Been thinkin’. Had an idea. Just gonna lay it out there for discussion.
Currently the only feedback being used is LED lighting. What if you used a tiny piezo crystal instead. Just enough so that you could feel it cklicking? You’d have to have some kind of a charge / discharge circuit. I know it’s a little out there, but maybe??
Tactile feedback has some real advantages. Stealth if you wanna.
Would be interesting if coupled to a 55hz tuned circuit for A/C detection.
Like I said, been thinkin’.
I would like that a whole lot better than magnets too, to feel stuff. Magnets have a number of drawbacks that keep me from experimenting with them - mainly, they lose their strength over time, and they kill magnetic media if you bring them too close. A piezo device would be much better.
I doubt there are small enough such devices though, and mostly I doubt there’s enough power to activate them through induction.
I was thinking harvest a tiny trickle and then store in a capacitor, till you have one click’s worth of juice.
Rinse, lather, repeat.
I agree. They’re usually pretty large, and they’re usually pretty high voltage (by RF energy harvesting standards). Also, I don’t know if high frequency vibrations like that would compromise a spot weld over time.
If you want to give it a shot, though, more power to ya. This is one of the smallest transducers I found (12mm x 12mm)
Maybe not the right type, but I’ll keep looking.
Everything I’m finding is a packaged product though. Could just the raw crystal be mounted between conductors and sealed in by epoxy?
I have… other ideas for tactile feedback… shocking ideas, one might say…
Just make sure you include a voltage limiter 
Well hot damn, I’m intrigued.
it’s the current that kills you… 
basically the most energy efficient way to produce tactile sensation is through electrical stimulation. you can use an extremely small amount of energy to produce a large sensation. That’s why pacemakers can go on for years with a simple battery… the power draw is microwatts at most.
I’d wondered about that originally. My thought was to run a conductor out the tube ends and seal with a little blob of gold.
I just had no clue if you’d even be able to feel it.
there are ceramics that use resins and glass itself to do the sealing, but i had some other ideas - particularly around flex devices.
It’s gotta suck a little having all these cool back burner projects… That you can’t talk too much about because everyone will start clamoring to have them RIGHT NOW!!!
Tell you what would be interesting: an implantable device with an induction coil, a processor to extract nibble or byte data from the carrier, demux the bits and send them to 4 to 8 thin bio-compatible wires of staggered lengths coming out of the device, with naked ends. You would implant it by making a long slice in the skin, and then you’d have a device that “paints” whatever nibble or byte you send to it over the carrier on your skin (or rather, underneath it). That would come as close to a direct nerve input interface as we non-researcher, non-scientist hobbyists could get our hands on.
Hell, I’d settle on an ordinary glass implant with a passive coil and one single bit: with training, I’m sure I could get used to “listening” to morse code over that new input channel, and the transmitter would be trivial to make to boot. I can totally see implanting something like this on the left-hand side of my chest and carrying the transmitter in my shirt pocket. Possibly even get an Android phone to modulate the NFC chip’s carrier directly somehow, so that the phone in my pocket would transmit SMS messages in morse code to the implant, or tell me the time every once in a while or something.
Imagine the possibilities… If you need a guinea pig, I’m your man
See what I mean. 
lilbit
actually the issue is always the interface between conductor and shielding… that is the spot bodily fluids will really badly want to penetrate… I’ve got part of a patent in the works now that addresses our approach… once it’s published i can talk a bit more about it.
Okay, I didn’t know body juices were that aggressive. So presumably any implant with an interruption in the surface material - required to get electrodes out of a device - would have more stringent requirements than a simple glass capsule. Or maybe a glass capsule with a gold lead coming out at each end would not be attacked? After all, glass seals can withstand vacuum in tubes for decades. I suppose they’re not so easily breached.
Damn, now you’ve said too much
Well, when your patent is granted, you can talk at length about it - since the purpose of a patent is to afford legal protection and allow full disclosure at the same time. In the meantime, we’ll just have to be patient I guess…
Are we getting taser fingers in the future?
haha well, i mean, it’s not like acid or anything… mostly it’s just water… water is like… it’s one of the most powerful solvents around and it also just gets everywhere… it’ll find molecular sized holes and seep through… it might take a long time, but it will happen… medical devices like pace makers have special resins and things that they use to seal up these interfaces where probes and electrodes come out, but even those are not rated for more than 10 years… because WATER. WILL. WIN.
Anyway… it’s not impossible or anything, it’s just a pain to deal with sealing things properly… makes manufacturing much more involved… we have have to deal with this issue when applying our polymer… requires a lot of special process to ensure there is absolutely no seam… our polymer encapsulation process produces seamless encapsulation but it took a lot of process design. In fact, we had to get a process controller made (thanks @turbo2ltr !!) just to handle things properly and consistently…
