DV8 2XL Posted April 11, 2006 Share Posted April 11, 2006 These devices apparently exist as a quick Google search will reveal. However I can find nothing definitive on the matter, and I've racked my brain for search terms. I would like to get my hands on something like this, but I'm drawing blank stares. Has anyone here come across these in their travels? Link to comment Share on other sites More sharing options...
Externet Posted April 11, 2006 Share Posted April 11, 2006 Hi. ¿Was it April first? Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 11, 2006 Author Share Posted April 11, 2006 No, in fact as I recall one could build a primitive (but working) example of one with the old Radio Shack 150 and 1 breadboard sets and I could probably cobble something like that up too, but I am looking for a 'pro' model (as it were.) Link to comment Share on other sites More sharing options...
ecoli Posted April 11, 2006 Share Posted April 11, 2006 The only thing I found on this using google was some articles from the 50's describing how such technology might work... are you sure about this? Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 11, 2006 Author Share Posted April 11, 2006 No I'm not. I was hoping someone else knew something about these. I've seen them referenced for restricted entry work (going into tanks and and utilidors and such) and some oblique military references as well. I'm assuming they aren't referring to some VOX-type of system...but I may be wrong. Link to comment Share on other sites More sharing options...
5614 Posted April 11, 2006 Share Posted April 11, 2006 Where did you hear or read about em? [edit] sorry, answered above, the post wasn't there when I started typing, a mod can delete this post if they wish. Link to comment Share on other sites More sharing options...
ydoaPs Posted April 11, 2006 Share Posted April 11, 2006 i've seen people power xmas lights with sound, but not radios. why would you want to, anyway? if you did, the ambient noise would always be louder than the radio. edit: unless you are talking about transmitting. you'd still have to be pretty loud to get a good signal. Link to comment Share on other sites More sharing options...
RichF Posted April 11, 2006 Share Posted April 11, 2006 No, in fact as I recall one could build a primitive (but working) example of one with the old Radio Shack 150 and 1 breadboard sets and I could probably cobble something like that up too, but I am looking for a 'pro' model (as it were.) I was speaking with an older neighbor of my grandmothers, in his eighties, about a month ago and I asked him if that was a telegraph up on his shelf. He said no and started to explain to me that it was a Crystal Radio. It had primitive headphones and a copper switch that you moved back and forth to change channels. Maybe this is something similar? Here's info on how to build one... http://sci-toys.com/scitoys/scitoys/radio/ten_minute_radio.html Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 when you say "Voice Powered radio" you must mean a Receiver unit, as a transmit unit wouldn`t be any good past a few feet at best. assuming the Former, then it`ll be akin to a Crystal set. these require no Power beyond the RF signal it receives, basicly a Diode rectifies the AC radio signal effectively peeling off the carrier and leaving the Difference (the audio) that gets presented to high impedance headphones. the diode (often germanium) need not be factory made, you can use a peice of Coke and a needle or a pencil lead and a razor blade, both work well. Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 I've build a few xtal sets in my time too, but no I'm definitely looking for a transmitter. The reason you would use one is that RF can get through where sound cannot, and in the case of a tank entry or natural gas culvert, explosion proof equipment needs to be used. Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 well the only other possible Stretches of the "Voice powered" definition might mean Voice/Sound activated, Or SSB perhaps? however IF it were to use the actual Mic itself (it would have to be a specialy wound/matched sort) and the right transistor, it`s perfectly conceivable that such a device could be made to work, although I don`t think you`de get very far with off-the-shelf components, you`de also need a pretty good receiver too, but yeah, it would possible in my estimation edit: any idea what freq it worked on? Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 The one I built from the Radio Shack set worked at BCB (550-1750Khz) and ya it was only good for about 3 metres. But - say someone is working in a sewer under a road, and wants to communicate with another standing above - well then 3 metres would be fine. Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 yeah, I can`t imagine that off-the-shelf parts would give you much more than that, although the parts in such kits are pretty generic you could probably extend this range quite a bit further if you were selective with your components,,, say 50 metres (with a good receiver). it`s certainly not a Difficult circuit to make, and it Would be possible with todays stuff to even make a diode charge pump for a more Even output on quieter sounds! Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 Here's something I ran across whilst searching; not exactly what I had in mind but interesting none the less: Abstract. Enabling technologies for wireless sensor networks have gained considerable attention in research communities over the past few years. It is highly desirable, even necessary in certain situations, for wireless sensor nodes to be self-powered. With this goal in mind, a vibration based piezoelectric generator has been developed as an enabling technology for wireless sensor networks. The focus of this paper is to discuss the modeling, design, and optimization of a piezoelectric generator based on a two-layer bending element. An analytical model of the generator has been developed and validated. In addition to providing intuitive design insight, the model has been used as the basis for design optimization. Designs of 1 cm3 in size generated using the model have demonstrated a power output of 375 µW from a vibration source of 2.5 m s-2 at 120 Hz. Furthermore, a 1 cm3 generator has been used to power a custom designed 1.9 GHz radio transmitter from the same vibration source. Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 Hmmm... possibly modulating a tunnel diode? just a thought Link to comment Share on other sites More sharing options...
