Today’s sensor-packed smartphones can measure a lot of things, but ambient temperature generally isn’t one of them. It is possible to buy separate Bluetooth temperature-sensing modules, and it’s been suggested that mobile devices could use beams of infrared light to obtain spot temperature readings. The Thermodo, though, is considerably more straightforward – it’s a tiny electrical thermometer that plugs into the phone’s headphone port.
Here’s how it works …
The Thermodo itself is based on a standard four-pole audio plug, but it also contains a passive temperature sensor. An audio signal is sent through that sensor – depending on the temperature surrounding the phone, the sensor will attenuate the signal amplitude differently. The phone’s microphone picks up the altered signal, and relays that data to the accompanying app. The result is a real-time onscreen display of the temperature.
One of the Thermodo’s limiting factors is the range of temperatures it can measure: -20 to 50ºC (-5 to 120ºF). The designers are quick to point out that the stated operating range of the iPhone 5 is 0 to 35°C (32 to 95° F), but that still may limit its usefulness for some applications.
Copenhagen-based start-up Robocat is currently raising production funds for the Thermodo on Kickstarter, and has already far exceeded its funding goal – apparently a lot of people want a thermometer for their smartphone. A pledge of US$25 will get you one. Via Thermodo adds a thermometer to your smartphone.