Sensor CA-YD-185 for soundboard testing

Sensor CA-YD-185 for soundboard testing

Postby Josephus » Fri Nov 23, 2018 7:57 am

Can that probe (sensor CA-YD-185) be used with an adapter to a microphone input on a computer sound-card with an external power supply?

Would the multi-meter or data logger display the data.

Would it be appropriate to use for measuring soundboard movements: acceleration, velocity, displacement in real time on a guitar top for example.

If so can a demonstration be done and posted on this forum or a video made as you did for the speed of sound?

Thank you. Joseph
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Re: Sensor CA-YD-185 for soundboard testing

Postby VirtinsTech » Sun Nov 25, 2018 4:14 am

CA-YD-185 is an IEPE accelerometer. It requires a 24V 4mA excitation power supply as shown below. You can use an external 24V 4mA constant current power supply to drive an IEPE sensor, and feed its output to an AC coupled data acquisition system such as a sound card or a VT USB DSO. You can also use our product VT IEPE-2G05 which already has built-in 24V 4mA power supplies to excite the IEPE sensors.

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IEPE sensors come with a factory-calibrated unit-specific sensor sensitivity. For example, an IEPE accelerometer may have a sensor sensitivity of 50 mV/g. If the data acquisition system is already voltage calibrated, such as a VT USB DSO or VT IEPE-2G05, then the acquired data can be converted from absolute voltage to absolute acceleration by software. Absolute velocity and displacement can then be derived through integration. Unfortunately, a sound card is usually not voltage calibrated, therefore, it can only perform relative amplitude measurement unless the users calibrate the absolute voltage by themselves. Depending on the output voltage of the IEPE sensor during measurement, either mic input or line input of a sound card can be used.

Some sound cards have XLR mic inputs with built-in 48V phantom power supplies. On the 48V pin, there is an internal current limiting resistor in series which would limit the current to be less than 20mA even if it is shorted to GND. If the IEPE sensor is able to withstand 48V, then an easy and workable solution (admittedly not very professional) is available as follows. In this way, the external 24V 4mA constant current power supply is not needed.

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In addition to the electrical interface compatibility, the following parameters need to be considered when judging whether CA-YD-185 is suitable for measuring soundboard movement:

1. Frequency Measurement Range of the sensor
2. Size and weight of the sensor
3. Mounting methods (adhesive, stud, screw, magnetic)

If the sound board to be measured is big and heavy and you have a good way to mount it, CA-YD-185 is probably OK. Otherwise, CA-YD-160 would be better, as it is much lighter and smaller. It can be mounted using adhesive.

In case CA-YD-160 is still too heavy and too big, then piezo film sensors can be considered.
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Re: Sensor CA-YD-185 for soundboard testing

Postby Josephus » Tue Nov 27, 2018 4:22 am

Thank you for your detailed answers. I will study them including the options your suggested re: piezo film sensors and CA-YD-160 and how to use them during a manufacturing process.
Much appreciated.
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