Sensors for Atmels with some examples see: http://onecall.farnell.com/ (account, next day, no minimum order) http://rswww.com/ (account, next day, no minimum order) http://www.maplin.co.uk/ (account, minimum order, beware often 0 stock) http://uk.digikey.com/ (account, £50 min http://www.sparkfun.com (credit card only, USA based, so import delay) Environmental: Sensor Example device Interface temperature SHT11 2 wire, clock and birirectional data temperature LM19 Analogue voltage pressure SCP1000 SPI, I2C humidity SHT11 2 wire, clock and birirectional data location (GPS) Quinetiq Q20 Serial light intensity IR sparkfun colour TSC230 = 489-1211 3x Frequency magnetic field reed switch, hall effect biometrics touch COM-07902 (sparkfun) I2C Mechanical shock F 540-626 Switch tilt movement F 732-795 Digital output force tap (piezoresistive) proximity (capacitative) proximity (ferrous) liquid level liquid flow accelerometer SCA3000 SPI displacement LPDT Potentiometer strain ultrasonic gyroscope WIImote Electrical voltage Use A to D current Small resistor, measure voltage potentiometer Use A to D magnetic card RFID radio receivers (eg FM, WiFI..) Often Serial