Parking sensors are not cheap. These little bumper-savers can cost hundreds of dollars on their own, and they're often lumped into packages costing far more than that. One company thinks it can out-do the automakers at their own game, using a license plate frame. Technology's pretty great, innit?
The company is called FenSens, a truncation of fender sensor. It's a license plate cover with innards similar to the parking sensors you might get from the factory. You install the cover, pair the plate frame to your iOS or Android device via Bluetooth, and Bob's your uncle.
It detects things up to 10 feet away from the car, and it will send visuals, audio and vibrations to your phone, so you don't even need to take it out of your pocket to get your parking done. After five months, you remove the rechargeable battery, plug it in for two hours, and you're good to go once more.
The company claims it works with all vehicles no longer than 30 feet, likely because of low-energy (LE) Bluetooth constraints. It also has a limited vertical range, so if your plate frame is more than 4 feet off the ground, it may not work that well.
FenSens is almost surprisingly inexpensive for what you get. Right now, it's offering $99 early bird pricing, but retail is $149, which is still cheaper than any parking-sensor system I could find on an automaker's site. If you have an older car that never had the option for sensors, or if you're just plain cheap, this doesn't appear to be a bad way to go.