This is the Thermal Anomaly Device (TAD) made by Scire
It measures changes in the temperature of the room and provides an audio and visual notification if it detects and sudden hot or cold spots.
If it detects a sudden drop in temp, it lights up blue, and provides two tones which descend, if the temperature goes up, it lights up red and provide two rising tones
I filmed a quick video on how they work:
The TAD is 11cm long x 3.5cm high x 5.5cm wide & requires a 9v battery (not included)
When the device starts, it performs a system check and displays a colour cycle pattern
It then flashes yellow during a period where it logs temperature 100 times. This calibrates the device to your environment.
After that point, it measures the temperature every half second, and if this temperature deviates from the average of the past 100 readings by 0.5 degrees, it raises the alarm.
It also has a function which prevents false alarms. So, in other temp sensors, when a cold spot is recorded, they tend to then give a hot spot alarm as the temperature returns to normal. The TAD doesn't do this. So when you see a hot or cold spot alarm, you can be sure that something new has actually happened.
This device was designed, programmed and built by paranormal investigators, for paranormal investigators. No gimmicks or toys, just useful equipment to help further the research into the field