transducerultrasound
I would like to know what is the current consumed by a 1-2MHz Ultrasonic Sensor (i.e sensors used for Clamp on Ultrasonic flowmeter) to generate Ultrasound waves. The two ultrasonic sensor specifications I've found (see below), do not mention the current current consumed, why is it ? when I've enquired with one supplier I've found that they were not sure either.
Sensor Specification 1:
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Sensor Specification 2:
Edited Title of my question
Try these linear amplifiers made by Apex. They are designed specifically for ultrasound aplications.
The problem with hobby related solutions is documentation is limited and not spec'd like commercial components or modules.
It is possible that it may work but make a block wiring diagram and consult with the OEM is advised. Mind you I don't know if they have adequate support for your question as these are built in China.
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It appears that your ultrasonic load is TTL so there is no problem switching 5 at the same time with a BEC, but I wonder if you have considered the effects of crosstalk on firing all at the same time. They indicate a 15deg detection angle but this would depend on the reflection angle of objects you wish to detect. There may be phasing issues with reflection cancellations like having 5 tweeters directed in a room. Reading the response of each echo in parallel with a time interval count won't be a simple textbook result with non-smooth objects with 5 senders.
YOu can test your orthogonal array design with any signal pulse generator and look at the signal on a parallel port logic analyzer or scope to ensure what you are design will work.
Power drive is the least of your concerns from these low power devices. Noise avoidance from conducted and radiated sources will be paramount and design of the transponder array must come first. I would spend some time on testing this part 1st to identify all the electrical, physical, acoustic, EMI, thermal, vibration both conducted and radiated sources of interference and how each affects your SONAR expectations with different objects. Will it be microphonic with vibration or loud pulse noises. How well does it reject other ultrasound sources of noise? Will the TTL Echo output change in pulse width with signal strength or just the delay time.
Will you get echos from the wrong sender due to corner refection effects.
Best Answer
These are bare piezoelectric elements so they can be used as transmitters and/or receivers. There is no impedance specified for the first sensor although the nominal driving voltage is specified as 1-10 V peak-to-peak. At the resonant frequency, I would expect the impedance to be on the order of 100 ohms. In that case, the driving current would be in the range of 10 to 100 ma peak-to-peak. Unfortunately, for a better value you would have to actual drive the sensor and measure the current or measure the impedance at the resonant frequency. For the second sensor, the capacitance is specified as 1800 pf and the parallel impedance as 60 ohms. The static capacitance is the value of the intrinsic capacitance due to its being made of ceramic. The parallel impedance is the impedance due to the resonance of the element. 1800 pf at 2 MHz has a reactance of 44 ohms. You can use the parallel combination of this with the 60 ohms to get a reasonable estimate of the overall impedance at resonance. Then the current can be calculated with ohms law. However, again, measuring the current on an actual sensor is the most accurate method.