Modern Android-powered smartphones include a whole bunch of sensors, light sensors, accelerometers, digital compass, GPS, temperature, and more! They also include a proximity sensor which measures how close the phone is to another object, like your face.
Apparently some people have reported problems with their Desire HD’s screen failing to turn off when on a call, and the screen turning off when on a call but failing to turn back on. The latter requires the battery to be removed to be able to use your phone again. All due to problems with the proximity sensor calibration.
Most reports come from those who have loaded a custom ROM or kernel on their device, but some stock devices have reportedly had the problem as well, though HTC has addressed the issue in kernels 1.32 and up. If your kernel is pre-1.32, eventually you’ll suffer this type of problem.
The obvious fix is to upgrade your kernel, but a workaround from XDA-Developers lets you recalibrate your proximity sensor at will — or turn it off entirely.
If you’ve suffered this problem we’d love to hear about it in the comments (be sure to include any frustrating or funny stories that it caused as well)! If you’re still on a pre-1.32 kernel are you more likely to upgrade, or to use this app? Let us know that in the comments, too!