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PGA460-Q1: Range

Peter Kovacic
Prodigy 60 points
Part Number: PGA460-Q1
Other Parts Discussed in Thread: PGA460PSM-EVM, BOOSTXL-PGA460, MSP-EXP430F5529LP, , PGA460

Hello,

I bought a PGA460PSM-EVM evaluation board for testing.
I would like to ask you to answer a few questions.
1. Is it possible to connect the evaluation board PGA460PSM-EVM directly to a PC with SW support PGA460-Q1 EVM without the use of additional demonstration kits (BOOSTXL-PGA460 and MSP-EXP430F5529LP)?
2. Is it possible to use the sensor for measuring stationary or slow-moving objects in the range of 4cm to 60cm (max. 100cm)?
3. Which components need to be replaced for this range (Ultrasonic Sensor - Transceiver, Transformer, ...)? Can you recommend any?
4. Is the ultrasonic transducer MCUSD13A300B09RS suitable (uk.farnell.com/.../2362690)
5. Which register sensors should be changed?

Thank you, Peter.

  • 0
    TI__Expert 7599 points

    Hi Peter,

    Here are our response.

    1) You will have to connect the PGA460PSM-EVM to one of the demo kits if you like to evaluate using our PGA460 software. The other option would be to tie the PGA460PSM to your preferred microcontroller and complete the evaluation. For this you will have to refer to our datasheet of the PGA460-Q1 to learn about the protocol that can assist in your software development 

    2) 60 cm is not an issue with the PGA460. 4cm measurement remains a challenge unless you configure the PGA460 in bistatic mode. 

    3) PGA460 can be configured in direct drive mode which can enable measurements up to 60cm. The datasheet application curves do have graphs that demonstrates the direct drive capability to drive transducers without the transformer up to 100 cm with a peak to peak voltage of 7.2V. This will eliminate the need for external transformers. 

    4) The transducer datasheet link is broken. Doing a quick search it turned out that this transducer is a 300 Khz. PGA460 can support 300 Khz. Its unclear if the 300 Khz can detect 1m. The datasheet here has a graph of driving the transducer at 200v pp to measure an object 20 cm. You will have to try this out using our EVM to see if the direct drive mode can support the range.  

    5) The configuration depends on the choice of transducers, drive voltage, drive frequency, receive signal gain, interface etc. For more guidance you can look at our PGA460 FAQ PGA460PSM-EVM users guide for steps and guidance on configuration. 

  • 0 in reply to Arjun_Prakash
    Prodigy 60 points

    Hi Arjun,

    Thank you for your answers.
    Could you recommend a sensor for measuring distances from 4cm (or 5cm)?

  • 0 in reply to Peter Kovacic
    TI__Expert 7599 points

    Hi Peter,

    Let me look at this and get back in a couple of days. Also, can you help me understand if you need a close top or an open top transducer ? This depends on the application if the sensor will be exposed to external world like humidity and dirt. 

  • 0 in reply to Arjun_Prakash
    Prodigy 60 points

    Hi,

    The transducer must be closed. The application is for outdoor use.

    Thank you, Peter.

  • 0 in reply to Peter Kovacic
    TI__Mastermind 27950 points

    Hi Peter,

    Here are my recommendations for your high-frequency PGA460 evaluation:

    Pair your PGA460PSM-EVM module with the MSP-EXP430F5529LP. This will enable you to use the GUI in UART mode to help you optimize and configure the device settings. The GUI helps to plot and visualize the echo envelope, time varying threshold, and time varying gain mapping, which you will be spending most of your time optimizing. This EVM-GUI video series will help guide you through the optimization process: Ultrasonic Sensing with the PGA460-Q1 (6 videos)

    The PGA460PSM-EVM as-is will support low frequency transducers (30-80kHz). To make the PGA460PSM-EVM compatible with your 300kHz MCUSD13A300B09RS transducer, you will need to make the following modifications:

    1. Replace the transformer with a high-frequency compatible transformer. You can find some pin-to-pin compatible high frequency transformer examples available here: PGA460 Transducer & Transformer Listing
    2. Remove the capacitor and resistor that are in parallel to the transducer. These matching components are optimized for the specific 40kHz transformer-transducer pair on the default PGA460PSM-EVM. Most high-frequency transducer-transformer combinations do not require matching components. so you can leave this DNP for now. Adding a damping resistor later may help achieve improved minimum / short range detection (if necessary).
    3. Remove the 40kHz transducer, and install your 300kHz transducer (be sure to make note of the polarity during install).

    In my experience, most 300kHz transducer in a mono-static (single transducer to transmit and receive) transformer driver mode are able to achieve downwards of 4~5cm minimum detectable range. The maximum range tends vary more so from part number to part number, but 1m is feasible.