BOOSTXL-TUSS4440: Distance measurement tests with a 300kHz piezo.

Manon Alluard

Part Number: BOOSTXL-TUSS4440
Other Parts Discussed in Thread: TUSS4440

Hello,

I want to measure distances between 5cm and 60cm. To do this, I am using a 300kHz piezo (CUSA-TR07-01-400-TH67), which, according to the datasheet, is ideal because this sensor has a detectable range included between 5cm and 1m.

I did some tests using the BOOSTXL-TUSS4440, the 300kHz piezo and the GUI software. Various distances were measured, as shown in the images, with the bellowing configuration:

Frequency = 301.28kHz

Burst number = 16

Current XFMR_DRV_ILIM = 100mA

VDRV_CURRENT_LEVEL = 5V

According to the TUSS4440 datasheet (p35), for 400kHz, at 5V, the amplitude of the echo goes from 1.8V (0.3ms) to 0.8V (1.7ms), while in my tests the amplitude is only at 1.2V (0.4ms) to 0.6V (1.8ms).

Why the results obtained with the 300kHz piezo are not as good as those with the 400kHz (from the datasheet)?

Regarding our use case (5cm to 60cm), which frequency suits the most?

Thank you for your answer.

Manon.

6 months ago

0 Alicia Rosenberger 6 months ago

TI__Expert 8410 points

Hi Manon,
Thank you for posting to the Sensors forum!
What is the target that you are using? There could be many reasons that you are seeing the results that you are, one of which could be the target that you are measuring.
Best,

~Alicia

0 Manon Alluard 5 months ago in reply to Alicia Rosenberger

Prodigy 10 points

Hello,

For now, I am testing the sensor using a wall (solid surface) as a target. I did the same tests with a 200kHz piezo, on the same target and results were good. So, I don't think the issue comes from the target.

Do you have another explanation ?

Best,

Manon.

0 Alicia Rosenberger 5 months ago in reply to Manon Alluard

TI__Expert 8410 points

Hi Manon,

Yes, transducers are built different and even though they may operate at the same excitation frequency the may respond differently to stimulus and echo reflections. Hence why its important to test each transducer with your system to ensure you are getting the performance you are expecting along with the device.

Best,

~Alicia

0 Manon Alluard 5 months ago in reply to Alicia Rosenberger

Prodigy 10 points

Hello,

Do you have a reference for a piezo to measure between 5cm and 60cm ? Else, could you specify the characteristic to look for when buying a piezo ?

Thank you,

Manon

0 Alicia Rosenberger 5 months ago in reply to Manon Alluard

TI__Expert 8410 points

Hi Manon,

Based on the current information given, it sounds like the 200kHz piezo seems to be working fine for you. Is there something preventing you from using it? Or is it not giving you the full range needed?

Best,

~Alicia

0 Manon Alluard 5 months ago in reply to Alicia Rosenberger

Prodigy 10 points

Hello,

The 200kHz piezo can only measure 10cm, not 5cm, that is why it doesn't reach all my needs.

However, the 300kHz should be working for my use case, but the one I have (CUSA-TR07-01-400-TH67) doesn't work well. Do you have another reference for a 300kHz ?

Thank you,

Manon

0 Alicia Rosenberger 5 months ago in reply to Manon Alluard

TI__Expert 8410 points

Hi Manon,

I will need to discuss this with my team and will aim to provide a response by the end of the week.

Best,

~Alicia

0 Manon Alluard 5 months ago in reply to Alicia Rosenberger

Prodigy 10 points

Hello,

Thank you, I am waiting for your response.

Best,

Manon.

0 Alicia Rosenberger 5 months ago in reply to Manon Alluard

TI__Expert 8410 points

Hello Manon,

We have tried a couple of different transducers I am not sure if any of these will meet the requirements but feel free to test these out. The list can be downloaded here: https://www.ti.com/lit/zip/slac787

You could also use a tuning capacitor and damping resistor to try and tune the decay time of your 200kHz transducer to meet your 5cm requirement.

We have some more info in this app note if you would like to look into this some more: https://www.ti.com/lit/an/slaa732a/slaa732a.pdf

Best,

~Alicia