Nice project! There's a whole bunch of indoor positioning methods, having different precision/simplicity/cost profiles, so you might need to shop around. Prob

Nice project! There's a whole bunch of indoor positioning methods, having different precision/simplicity/cost profiles, so you might need to shop around. Probably cheapest and closest to my sensor is ultrasound sensors like http://www.marvelmind.com http://www.marvelmind.com