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PGA460: Horn design for muRata transducer

Kevin Abishek
Prodigy 160 points
Part Number: PGA460
Other Parts Discussed in Thread: , ENERGIA

I need dimensions for a horn design for the open top transformer driven transducer that comes attached to the BOOSTXL-PGA460 EVM daughter card. 

My sensing range falls between 3m to 5m. Is it fine to use plastic (ABS or PLA) for the material?.. I was thinking of 3D printing it.

I could print variants with mild dimension differences to fine tune my design. I just need the horn length and diameter.

  • 0
    TI__Mastermind 27950 points
    Hi Kevin,

    The BOOSTXL-PGA460 daughtercard includes two muRata transducers. Are you referring to the transformer driven MA58MF14-7N or direct direct driven MA40H1S-R? MuRata has characterized the MA40H1S-R's FOV with variant horn designs. You will need to contact their support channel to request this application report since they manage the release of this content. I have not seen a similar report for the MA58MF14-7N, though you should still ask them.

    We have 3D printed horns with success, so the ABS or PLA material should be fine.

    Because TI does not have transducer / wave guide design expertise, the only guidance I can offer is mentioned in the PGA460 FAQ #4.4.9 ( www.ti.com/.../slaa733.pdf ). In short, the wider the diameter and longer the horn, the more concentrated the echo energy will be in the forward facing direction.

    If you can afford to add a horn to your system, I do recommend it. However, both muRata sensors on the EVM should be able to reach 3~5m without the aid of a horn. Are you trying to reduce side lobe reflections my adding a horn so that you only detect forward facing objects? What type of objects are you trying to detect?
  • 0 in reply to Akeem Whitehead
    Prodigy 160 points

    I was referring to the transformer driven one.

    I wanted to use the horn to limit the FOV to detect only forward facing objects.

    Since you mentioned that you did try to print the mounts, could I acquire the same CAD models that you used? I just need a basic one to start with

  • 0 in reply to Kevin Abishek
    TI__Mastermind 27950 points

    Hi Kevin,

    I will need to check if we have any CAD models available. In the meanwhile, you may want to consider using a completely different transducer. The muRata MA58MF14-7N was designed for automotive park assist, so it was designed to have wide horizontal coverage, and a small amount of vertical coverage to prevent detection of the ground or curbs.

    A very common closed-top forward facing transducer is the 40kHz SensComp 40KPT25 (Prowave 400EP250). Because this transducer is designed with a wide diameter (25mm), it's total beam angle is only 24° degrees (+/-12 °), and is able to detect forward facing objects at very long range. I've tested this transducer to easily detect a wall up to the maximum record length (which is about 11m).

    To compare this transducer to other options, the beam angle is provided as a filter option in the transducer selection guide at: e2e.ti.com/.../620399

  • 0 in reply to Akeem Whitehead
    Prodigy 160 points
    Ok please do.
    Regarding using alternate transducers.. in the user input program of Energia's GetDistance program, should I skip the transducer settings as the one I change to might not be the same as the two listed in the prompt.
  • 0 in reply to Kevin Abishek
    TI__Mastermind 27950 points
    Hi Kevin,

    When using a different transducer in the Energia sketches, you have two options:
    1) Skip the transducer selection option with 'x' when prompted, but be certain you have pre-programmed the EEPROM with the appropriate settings using the GUI beforehand.
    2) Add an additional case statement to the PGA460_USSC.cpp library file file with the predefined device settings for your new transducer. Currently, only two case statements are available for the two muRata transducers available on the EVM, but you can have a total of ten cases in the defaultPGA460 library function.
  • 0 in reply to Akeem Whitehead
    Prodigy 160 points
    Okay, please try to share those CAD files also.
    Thankyou.