TDC1000: TDC1000 for Air Velocity Measurement

Pejman Hashemi

Prodigy 20 points

Part Number: TDC1000
Other Parts Discussed in Thread: TUSS4470

Tool/software:

Hi,

We want to measure the air velocity in a tunnel using tdc1000 and ultrasound transducer.

Most of the examples of the tdc1000 are related to the fluid measurement.

Do you know if we can use this IC with ultrasound transducer at Frequency of 40KHz for air velocity measurement?

The transmitter is mounted to the wall of the tunnel on one side and the receiver is mounted on the other side with 45 degree angle to measure the time of flight and then air velocity.

It needs two microcontroller. Do you know what is the best method for the handshaking between transmitter and receiver as one micro is one side and the other micro is on the other side.

Maybe using RS485 hard wire from transmitter to trig the tdc1000 and then the receiver, receives the RS485 signal and turn the TDC1000 to RX mode to receive the pulse and calculate time of flight?

Thanks,

Pejman

4 months ago

0 Eddie LaCost 4 months ago

TI__Mastermind 40400 points

Hello Pejman,

Yes, the TDC1000 can support 40kHz transducer frequency, but I would actually recommend a newer higher performance device, such as the TUSS44x0.

See the FAQ below. The TDC1000 has a known behavior where STOP pulses can be missed which could affect your accuracy.

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/724028/faq-tdc1000-everything-you-need-to-know-for-ultrasonic-tof-liquid-coupled-collateral-tools-designs-faq

For the TUSS4470 device, you could use the start of pulse generation of the TX device to enable RX on the receiving device.

0 Pejman Hashemi 4 months ago in reply to Eddie LaCost

Prodigy 20 points

Hi Eddie,

Thanks for reply.

We specifically want to use TUSS4470 for tunnel air velocity measurement on up to 20 meters.

Transmitter is on one side and receiver is one the other side.

As the transmitter and receiver are separated from each other, we are not sure how to sync two MCUs on the transmitter and receiver side to tell the receiver when the transmitter signal is sent.

Regards,

Pejman

0 Alicia Rosenberger 3 months ago in reply to Pejman Hashemi

TI__Genius 9490 points

Hi Pejman,

Eddie is currently out of office. He will be back next week and should be able to get back to you then.

Best,

~Alicia

0 Eddie LaCost 3 months ago in reply to Pejman Hashemi

TI__Mastermind 40400 points

Hello Pejman,

We do not include a firmware example, but synchronization could be accomplished using a GPIO on the connected microcontroller. When the first device starts the transmit, the MCU would toggle a GPIO that is connected to the second device's MCU that would allow the two devices to synchronize.

If you are only performing the time of flight measurement in one direction, you could use the second device in a receive only configuration, so that no synchronization is required. The TUSS44x0 devices use SPI communication, so you likely would want to use some other communication protocol for 20m wire length(UART, RS232/485, etc).

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TDC1000: TDC1000 for Air Velocity Measurement