DV8 2XL

The_most_provoking_post_ever

I stand corrected

Much animal husbandry is based on inbreeding, and yes once the problems have been culled from the germ-line there are no inharent issues with the practice. But...as a consequence the gene pool is reduced in size and the organism is now vulnerable to any outside forces that it cannot adapt to. This has become an issue in cases where an endangered species has been reduced in numbers to the point were inbreeding is common. Any major changes in the environment spell the end.

I wonder if something can be cobbled together using the sensors from the emission control systems from a modern car engine...?

Ok, I finally got the story. This OLD tech, dropped in the 80's.

Here is what I was told by a Health and Safety officer who answered an email I sent several days ago:

- They were used for Class 4 entries, which is a full suit with self-contained air working in a deadly and or explosive atmosphere situation.

- The comm units were integrated into the head gear

-They worked on a low frequency; around 200khz at the center.

-The link was asymmetric: a relatively powerful transmitter and sensitive receiver on the 'outside' end, passive receiver and transmitter on the inside.

-You had to shout your lungs out to drive the passive transmitter.

Apparently they were replaced by low power active comms running on watch batteries, and also entry protocols, and the design of these spaces has changed to the point where solo class 4 entries are rare events.

So I guess that's it

You know most people trying to get us to do their homework for them at least have the grace to say please....or at least not address the group in the imperative.

'年代のＣＱ誌に、ラジオ放送の電波を受信、検波して電源とする製作例がのっていましたが、それとは違います。しかし送信機というからには何らかのエネルギー源が無い事には送信できようはずはありません。種明かしをすると、マイクに向かってしゃべる音声エネルギーを電源に送信するのです。もちろん音声エネルギーの一部は同時に変調にも使用されるので、振幅変調された高周波信号を発生できます。回路図をご覧ください。いろいろなマイクをためしてみましたが、いわゆるスピーカー、それも結構大方のものの方が音声を効率よく電気エネルギーに変換できる事がわかりました、但し、スピーカーのインピーダンスは８Ω'

"This is AM transmitter, using no power supply. It moves only by the voice power. Audio power is translated for electric power and it excite radio frequency oscillator. And by the way, audio power modulates the radio frequency signal. 8cm speaker is used for the microphone."

http://www.intio.or.jp/jf10zl/PLTX.htm

Or the CBC

I was just pointing out that there is a bit more energy available than we have been assuming to this point. The telephones after all are working into a 600 ohm impedance which is almost the equivalent of a dead short by CMOS standards.

Anyway I'm not looking to work skip with these things; 15-20 metres of range would be more than enough for my application.

Correction: The David Clark voice powered telephone sets produce 20 microamps at 60 millivolts on average on a 600 ohm loop. This is actually quite a bit of power if you think in terms of fully integrated CMOS radios ('radio on a chip') type systems.

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.

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.

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

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

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.

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.

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.

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.

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.)

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?

One of my oldest friend's mother has a plastic cheese grater from the 50's. It looks brand new' date=' no scratches, the colors are still vivid. This gadget has been used every week for fifty years and will probably outlive us all.

 

Definitely unobtainium.[/quote']

 

Bet it's made from Melamine (1,3,5-triazine-2,4,6-triamine) a triazine. Anything made from that plastic seems to last forever. Always wanted a car made out of the stuff.

Are the bubbles necessarily separate informationally?

By definition, yes

The bubble universe concept involves creation of universes from the quantum foam of a "parent universe." On very small scales, the foam is frothing due to energy fluctuations. These fluctuations may create tiny bubbles and wormholes. If the energy fluctuation is not very large, a tiny bubble universe may form, experience some expansion like an inflating balloon, and then contract and disappear from existence. However, if the energy fluctuation is greater than a particular critical value, a tiny bubble universe forms from the parent universe, experiences long-term expansion, and allows matter and large-scale galactic structures to form.

The "self-creating" in Andre Linde's self-creating universe theory stems from the concept that each bubble or inflationary universe will sprout other bubble universes, which in turn, sprout more bubble universes.

So it would seen that the only thing that would happen is that a new universe would be 'pinched off' from the old by the forces near the edge of a wall-like attractor.

Have you considered entering the industry in one of the skilled trades and pursuing a maintenance licence? These are well paying positions and have a good deal more job security than engineering. Licences can be written for Airframe, Power (engines), and Avionics (aviation electronics) or in combinations. If you've never thought about that career path, maybe you should,

Correct me if I am wrong, but I think you have to govern the engine against frequency of the A/C output rather than the output voltage. I believe that's the case for most gensets.

One word: Torque.