can use multiple coils if you position them properly as well, depends on how much extra loading on that driver will handle. Experimenting with that stuff will start to irritate nearby HAM operators fast though :) these things are noisy in the low AM bands.

[@aaronbrandenburg2441]

Good point I was thinking about RF interference with other radio services and more

[@Vosentech]

Hey! Last week, our company released a ready-to-use wireless light set which has a much greater operational range if you are interested :)

[@misterhat5823]

Both the tuned circuits on the primary coils resonate at roughly 200kHz. So, I'd assume the capacitors are to make a tuned circuit.

[@jotatsu]

mmmm, what about doing a "lava lamp" with those leds floating up and down?

[@Super1337357]

Since the wave is asymmetrical would flipping the big coil over cause the other anti-parallel led to light first?

[@bigclivedotcom]

I'd expect so.

[@HalvardSkurve]

Does flipping the big coil upside down affect the brightness? And (at 14:36) does the opposite of the reverse parallell LEDs light first then the coil is flipped?

[@graemezimmer604]

The transmit circuit is a bit odd. The usual way to drive a resonant coil from a square wave is to connect the tuned circuit in series, because a series tuned circuit has a minimum impedance, so you get higher current. Using a parallel tuned circuit is odd because it is a high impedance at resonance, plus the low resistance of the FETs will swamp the tuned circuit. It would be worth hooking the TX tuned circuit in series to see if it gives greater output. You would probably have to retune the capacitor however. And presumably the receiver coils are in parallel because the higher voltage is needed to light the led.

[@fpvangel4495]

White being the fusion centre of the spectrum the orange/yellow and green/yellow parts of the colour spectrum should be the brightest as its harnessing from 2 colour short circuits which produce the white - Walter Russell, cool stuff Clive. :)

[@acmefixer1]

Clive said, "they will roll and you will not find them." That is, until you bring out the neodymium magnet you got out of a hard disk drive and sweep the floor a few times. As long as they're ferrite they should stick. Have you ever done an episode on LED throwies? Thanks.

[@two_tier_gary_rumain]

You could also run a coil over the floor in the dark.

[@TopEndSpoonie]

The listing now says that it comes with 10 LEDs. Shows as AUD$10.94 which is £5.79.

[@milan72]

can this LEDs work with wireless charger?

[@bigclivedotcom]

Yes. But no communication, so they just pulse.

[@Orxenhorf]

10:45 - What in the world is causing it to drop lower than its steady low level at the end right before if jumps to high???

[@petehiggins33]

The MOSFET is being turned off at that point. To turn it off fast you have to pull current out of the gate by shorting it to 0V or better still driving it negative. Most of the Gate current comes out of the Gate-Source capacitance but some of it comes from the smaller Gate-Drain capacitance which tends to pull the Drain slightly negative.

[@tonysheerness2427]

You will find the dropped led when you wake up in the middle of the night to go to the loo, when you are half asleep ans stomp around in bare feet. The pain will remind you not to drop them.

[@Leroys_Stuff]

Kinda brings back memory’s of ants and a magnifying glass

[@pglick123]

"Seemed like a good idea at the time."

[@NeneExists]

I'd be really interested to see if the addition of a capacitor back to the double LED units gives them even better range

[@dflood6111]

One of those mini lamps was very effective and was lit up despite where the loop was....

[@electronics-by-practice]

nice exprementation , you can use that wireless led to diagnose a power switching supply just put it over the transformer , an other idea if you decorate you clothes with many of them you will light up when you pass a walk through metal detector.

[@paulspaws1521]

I think we will see them in little character model's with the coil in the base would be kinda nifty to have little wireless lights on them