iSleepWell is useful to turn airplane mode ON when going to bed (for example) by just putting your iDevice beside you on the screen side. (face-down). It detects that position and turns off all radios. You can sleep without being disturb by unsolicited calls and you are not bombarded by negative waves.
Enabled: if ON (default), iSleepWell will detect the sleep position and react as expected. If OFF, it does nearly nothing except waiting to go ON.
Play Sound: when the airplane mode is about to be triggered the device says Airplane mode enabled. This let you put it on the right side to prevent the mode change. When you take back the device in your hand, the device says Back to normal.
If OFF, no sound is played.
Vibrate: when airplane mode is actually changed, the device vibrates if ON.
Scan interval: iSleepWell polls the accelerometer state each X seconds : 5 and 10 are good choices.
Screen down: by default you have to put the device on the screen to trigger the airplane mode. you can change that behavior by setting this switch to OFF. Useful to test and see the plane too...
Active on sleep mode: when you let your device without using it at all, it goes to suspend state and the applications receive no CPU time from iOS. This switch set to ON awakes to device every 15 minutes to check if the position have changed. So turning your device may not trigger the airplane mode right now if it is in hibernation. This will consume very few battery. You can set it to OFF if you fear for your battery, but I did not notice significant change.
Disable on manual change: if you set Airplane mode by yourself (when you are aboard a plane ;)), iSleepWell will detect this state and will disable itself until you reenables the radios by yourself. Setting this to OFF, will let iSleepWell to reenable the radios. It's safer to let this to ON.
Prevent from running: if set to ON, iSleepWell will exit completely and will be unable to do anything. The only ways to relaunch it is to respring or reboot the device after putting this toggle to OFF.
You can get iSleepWell from the Cydia Store for $0.99.