what are the principles of a ultrasonice based sensor?
346351
If you throw say your car keys on the kitchen table they will jangle making audible sounds you can hear and ultrasonic sounds with frequencies too high for you to hear.  An ultrasonic listening device can "hear" the sounds you can't hear.  For example truck drivers may point an ultrasonic test device at their tires to hears air leaks that humans can not hear.  The pickup is like a sensative small microphone.  Perhaps you can use a search engine to find "ultrasonic tester" etc.  Good luck.
213935
good website is www.howstuffworks.com.  See:  http://electronics.howstuffworks.com/ultrasound1.htm
31879
Passive sonar systems are used primarily to detect noise from marine objects, such as submarines, ships, and marine animals like whales. Unlike active sonar, passive sonar does not emit its own signal, which is an advantage for military vessels that do not want to be found or for scientific missions that concentrate on “listening” to the ocean. Rather, it only detects sound waves coming towards it. Thus, passive sonar cannot measure the range of an object unless it is used in conjunction with other passive listening devices. Multiple passive sonar devices may allow for triangulation of the sound source. (Read more on passive ocean acoustic monitoring.)
140778
Oxygen Sensor - an electronic device that measures the proportion of oxygen in the gas.
596509
1) Flat and hard surface. By flat I mean the microtexture, so the sound doesn't get scattered, convex like a parabole is possible if the sound originates from the center of the parabole.\n2) There has to be a large distance between wall and origin for accurate meassurement. Or you would need very fast measurementdevices.\n3) Since sound is carried by a medium the speed of that medium has to be taken into account. If you measure both ways then the speed of the medium, assuming that it didn't change directions, on one measurement has an negative effect and on the otherone an equal positive effect. By taking the average this is levelled out.\nEach measurement involves two reaction times; the reactiontime to the lightflash and the reactiontime to the sound. If both are equal, the measurement would be exact. Assuming that there is no significant difference for the reaction to sound and the one to light the error made by difference in both reactiontimes can be both ways. So by increasing the number of measurements and taking the average you increase the accuratesse of your measurement. If the error in measurement due to reactiontimes would allways be one way (allways to high or allways to low soundspeed) then taking the average would have a negative effect on the accuratesse, because the measurement with the smallest error would allways be the most accurate.
228013
Do a web search for the parameters.  We would need much more information from you on sample types, volumes, etc and you capabilities, instrumentation available, etc.  All of these are factors in deciding a method.
149739
"A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, position and pressure sensors, and antenna. Although not generally thought of as transducers, photocells, LEDs (light-emitting diodes), and even common light bulbs are transducers."
77413
make any sensing devices, which has the altest features. u can get a lot abt them on internet and modify them for the latest demands
168920
This is ultrasonic, not electromagnetic, so C is irrelevant.  The equation is:\nF=V/L where V=sound velocity in water (~1475 m/s), F=frequency in Hz, L=wavelength (0.0003 m)\nResult is you need 4.9 MHz or higher.
911903
Well, you could build a *relatively* simple circuit that simply cut the frequency in half, but then again, what kind of sensor are you dealing with?\n\nWhy do you want to tune it to a lower frequency? It is not simple to just shift a frequency, there are many things to take into account; input impedance, output impedance (both may be frequency dependent), signal amplitude, and required voltage swing.\nI would only attempt this if it was not a vital sensor I was messing with.
554109
use ultrasonic machine... the sound waves should shatter it to smithereens
1134878
They're essentially the same.  \n\nIf there is a small difference it is that the sensor is the device that converts a physical quantity to another (usually electric, like a microphone convert sound to voltage).  The transducer might be a device that contains a sensor and further converts the electricity to a more useful and interpretable value (e.g. a microphone might produce a tiny voltage and there may be an amplifier to make it a larger signal, making it less sensitive to noise and so forth).\n\nANyway, I hear the two used interchangeably all the time.
696385
SONAR (SOund Navigation And Ranging), is based on the principal that sound propagation through a liquid-based medium is reflected off of objects it hits, and when directed towards the ocean floor, it can be reflected off the bottom, shipwrecks, cracks, coral reifs, or even large fish.\n\nWhen you create a time-based map of the data, you can create a topographic relief of the ocean floor.\n\nPlease see: http://en.wikipedia.org/wiki/Sonar for more information.
62361
Try it. CAUTION - KEEP LIQUIDS AWAY FROM ELECTRICAL CURRENT.\n\nSet up a loudspeaker next to a glass of water (a wine glass is good for this)\n\nWhat do you think will happen when you alter the sound from the speaker?\n\nInvestigate and observe.\nTry a thicker liquid such as milk.
841020
ever heard of ultra sound.  It can be used.  But the frequencies and power needed to produce results in some things would actually cause damage to surrounding tissue.
556687
2) Use stop wave:\nPlace a speaker of known, variable frequency close to a micro, the micro is connected to a microamperemeter.\nPlace that in the top of a long glass tube, slowly fill the tube with water until the the microamperemeter show a maximum. Continue filling the tube with water to get the next maximum. The distance between the two consecutive maximums is half the wavelength.\nSpeed = wavelength x frequency.\nRepeat the experiment several times and get the averange. That should be close to actual value.
203035
The sound is measured in decibels. There should be a tag inside the smoke detector with that information.