blitzalpha

I'm attempting to build a tracking system that will consist of a robot containing a receiver that will follow and track a transmitter that will be attached to a mobile user. I want the robot to maintain a 2 meter distance from the user so if the user accelerates, the robot accelerates, or if the user decelerates, the robot decelerates. I'm wondering which type of sensor I should use to measure the distance between receiver and the transmitter. I've done some research on rf, infrared, and sonar sensors, however, I'm not exactly sure which would be best for this application. Would it be possible to measure the distance with just a transmitter and receiver or would I need transceivers?

falleafd

The best choice is ultrasonic range finders.

IR is usually worked at range from 10 cm to 80 cm, for example GP2D12

But for you range from 3cm to 3m or farther, sonar sensors are the best choice.

SRF04 has a range from 3cm to 3m
SRF08 which has I2C interface work from 3cm to 6m and you can set it manually to 12m range

But the fact that you should choose Polaroid 6500 module, of which price is lower than SRF08 but it has a good range and module from 1 cm to 10m

However, if you only use sensor for this only application SRF04 is better because it's very simple with only 4 pins available, and its range is enough for you, and it costs only about 25$.

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