Always taking the weather with you? Here’s a cool thermometer dongle for better readings


Here’s a neat new Kickstarter project: a tiny ambient thermometer that you can plug into your smartphone or tablet. Because your mobile device doesn’t have enough sensors already.

The device is called Thermodo and, appropriately, it comes from Danish software firm Robocat, which was responsible for the graphically intriguing Haze weather app. Smartphones do already have thermometers in them, but those are for keeping an eye on the handset’s internals: this would be for checking the temperature around you.

The interface with the mobile device is quite interesting: unlike iCelsius, a range of iOS-compatible thermometers designed for cooking and educational purposes, Thermodo doesn’t plug into the dock connector. From the Kickstarter blurb:

“Thermodo consists of a passive temperature sensor built into a standard 4 pole audio jack enclosed by a sturdy housing. This allows your mobile device to read Thermodo’s temperature straight from the audio input. Thermodo sends an audio signal through the temperature sensor. This sensor will then attenuate the signal amplitude depending on the actual temperature. This attenuation can now be detected on the microphone input and through software we calculate the corresponding temperature. Easy peasy!”

Because all mobile devices have headphone jacks, Thermodo should theoretically work on all smartphones and tablets. Robocat founder Willi Wu told me a companion app will be made available for iOS first, although it will also work with the company’s existing Thermo app on Android.

If it works as advertised, then Thermodo might be quite useful for budding meteorologists. “Thermometer” apps (including Robocat’s Thermo) tend to simply use location-based weather data, whereas this seems to be the real deal — think users being able to feed weather data to the cloud, rather than simply drawing data from it. What’s more, Robocat will also release a software development kit for Android, so the device may find itself being used in a new generation of temperature-aware apps.

However, one of the most immediate problems that springs to mind with the Thermodo concept has to do with heat sources that might distort the device’s readings. The first of those heat sources is the smartphone or tablet itself: here, Wu told me the software compensates, plus “we improved the design of Thermodo in a way that we could thermally decouple the sensor from the mini jack”. And then there’s the pocket problem. Thermodo will generally be carried around in a pocket — as this is a much more unpredictable heat source than the mobile device, how does the team get round it?

“When you plug Thermodo into your device you will read Thermodo’s temperature in its environment. Hence, if you have it in your pocket you will get the temperature of your pocket,” Wu said. “However, we are trying to detect rapid changes in temperature and make the user aware of it. We are even experimenting with some prediction algorithms in order to reduce the effect of this.”

According to Robocat’s timetable, the company hopes to ship units in August. The cost is likely to be around the $30 mark, and it will come in black, white, and anodyzed aluminum. They’re looking for $35,000 in funding, and here’s the pitch:

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