ranging sensors
Acroname Aug 29,2003
Acroname - They carry some nice H-bridge chips, and sensors. Great articles on how to use their products as well.
Banner Engineering Aug 29,2003
Banner Engineering - make some nice beam-break sensors...
GPS Receiver module Sep 29,2003
Motorola has a one-chip GPS solution. I haven't used it, but Will O'Halloran has, and has gotten good results.
Hacking a PIR motion sensor Aug 29,2003
Hacking a Motion Sensor - for those cheap motion sensors you get in security lights...
Laser range finders Oct 10,2004
They're not cheap, but they are pretty accurate, and they communicate serially. If anyone knows of a cheaper one, or knows how to make your own, let me know.
Maxbotix Ultrasonic Sensor Jan 4,2006
The Maxbotix ultrasonic sensor looks like an interesting model, in that it's smaller than most ultrasonics, and has a number of different interfaces: serial, PWM, and analog.