The Undead Remote

In the very late 1990s, something amazing was invented. White LEDs. These magical pieces of semiconductors first became commercially available in 1996, and by the early 2000s, you could buy a single 5mm white LED for less than a dollar in quantity one. A year or two later, an astonishing product showed up on infomercials airing on basic cable at 2 a.m. It was a flashlight that never needed batteries. With a small white LED, a few coils wrapped around a tube, and a magnet, you could just shake this flashlight to charge it. It’s just what you needed for when the Y2K virus killed all electronics.

Of course, no one uses these flashlights now because they suck. The early white LEDs never put out enough light, and charging a flashlight by shaking it every twenty seconds is annoying. There is another technology that desperately needs a battery-less solution, though: remote controls. They hardly use any power at all. That’s exactly what [oneohm] did for his Hackaday Prize entry. He created the Undead Remote.

The dream of a battery-less remote control has been dead since your parents got rid of that old Zenith Space Command, but here it is. This is really just a shake flashlight, a diode rectifier, a large capacitor, and some glue. Shake the remote, and you can change the channel. Is it useful? Certainly. Does it look weird and is it slightly inconvenient? Also yes. But there you go. If you want an easy way to deal with batteries in your remote control, this is a solution.

30 thoughts on “The Undead Remote

  1. Back in 1973-77, I worked at Burstein-Applebee in KCMO behind the “electronics parts” counter while going to college to get my BSEE. We sold some Zenith TVs and that remote you mention used a air-bladder bellows to blow on some untrasonic whistles that were received by the TV. A cleaver idea. You won’t believe how may people came in to get “new batteries” for that (the rubber bladders had cracked)! Some of the TVs back then, like all the garage door remotes of the day, used either the new” tech 45V (back then) or “old” tech 90V batteries plus a couple of AAs for the RF transmitter’s tube filaments (I think the 90V batteries had a filament voltage output).

    As for those shaker flashlights — when one “died” on me, I opened it and found CR2032 battery in it. I expected to find a supercap, but there was none, just a regular electrolytic. The CR2032 had died and once it was replaced, it “worked” again.

    1. I have one that uses a small NiCd. I left it on until it went out then turned off the switch and started shaking. Took a lot of shaking to get a charge in the battery. An interesting thing about that one is the magnet hovers inside the coil when the light is held vertically. Jiggle it and the magnet bounces up and down without hitting either bump stop. I could make a vertical mounting clip for it for a vehicle and it’d self charge from vibrations. I’ve thought about swapping the LED for a newer, more efficient one to get brighter light.

      I also have a fake one. It has the rectifier diodes and other components on its PCB and the coil form is wound about half full but not connected to anything. In place of a magnet it has a crudely cut hunk of plain steel rod. Where the NiCd battery would be is a coin cell.

      Then there’s the ones in between real and fake. They have a really small battery (or capacitor?) soldered to their PCB *and* two coin cells. The magnets are real and the coil is connected. Shaking the light with the switch on makes it flash brighter, but I’ve not gotten them to work without the coin cells. Dunno if the circuitry actually works to charge the little battery (or capacitor?). The plastic parts of the light are cheap polystyrene, like the fake one. Unlike the good one that’s made of some other plastic.

    2. That wouldn’t have been a Zenith TV. Those used remotes with metal rods struck by hammers. That would have most likely been a Magnavox Phantom.

      The Phantom blew air through a pair of plastic whistles with different high frequencies. Put one to your ear, press the buttons and you’ll hear a quiet ‘chuff’.
      These remotes are completely ignored by almost every “History of the TV Remote” article, including ones on HaD. Also, I’ve been unable to find any pics of the inside of one.

      Magnavox did make a wireless electric remote under the Phantom name, but it preceded the air whistle type. I did find one photo of one opened up. It’s all capacitors and resistors mounted on terminal strips. Classic pre-PCB stuff.

      How about someone obtain one each type of Phantom remote and be the first to do a teardown and examination of how they work?

      1. I believe you are correct, and I stand corrected. When I said that, I could not recall if BA ever sold Zenith back then, but I do recall BA selling Magnavox which had recently (then) been purchased by Phillips in the Netherlands.

  2. How impractical would it be to build some “shake batteries” in AA and AAA format? Since most remotes take 2 or even 3 batteries, you could make one of them just be a supercap to store and deliver the energy, and the other one or two could be shake-generators.

    1. It’s a matter of getting a rare earth magnet, and some super fine wire. But figuring out where the cap would be is going to be the hardest part. Not a lot of room in that size. Maybe if they run in series you can make one the “generator” and the other the capacitor.

  3. I applaud the idea here, but I don’t recall ever needing to change the batteries in my remote.
    I just checked, and the TV I bought more than 10 years ago still has the original Sony batteries.
    (And I suspect I am unusual in keeping a TV for longer than 10 years)

          1. Sorry, no more guesses left. As I already wasted the 3 guessing attempts (stick, phone, mind).
            But RF as in bluetooth? Cool then you need to pair you remote with your TV first, but in order to do so you must turn it on first… using the remote. Nope, can’t be bluetooth (just kidding).

            Regarding line-of-sight IR. it actually isn’t line of sight. My remote also works when I point it away from the televison, for instance by pointing it towards the wall behind me. The IR light simply bounces of the wall and hits the receiver from there, works even better then directly pointing at the $@$%@ settopbox. IR is simple, works pretty low tech, dirt cheap to produce. Can’t see why they want to abandon this concept.
            Then again… the audio jack was also dirt cheap, proved to be functional for many many decades was very low tech. it was impossible for me to think of a situation where this would be removed from any device.
            Then somebody realized that they could sell more converters chargers and add-on by removing this device and replace it by something that has far more possible point of failure, the most common… empty batteries or unable to connect. And when it fails completely… much more expensive to replace.

            I still hope that ‘1’ will inform us about the new way of remote control…

          2. LG’s magic remote is definitely RF, I think it does IR for power only so you can actually pair it the first time you turn on your TV but I wouldn’t be surprised if a lot of smart TVs worked the same now.

    1. i don’t think I’ve ever owned a TV long enough to change the remote batteries, now that i’m forced to think about it, cable box remotes however must all have a flaw that causes the ether to leak out…

  4. My aunt and uncle had one of those Zenith TVs with the ultrasonic remote. One time it started going crazy; it’d zoom in and out at random, or the volume would go up and down, channels change, that sort of thing, when no one was using the remote.

    Turns out, they had an ultrasonic pest repellent device plugged in. As it swept through the frequencies, the TV’s functions would get triggered.

  5. Philips also has those remote wall switches for its Hue ™ system that generate the required energy from the “click” of the switch itself, i assume it’s facilitated through the piezo effect.

    And since they use ZigBee, I imagine it uses quite a bit more energy than just flashing an led really fast for a couple of microseconds (controlled from dedicated single-purpose silicon).

    So .. someone make a flashlight i can just hit on a wall to charge.

    1. I remember seeing a prototype of such a device that repurposed the piezoelectric striker from a lighter. They used it to briefly power up a microcontroller and transmit something using on/off keying…

      No idea how many total coulombs one could get out per use, though.

  6. I am thinking more along the lines of some heat pipe going into a thermopile on one end and a heat sink on the other. You stick the heat pipe in any conveniently available orifice or even in your coffee (perhaps with a wipe down depending on which orifice had been used last) and Vola, you have a convenient source of power. It would make a very humorous flashlight, being powered from where the sun don’t shine.

  7. I had a two function remote unit from an Zenith tv that relied on a button causing a hammer to strike an ultrasonic tuning fork. I hooked it up to control lights in the room and accidentally found that different coins thrown on a table would activate it. No batteries, just a pocket full of change!

    1. When I was a child, in the early 60’s my grandparents had a Zenith TV with the space command and the tuning fork remote for it. Back in those days the dealer would program the TV for you. If I recall correctly you a button or two for the channel up or down, and I think 3 buttons for volume settings. The channels had to be “programmed” into the TV. The front panel of the TV had the up and down channel buttons as well. No random access.

  8. one fun unintended side effect of those acoustic remotes was that ultrasonic motion detectors, dog collars, or any other source of noise could make your TV do funny things that you’d run yourself ragged trying to hunt down – if you want a fun “remote” to look inside the early “Lazy Bones” was an interesting solution to a problem that didn’t need solved, one tube, a 90V battery and a rotary encoder (think rotary phone) to change the station on your fancy new console radio

  9. Wow feels like white LEDs have been about forever, i feel old.

    I too had a TV years ago which had a sound based remote, i remember being fascinated by it as a kid as i noticed that unlike other remotes id seen it had no IR on it, i then noticed the high pitched sound that came from the remote and cracked it open to find out what was going on, i still love seeing the ways old tech did things we take for granted these days

  10. Eccentric (aka vibrate) motors from old phones with a ZVS setup work. I came up with a design that uses active rectification so that hardly any energy is lost in the switching. Use something like a 2N7000 for this, lower capacitance means higher efficiency.
    The problem is finding enough motors and spacing them so that they don’t “latch up”.

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