Thermal imaging can be used to document heat/AC leaks from insulation gaps on a building's facade, reveal warmer ground water inflows (either fresh or chemical-laden) or "thermal pollution" from industrial processes entering ocean-temperature waterbodies, as well as identify areas on the human body experiencing infection or stress (includes epidemiological applications).
Community applications so far include both a "heat-busters" program in East Harlem and a "forensic" water quality monitoring program in the Gowanus Canal.
There are three prototypes in development:
- A Thermal Flashlight (described on this page): a RGB LED flashlight with a non-contact infrared sensor that "paints" the temperature of the surface directly on the wall for capture with a second timelapse camera.
- Thermal Fishing: dragging a thermometer through the water, taking contact measurements mapped to a RGB light, also for capture with a second timelapse camera.
- A scanning thermal camera on a lego turntable (software also in development) that sweeps back and forth across a scene, recording the temperature variation to build up an image.
"FLIR" cameras can produce images such as the one below, and are typically used to identify heat leaks, but even low-resolution FLIR cameras can cost thousands of dollars. Our goal is to make this kind of investigation (and the potential savings) cheap, easy, fun, and informative for those of us without $10k in our pockets.
The first approach results in a kind of "light painting" -- a color heatmap overlaid directly onto the scene. This is the simplest, cheapest, and to date, most effective way we have developed of measuring heat leaks or cool leaks indoors and outdoors. Simply put, the "flashlight" puts out red light if it's pointed at something hot (default 75 deg F or more) and blue light if it's pointed at something cold *(default 60 deg F or less):
To capture the light painting over time, we have been using timelapse photography or GlowDoodle, as seen in the top image on this page.
Building your own
- 1 Melexis MLX90614 non-contact IR thermometer (3v)
- 1 common-cathode RGB LED
- 2 4.7k Ohm resistors
- 2 100 Ohm resistors
- 1 180 Ohm resistor
- 1 0.1 μF capacitor
- a breadboard or circuit board & soldering eqmt.
- 9v battery and holder
These research notes will be integrated into this page to provide instructions on building and using your own thermal flashlight:
- http://publiclaboratory.org/notes/warren/12-12-2011/circuit-diagram-simple-thermal-flashlight (includes source code)
- http://publiclaboratory.org/notes/ad/11-28-2011/thermal-camera-arduino-uno-mlx90614-ir-thermometer (includes source code)
Several meetups have been organized to build and test thermal flashlights, at RISD (Providence, RI) and in Brooklyn, NY. We are organizing one now in Somerville, MA: