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TDC1000: Using 300kHz ultrasonic with TDC1000

Shankaranarayanan P V
Intellectual 270 points
Part Number: TDC1000
Other Parts Discussed in Thread: TDC1011

Hello,

 I am trying to recognize the material using the echo pulse reflected, for which I am using a 300kHz ultrasonic sensor(DPU1007CJ300-02). I have interfaced atmega328 with tdc1000, and have connected a 1k resistor in RX path. I have also enabled resistive feedback mode and increased the gain to 21dB. But I am not receiving any echo. Is there anything else I need to change or any configuration that I need to enable so that I can receive echo..? Another experiment I tried is exciting one 300kHz transducer with 10 pulses and made another transducer to receive it. Which works perfectly fine, but when the signal reaches LNAOUT pin, it seems to vanish, I have tried bypassing the LNA, but to no avail. And no output on COMPIN as well What should I do?

Regards,

Shankar

  • 0
    TI__Genius 11015 points
    Hello Shankar,

    Let me know if your send me a schematic of your setup along with the spec sheet of the transducer that you are using.
  • 0 in reply to Bharat Aravamudhan
    Intellectual 270 points

    Above is the schematic of my setup, where I have used TDC1011 instead of TDC1000. In the receiver path, I have connected a 1K resistor, I have not implemented the RTD section yet. And for the time being, I have used another module for temperature measurement. As you can see I have changed the value of the capacitor connected to the LNAOUT pin(C27) to 2.2nF. And the capacitors connected to the COMPIN was changed to 300pF(C28, C24). I connected the sensor to the J5 connector.

    For testing purposes, I created a setup of two ultrasonic sensors, where one was acting as a transmitter and the other as a receiver. The transmitter was excited with 10 pulses. After connecting the receiver I could read an echo pulse of an amplitude 10mV. In the receiver, I have disconnected the tx pin so that it does not interfere with the receiver. 

    The problem is I cannot read the echo pulse from the LNAOUT pin, which should not have been the case since I could read the echo pulse at the Rx pin. I have tried bypassing the capacitor at LNAOUT pin. And also enabled resistive feedback mode.

    What should I do?

  • 0 in reply to Shankaranarayanan P V
    TI__Genius 11015 points
    Shankar,

    Please check transducer is mounted properly to the system. Also make sure the reflecting surface focuses all the waves back to the transducer.

    Per the schematic that you had provided I do not see a reason why the setup cannot work. I would also try to setup the same transducer as both Rx & Tx and check if the setup works.