Sensor to measure up to 10 metres


I'm thinking about a project to measure distances of solids with a range of 10 metres. The idea is that my arduino could recive a signal proportional to the distance, and then, arduino would send a signal to my pc with the data.

The problem is that I don't know a "cheap" sensor that measures this ranges. The accuracy is not a problem. A 5% error would be acceptable.

I've seen on the internet some sensors there , but are a bit expensive for me.

Has anybody ever used a similar sensor?

Thanks !!

interesting question!

expensive - -

FYI, (read when searching for the sensors above)

with ultrasound range sensors the signal strength goes down with the 4th power of the distance. ==> doubling the distance gives 16 times less signal back!