Externet Posted April 12, 2006 Share Posted April 12, 2006 Hello. The nearest related technology I know of about your question is not that new, from an article in the seventies. An U.S. embassy in Moscow received a present from the russian government, a nice piece of folklore art or something like that and ended hanging on the wall of the ambassador's office after exhaustive inspection from security to avoid spyonage bugs. Well, they found much later the thing had a few millimetres long and innocent metal wire in something like a resonating cavity (think of a microguitar). That was it. A microwave beam was aimed to the thing from a nearby building, and the voices and conversations in that office modulated the wire tuned to the incoming beam, re-radiating or bouncing the signal picked by a receiver in another nearby bulding. Isn't that clever? Entirely passive! A piezoelectric transducer, to charge a capacitor with collected energy from noises could emit very brief bursts of data on micropower transmission to a limited distance, if a very engineered device is built. But the energy is way too small, unless your piezoelectric wafer is truly large and exposed to large noise, leakless capacitors for storage, etc... I don't see voice as capable of. An alternate power source may be the 50/60Hz radiation around us, collected and rectified by some sort of 'crystal radio' tuned to mains frequency. It is an interesting subject, keep stirring the idea, some will come out of it. Miguel Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 anything "tuned to the mains frequency" would require an antenna of massive length, think 300,000 /50 and that`s the length of a full wave antenna in METRES! even a 1/4 wave ant would be phenomenaly long. and that`s just to pick up the RF for conversion, so unless you had a coil up-close and personal to another 24/7 device mains powered, it`s impractical. Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 Here's something else parenthetically on the same subject I found while hunting for my device: "The Wireless, Battery-less Light Switch. "EnOcean, a Siemens spin-off, is developing a fully wireless light (or any other device) switch, no batteries required. Using a piezoelectric generator, the act of pushing the switch generates just enough electricity to transmit its unique switch code. Claimed range of the switch comes in at around 300 meters, which should give end-users plenty of flexibility." From: http://www.enocean.com/indexe.html Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 well all ya gotta do is think of the Very Old blast boxes (as shown on Roadrunner cartoons) to know that a toothed shaft and cog with a little low gearing inside to a dynamo works similar principal I expect. Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 well all ya gotta do is think of the Very Old blast boxes (as shown on Roadrunner cartoons) to know that a toothed shaft and cog with a little low gearing inside to a dynamo works similar principal I expect. Well if you really want to see something that does just that' date=' check out this little rig: http://www.onjapan.net/2001/hamfair/qrp.html Link to comment Share on other sites More sharing options...
YT2095 Posted April 12, 2006 Share Posted April 12, 2006 well sweet! ) I`ve operated 10 metres on a hand generator (didn`t even try DXing though) but I got 4 miles with a 30+ Q5 report to another station in Walsall during mid day! Link to comment Share on other sites More sharing options...
Externet Posted April 12, 2006 Share Posted April 12, 2006 Hi. A long antenna is not really necessary, as a pocket radio with a few turns coil on a ferrite rod and a few picofarads tunes to AM. A tuned circuit of a few microfarads and a coil on iron core can extract some tiny energy from mains radiation; of course a long antenna would improve it. Miguel Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 12, 2006 Author Share Posted April 12, 2006 Hi Miguel - Yes there are a lot of methods of harvesting low grade ambient energy to charge a super cap and then use the stored power to drive a transmitter. However that's not really what I have in mind; I am looking for a particular device that converts the human voice into RF. As I said up thread, there is passing mention of such a device here and there and some homebrew examples. I would very much like to put my hands on some commercial models. Link to comment Share on other sites More sharing options...
Externet Posted April 12, 2006 Share Posted April 12, 2006 Hello Am not familiar with such item being available on commercial scale, but will make a couple of phone calls and will find out some more. It is all about energy. I read somewhere that a person yelling non stop for cannot remember how many years, would produce the energy to warm a cup of coffe. Dealing with such extreme does not make it simple. Besides, the range obtainable in real time electrical transmission would be near nothing, surpassed in range by far by the plain voice range itself. A piezoelectric flame lighter strikes a crystal and creates a respectable high voltage at a minute current and for a brief moment, but the strike is considerable respect to voice induced vibration. Get a piezoelectric transducer out of a defunct telephone ringer -or many!- (the larger diameter the better) and connect it to an oscilloscope to measure its voltage, then load it with some resistance to simulate either charging a capacitor (diode rectification of course in circuit) or operating a circuit. I do not think it has to be much more efficient than talking in front of a loudspeaker and measuring its output as a microphone. I say piezoelectric because has a remote chance of surpassing the 0,2V of a Ge rectifier. Storing that energy for brief, very brief transmissions is doable, but in real time, cannot see it. Not much more I can think at the moment Miguel Link to comment Share on other sites More sharing options...
DV8 2XL Posted April 13, 2006 Author Share Posted April 13, 2006 Voice powered telephone equipment has been around for a long time. I checked a data sheet on one currently marketed unit and found that the average output is 40mV delivering 2 microamps, to me this is more than enough juice for a high impedance load. Also this technology is mentioned in OSHA's Confined Spaces Standard, hardly an organization given to daydreaming. Link to comment Share on other sites More sharing options...
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