Barometric Pressure / Altitude

Image Description Datasheet Distributor Eagle Lib
Digital barometric pressure/temperature BMP085 Digikey Adafruit:BMP085


IC (chip) sensors

Analog temperature sensor
-40 C - 125 C
TMP36 Digikey Analog Direct
Digital temperature sensor
-55 C - 125 C
Dallas 18B20 Digikey mouser Maxim Direct


Platinum wire resistive sensors

Class A

±0.03 to ±0.15 °C accuracy

Class B


Geiger Mueller Tubes - Handy for people looking to make random number generators or detect radiation. Tubes tend to be Cold War old stock from Russia/US, and tend to be used for detecting Gamma and Beta radiation. You'll need a high voltage boost supply - check nixie tube projects for some HV supply designs

Here are some places you can find tubes and kits: Chaney Electronic goldmine Ebay United Nuclear