Hi all
Ive got a project that im working on and I need a sensor to detect the distance of a user up to say +- 6 meters with a accuracy of about 500cm.
It is for outdoor application and the user and device will be moving about.
I have looked into rf which doesnt seem plausible and bluetooth(not sure about that), I have also looked into ultrasonic sensors but then I need a receiver or sender on the user which has timing issues and then I would need rf modules to send data back etc unless you guys know of ultrasonic sensors that could work with a receiver on the device and a sender on the user with communication between the two?
Please there has to be something simple out there and cheap lol.
Thanks for any help or pointers chaps.
Well, There are those ultrasonic distance sensors for Arduino... I don't think each one has their own frequency, so I suppose one can receive the others signal. So wiring the Arduino output to the ping input of one while listening to the echo of the other might work. You could sync the 2 Duinos over something few orders of magnitude faster, such as rf, or even connect wires and sync it once and then measure the ping... this being said, you would probably need like a ball of the transducers and receivers. 
Yes I have been able to get the basic hcsro4 to work with rf modules but I did not think of syncing them once everytime you turn the system on because I really dont want to use rf to send info back and forth.
I am going to try that and see thanks
NP, just did a back of the envelope plausibility check and it seems like it takes sound about 1/300 s to travel a meter, so you will get plenty of resolution without having to worry about the desynchronisation, because that's going to be few orders of magnitude lower.
