I want to develop something that detects if it is in the ear or not. It will be in a set of headphones and I want it to be small and use the least amount of...
A capacitive sensor would work fine I suppose, as long as the application is not sensitive to false triggering. Capacitive sensors are sensitive to anything...
If you have a piezo transducer in the ear-plug, it could work as a microphone. You could potentially listen to the heart-beat, and you wouldn’t need to run...
Thanks for the info. I actually never thought of light. That might work even better. I am probobly going to have to go with something that uses 2 wires. 2...
Perhaps conductivity, too. If this device enters the ear canal, contact surfaces on opposite sides of an inserted cone or cylinder should show a relatively...
... You could do this optically with an IR source/sensor pair that detects either the ear penna, shooting across the headphone cup, or the ear surface itself,...
We need a lot more background info to answer this question. Is this transducer coupling to water, metal, or something else? Matching layers are commonly used...
Hi, I have solved this question... Thank you .... I have another one: When we manufacture such devices we put the PZT material in horizantal position and then...
Hi, The answer was as the following : We must centrifuge the matching layer particles before we put it at the top of the PZT material to prevent the air...
Hi all, I was directed to try this forum for info from another, so here goes.. We're redesigning a board that used a Rockwell R68561 communications controller...
I am wanting to make a towed sonar for my rc boat. What is the best sensor around 1/4 inch diameter for underwater use (sealed in a tube, what should the tube...
If this is a home project and will not go more than a few meters deep you may do well with an electret microphone in a rubber bladder of mineral oil. You...
For a GOOD explanation of the piezo effect and how they work, go to your local college library and look into the proceedings of the IRE (Institute of Radio...
I was planning for it to go to 40-60 feet deep. I think the Tygon tube with mineral oil may do it. I'll just have to make one and try it and see how long it...
On the same topic. Here’s a couple of good introductory books on acoustic transducers: Introduction to the Theory and Design of Sonar Transducers Author:...
Hi there, Actually I am not sure I joined the right group, but since I saw many engineering minded people, then I thought this might be a good start for a...
I can help fill in some blanks. GPS satellites are in geosynchronous orbit. They don't move they are rotating around at the same speed as the earth turns...
... rotating around at the same speed as the earth turns (about 75% sure on this may be wrong) Jonathan, you're slightly off on this one. The radius of the...
... The GPS satellite doesn't have a limit for the number of users that it can serve. The GPS satellite only transmits, it doesn't receive. One of the...
... The nominal number of the satellites (SVs) is 24. Currently, we have 28. The additional 4 are spares. Since the satellites don't age from transmitting...
Hi, Honestly, I don't know the answer for those questions, but I feel curious to know ! I think that the questions were very interested... Waiting to have the...
... wrote: Jonothan, Thank you very much! Very helpful. ... rotating around at the same speed as the earth turns (about 75% sure on this may be wrong) ... ...
Nick, Thank you! ... I read the definition of geosynchronous orbit it is an orbit around the Earth with an orbital period matching the Earth's sidereal...
... I read yesterday on Yahoo that the Russian rocket, because of the problem with one of its engines, couldn't deliver the American satellite to the correct...
... Nick, Thank you! What is "SV" stands for Soviet? (LOL) What is the significance of the number 24? Do 12 of them are circling Northern hemisphere and 12 ...
... 12 ... least ... SV stands for Satellite Vehicle. My guess is that this term could go back to the very early stages of the GPS project, when other ...
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