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Sensor to detect direction over a longer range

marjasin

I want to create a camera that can follow a person around ( a football player on a pitch). Both Ultrasonic and IR-sensors would be way to short range since the maximum distance could be as much as 100 meters. Do you have any ideas on what to use for this application?

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  • Hi Freddy,

    Can the player wear a small radio transmitter about the size of a USB memory stick?

    If so, it could send a ping every second or two and 2 receivers separated by 10 or more meters of cable could figure out the angle from the difference in time of arrival of the ping. The first receiver to get a ping would start a timer that counts until the second receiver gets the same ping. The comparators and timer trigger would be on the cable half way between receivers. Accuracy of the measurement would need to be about 1 nanosecond. (1 GHz clock)

  • in reply to dougw

    Yes, that would be possible and also maybe prefferable. What kind of transmitter/recievers could you recommend?

  • in reply to marjasin

    I would use the cheapest radio modules I could find in the 2.4 GHz band for a couple of dollars each, as long as they claim to transmit far enough. I would likely have the person-mounted transmitter broadcast a continuous square wave at some frequency like 1 KHz and then compare the phase of this signal from the two separated receivers. Note that the phase difference is only going to be nanoseconds, so your phase discriminator will need to be able to measure small phase differences.

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  • in reply to marjasin

    I would use the cheapest radio modules I could find in the 2.4 GHz band for a couple of dollars each, as long as they claim to transmit far enough. I would likely have the person-mounted transmitter broadcast a continuous square wave at some frequency like 1 KHz and then compare the phase of this signal from the two separated receivers. Note that the phase difference is only going to be nanoseconds, so your phase discriminator will need to be able to measure small phase differences.

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