One of my ongoing projects is to develop a low-cost thermal imaging camera. In this video, I take apart an Extech IR250 infrared thermometer with the intention of grabbing an analog or digital signal so that I can record temperature measurements while using a scanning or image processing device to select portions of the scene being examined. Unfortunately, it looks like the analog circuitry is completely sealed inside a custom IC that is hidden under a blob of potting material. I'll remove the IR sensor from the board and build my own analog amplification and digitization hardware.
Common digital output IR thermometer sensor:
TPS334 sensor datasheet:
Analog Devices app note regarding thermopile sensors:
Servo pan/tilt IR imaging scanner project:
Redshift thermal imaging: