Sensors that might do the work:
- Wii remote (wiimote) and infrared LEDs
- Ultrasonic Range Finder (up to 6 meters rage with 50 degrees of angle-wall interferance):
Sonic range finders work by emitting a series of supersonic pulses (typically in the range of 40 kHz), which propagate outward from the sensor in a cone shape at the speed of sound (around 0.9 ft/ms in room-temperature air). When encountering an object, the pulses reflect, returning an echo that is detected by the range finder. The time-to-echo is then recorded by the range finder and can be accessed once the ranging is complete.
The minimum range of the SRF is limited by the time it takes to emit a pulse and eliminate any residual ringing in the sensor, typically on the order of 100 usec (microseconds). The maximum range is limited by the power of the pulses, among other things: after a certain range, the echoes are simply too weak to be reliably detected.
Problems:
- If the range is big enough the angle will be also big and maybe there is an interferance coming from the signal hitting the walls. How can we get accurate results?
Useful links:
- http://itp.nyu.edu/physcomp/sensors/Reports/SonarRanger
- http://www.acroname.com/robotics/info/articles/devantech/srf.html#e11
- http://www.sparkfun.com/commerce/product_info.php?products_id=639 with a live example: http://flickr.com/photos/aallan/2478674311/in/set-72157604485044549/
- http://www.arduino.cc/en/Tutorial/UltrasoundSensor
- http://webzone.k3.mah.se/projects/arduino-workshop/projects/arduino_meets_processing/instructions/ultrasound.html
- http://www.maxbotix.com/MaxSonar-EZ1__FAQ.html
- LV-MaxSonar-EZ1-Datasheet.pdf
- MaxBotixNewProducts.pdf
- PING-v1.5_documentation.pdf
- Distance_measurment_PING.pdf
- geek_robot.pdf
- examples of using ultrasonic range finders:
- http://www.youtube.com/watch?v=fBtEjIX4pmc
- http://www.youtube.com/watch?v=bZIKbuZaJSQ
- http://jamesalliban.wordpress.com/category/arduino/
- http://www.vimeo.com/1379563
- http://portfolio.barbariangroup.com/nextfest/index.html
- for use with maxMSP: http://www.cycling74.com/forums/index.php?t=msg&goto=154604&rid=0&srch=arduino+max#msg_154604
- Infrared Proximity Sensor:

- Lasers and light sensors (red spot visible)

Problems:
- Limited 6 pins input from the arduino may result in limited control or unsmooth interaction (tests needed)
- The laser (x6) needs to be connected in power source (x6)
- Optical Detector / Phototransistor:
- Video Tracking Method (with normal or infrared camera/nightshot):

Problems:
- Maybe the light from the projection is not enough to detect persons in the screen so we could use an IR camera (bought one from tradera.com)
Usefull links:




