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TDC1000-C2000EVM: does TDC1000-C2000EVM fit to measure distance from water (in air) 2cm - 150cm ?

Part Number: TDC1000-C2000EVM
Other Parts Discussed in Thread: TDC1000, , TUSS4470, PGA460, TUSS4440, BOOSTXL-PGA460

We are currently using an off the shelf, ultrasonic sensor to measure the distance from water (in air) of a Hydrofoil vessel (MassaSonic FlatPack 160 that uses bistatic transducer topology at 160KHz )

the sensor gives us reasonable results, but is not flexible enough and very expensive.

our requirements :

2 cm - 150 cm detection range

high reliability and robustness to environmental conditions

Does TDC1000 fit for this purpose?

if so does  TDC1000-C2000EVM will fit for quick proof of concept evaluation

if not do you have other suggested solution? 

Thanks,

Assaf Friedman

CTO  

  • Assaf,

    For air coupled measurements, I recommend that you consider using the PGA460, TUSS4470, or TUSS4440 devices instead of the TDC1000, which is more suitable for liquid coupled applications.

    Considering your minimum range is down to 2cm, you will need to use a high-frequency ultrasonic transducer (180-450kHz). For a full list of high-frequency transducer part numbers, see the PGA460 Transducer & Transformer Listing spreadsheet.

    Also, you will need to consider if you want to use a transformer driver or a full-bridge driver to excite the transducer. I recommend using a transformer driver for best case results in both minimum and maximum ranges, but a half- or full-bridge driver may also work if you need a smaller/cheaper solution.

    The BOOSTXL-PGA460 EVM is my recommended starting point for high-frequency transducer evaluation. Note, the transformer provided with this EVM is compatible with low-frequency transducers (up to 80kHz for 15cm minimum), so you will need to replace the transformer with a high-frequency compatible transformer (options also listed in the spreadsheet linked above).

    There are several feasible options for your given range, so if you find a favorable transducer based on price/availability, I may be able to provide some additional insight into its performance before you order it.

  • Hello Akeem,

    Thank you for your detailed response, I have already ordered the  BOOSTXL-PGA460 and plan to test it.

    I will use bi-static configuration to get the best short distance results possible, I could not find much documentation for this type of configuration so if you have a good reference or tips it might help.

     I also need a wide beam angle so many of the higher frequency transducers does not fit ,I checked at length the PGA460 Transducer & Transformer Listing  for availability and prices and could not find a fit, I will test few chines brands 200kHz transducers. I will also check some 58Khz transducers (the Murata that you supply is not available)  and check for short range performance with bi-static configuration. do you have recommendation regarding the transformers to use? the TDK-EPCOS B78416A2386A003 or the wurth elektonik  750316928?

    Best regards,

    Assaf

  • Assaf,

    My recommendation for your bi-static evaluation is to treat the configuration just as you would a mono-static solution. The biggest difference is that you can keep the initial time varying gain level much lower in a bi-static solution to prevent the scaling of a false-echo-positive created by the internal switching noise of the driver stage. This will keep your receiver path relatively flat (at noise level). This will make more sense as you begin to evaluate the BOOSTXL-PGA460.

    The BOOSTXL-PGA460 EVM user's guide ( http://www.ti.com/lit/pdf/slau659 ) contains instructions on how to configure the EVM for bi-static operation, as well as PGA460 FAQ #4.4.6 ( http://www.ti.com/lit/an/slaa733/slaa733.pdf ).

    You can see example results of a bi-static solution in the Ultrasonic Floor-Type and Cliff Detection on Automated Vacuum Robots tech note: http://www.ti.com/lit/an/slaa909/slaa909.pdf 

    The TDK-EPCOS B78416A2386A003 and Wurth Elektonik 750316928 yield nearly identical results based on our testing, so the choice is based on your preferred part availability, size, and cost.

  • Hello Akeem,

    We are evaluating the PGA460 now.

    I will change the transformer to TDK-EPCOS B78416A2386A003  and will evaluate different ~200khz transducers.

    How critical it is to change the tuning capacitor and resistor in the daughter card, considering the fact that we are using a bi-static configuration.

     

    Thanks,

    Assaf

  • Assaf,

    When using your 200kHz sensor configuration, it is important that you do not use the same matching components (tuning capacitor and damping resistor) that were installed for the 58kHz Murata transducer. The installation of new matching component values is not necessary, but could improve performance. In many cases of high frequency transducer evaluation, the matching components do not always have an impact. If you are able to meet your system requirements without matching components, you're in luck.