What is it?

The TMP007 is an infrared (IR) thermopile sensor that measures the temperature of an object without contacting the object. The integrated thermopile absorbs the infrared energy emitted from the object in the sensor field of view. The thermopile voltage is digitized and provided as an input to the integrated math engine, along with the die temperature. The math engine then computes the corresponding object temperature.

The sensor is broken out in a small form factor board that can be directly mounted onto the Teensy or developed into a "wand" sensor for reading temperature of objects without contact. The sensor is very low power (<270 microAmp) allowing the board to be powered from digitalWrite(HIGH) and digitalWrite(LOW) for 3V3 and GND, right on the Teensy 3.1 board or from any 3V3 compatible GPIO pins on an Arduino or other board. There is an interrupt broken out to alert the microcontroller of threshold crossing and one of two address pins is broken out so two of these sensor boards can be on the same I2C bus line at the same time without conflict.

The sensor accuracy is sensitive to nearby heat sources so caution is warranted when mounting the sensor board directly onto a microcontroller like the Teensy; the Kinetis processor generates a fair amount of heat and can skew the thermopile results. Consider placement and mounting for best results in your application.

This sensor is particularly useful for measuring temperature of animals, hot or difficult to handle objects, dangerous objects, liquids, etc. The thermopile sensor is precalibrated for generic use but has non-volatile memory writable up to eight times to hold user calibration coefficients for specific use cases for optimal accuracy.

The sensor comes in a BGA package which is a little challenging to assemble but the resulting board is very easy to use.

Why did you make it?

I love remote sensing and this small IR thermopile sensor allows pretty accurate non-contact temperature measurements over a generous range (0 to 60 Centigrade) of temperatures. I could have wished for an even wider range; specifically it would be useful to measure temperatures around the boiling point of water (100 Centigrade). I would also like to point it at the night sky and see 3 degrees Kelvin! Not with this thermopile, but there are a lot of more practical uses with which one can put the sensor. In addition to basic temperature, the thermopile can be used to measure the presence of a warm object. By taking advantage of programmable threshold and the integrated alert (interrupt) function, changes in temperature can be accurately detected.

What makes it special?

This is a small sensor broken out on a very small board that has a variety of very practical uses. I wrote a small sketch that parametrizes the registers, initializes the sensor, and gets properly scaled temperature data out. The data registers have a rather unique 16-bit size, requiring a bit of finagling of the usual I2C read and write functions.

Order the board from OSH Park and assemble your own, or order the fully assembled and tested board from me and see how much fun it is to make remote measurements of your pets and friends!