# How to measure and verify ultrasound frequency and intensity from a cheap ultrasonic body contouring device?

Research shows that applying 1 MHz non-focused ultrasound at 3 W/cm2 may reduce subcutaneous fat thickness. In fact, high-end and expensive (costs $5000 >) HIFU ultrasonic transducers are now being used in cosmetic clinics that allow the user to regulate ultrasound frequency, pulsing, power and time in order to target body fat. To my surprise, I noticed that one can also buy inexpensive (costs only$50), portable 1Mhz Ultrasound cavitation device from Ebay or Aliexpress that also claims to reduce body fat. Scam or not, one way to justify its claim will be to measure and verify the emitting frequency and intensity.

I bought such a device from Aliexpress (costed \$130) to play around with it. My skin can feel a definite vibration when I turn on the device, however, it is very hard to tell if ultrasound is actually exciting my tissue lesions.

I want to know how to set up an inexpensive testing setup and:

1) Find out if the device is really emitting ultrasound. If yes, how would I measure its frequency? Device manual says 1MHz, but I suspecting it might be a bs.

2) How to measure the intensity and penetration depth. Finding one value should lead me to calculate another.

3) Find out if the device's ultrasound is focused or non-focused. My gut feeling is the ultrasound is non-focused or weakly focused.

One way to find more clues would be to rip through the device and look at the transducer circuit. The transducer hardware might have a model number that can be used to find it's spec sheet online. However, I haven't unscrewed the device yet and I doubt I would find anything helpful on the circuit board as it probably came directly from a questionable Chinese factory.

Further reading: There has been plenty of research conducted so far regarding effects of non-focused ultrasound on animal contouring:

• Use it for 3 weeks and see how your weight / fat changes... if it does not change then either you were had, or something else needs to change... – Solar Mike Nov 20 '18 at 8:59
• @SolarMike Unfortunately that's not a very conclusive test, because if the OP starts using a device like this to reduce fat he/she will most likely change his/her eating habits at the same time, and would have lost the fat even without the device! – alephzero Nov 20 '18 at 10:26
• @alephzero holding all the other variables constant and only changing one is, of course, the challenge! – Solar Mike Nov 20 '18 at 11:08

## 2 Answers

You can measure this with a piezoelectric transducer and an oscilliscope. Several companies sell thin film piezo transducers that you can just stick onto your device under test. The transducer has leads that you would connect to a piezo pre-amplifier which will amplify and buffer the signal coming from your DUT. Then attach a scope lead to the output of the pre-amp and you can see the signal on your scope.

If you have access to the right hardware with a sampling rate higher than the frequency of the transmitter, you could record the audio signal and do a fast fourier transformation on it. That will give you the amplitude and frequency of the most prominent waves in the signal.