Battery-free PSIcle sensor transmits tire pressure data to smartphones
Checking your bike's tire pressure can be a fiddly process, which is why there are now valve stem attachments that let you check it with your smartphone. The just-announced PSIcle sensor makes things even easier, as it doesn't require a battery.
They proceed to continuously monitor the air pressure, utilizing Bluetooth or ANT + to wirelessly transmit that data to an app on the cyclist's phone. Because they're battery-powered, however, they regularly need to be recharged, plus they're heavier and bulkier than they would be otherwise.
Austrian manufacturer Tubolito recently took a different approach, with an inner tube that incorporates a pressure-sensing NFC (near field communication) chip. That battery-free chip is temporarily powered up by the radio waves emitted by a nearby NFC-capable smartphone.
As a result, users can check their tire pressure simply by stopping and holding their phone close to the chip. That said, because the chip is integrated into the tube, it can't be used with tubes made by other manufacturers, or with tubeless tires … and that's where the PSIcle sensor comes in.
Created by Minneapolis-based engineers Chris Larsen and Jeremy Hipp, the waterproof device is simply screwed onto the end of a third-party tube or tubeless rim's Presta valve stem – the only stipulation is that the stem does need to have a removable core. Once in place, it works much like the Tubolito tube … it's powered as needed by a smartphone held about 1 inch (25 mm) away, transmitting air pressure readings to an iOS/Android app on that phone.
The PSIcle sensor itself is made of anodized aluminum coated with EPDM rubber, it measures 40 mm long by 6 mm thick by 22 mm in diameter, and reportedly tips the scales at just 5 grams. It's being offered in two versions: the LP, which reads mountain bikes' tire pressure from 0 to 40 psi (2.75 bar) – plus or minus 0.06 psi – and the HP, which reads road bikes' tire pressure from 0 to 400 psi (27.5 bar) – plus or minus 0.7 psi.
Needless to say, both models are intended for use while the bicycle is not in motion. It should be noted that the TyreWiz and Airspy do transmit live readings as the bike is moving, sounding an alert if the pressure gets too low.
Should you be interested, the PSIcle sensor is presently the subject of a Kickstarter campaign. Assuming it reaches production, a pledge of US$52 will get you a set of two – the planned retail price is $56 a pair.