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MSP430 reference design recommendation for distance measurement application (ultrasonic sensor)

Serdar Köse
Genius 3360 points

Other Parts Discussed in Thread: CC2630

I have a closed box that is going to be filled by solid materials. I am looking for a reference design that can measure how full is the box. 

It is a battery powered application that I need small foot print, low power, low cost MCU. The max and min distance are about 1 m to 3-10 cm (flexible).

Is http://www.ti.com/tool/TIDA-00151 a suitable ref. design to measure fullness of a box (current distance /  the initial distance) or would you suggest a different reference design?

  • 0
    TI__Mastermind 25045 points
    Hi Serdar,

    It seems like your post is incomplete. No really sure what the question is...

    Thanks,

    David
  • 0 in reply to DavidL
    Genius 3360 points
    Thank you David, I updated the question. I don't know why the sentence was missing.
  • 0 in reply to Serdar Köse
    TI__Expert 4690 points

    Hi Serdar,

    If the material in the box is going to be metallic material then you might also want to consider LDC1xxx reference design such as:

    http://www.ti.com/tool/TIDA-00460?keyMatch=distance measurement&tisearch=tidesigns

    http://www.ti.com/tool/TIDA-00215?keyMatch=distance measurement&tisearch=tidesigns

    Also there is an msp430 app note which provides a design to obtain distance measurement using the msp430 and 40KHz ultrasonic transducers. However, I am not sure if this design will meet your small form factor requirement.

    http://www.ti.com/lit/an/slaa136a/slaa136a.pdf

    Regards,
    Ivan

     

  • 0 in reply to Ivan Calzada
    Genius 3360 points
    Thank you Ivan for the answer,

    It is a plastic container. SLAA136A might be a better choice. Do I understand correct that I can use any MSP430 as long as it has a timer to count the transmit frequency and a comparator to sense echos. If it is the case, my goal is to connect it to CC2630, then I can use 2 pins of CC2630 for that purpose.

    SLAA136A says that that design can measure the distance between 20 to 250 cm. cache.freescale.com/.../AN3481.pdf says it can measure from 5 cm ( to 40 cm I guess). What needs to be changed at SLAA136A in order to measure shorter distances? Is it something to do with the circuit and signal processing or the transducer?

    I am searching about the available transducers, do I need to use Electromagnetic or Piezoelectric type? I guess higher the sound pressure level is better. Does it matter if it is rectangle, round or square shape signal transducer?

    "SLAA136A - October 2001" doesn't have a newer version, right?
  • 0 in reply to Serdar Köse
    TI__Expert 4690 points

    Hi Serdar,

    Serdar kose said:
    It is a plastic container. SLAA136A might be a better choice. Do I understand correct that I can use any MSP430 as long as it has a timer to count the transmit frequency and a comparator to sense echos. If it is the case, my goal is to connect it to CC2630, then I can use 2 pins of CC2630 for that purpose

    Yes, the only requirements is that the MSP430 has a comparator and a timer. If your design does not require an LCD module then you might want to consider a MSPG2x55 device which has a Timer_A and a COMP_A module.

    Serdar kose said:
    SLAA136A says that that design can measure the distance between 20 to 250 cm. cache.freescale.com/.../AN3481.pdf says it can measure from 5 cm ( to 40 cm I guess). What needs to be changed at SLAA136A in order to measure shorter distances? Is it something to do with the circuit and signal processing or the transducer?

    Reducing the amplification gain of the Rx transducer op amp should reduce the sensitivity of the design. Adjust R7, C5 and R5.

    Serdar kose said:
    I am searching about the available transducers, do I need to use Electromagnetic or Piezoelectric type? I guess higher the sound pressure level is better. Does it matter if it is rectangle, round or square shape signal transducer?

    If the size of the transducer is not a problem in your design, I would suggest using a Piezoelectric type since typically piezoelectric type draw less current and they don't produce magnetic fields which could cause some EMI in the design. 

    Serdar kose said:
    "SLAA136A - October 2001" doesn't have a newer version, right?

    Correct, that is the latest version.

    Hope this helps,

    Ivan

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