Which Way Back? 2.2 released!

Another free update and this time it adds a brand new feature:

Pocket Mode


I’ve been planning this addition for quite some time and after a lot of testing I’m finally ready to include it in ‘Which Way Back’. Get it here.

When I use this app, most of the time I don’t hold the phone out in front of me as I walk. Instead I like to see which direction to go, then put the phone in my pocket. Then from time to time I check it to see if I’m still heading in the right direction. I imagine many users do the same.

That’s all well and good, but if it’s a really cold day you might not want to unbutton your coat, take off your glove, pull out the phone, look at the arrow, then rebutton and reglove. Or perhaps you are in a rather dodgy area of town and don’t fancy waving your expensive iPhone around. Or maybe it’s raining heavily. Whatever the reason, wouldn’t it be great if you could choose your destination, put the phone in your pocket or bag and be guided all the way there without getting it out again?

If you have a pair of headphones, now you can. When in Pocket Mode, the app will play a soft beeping sound in your headphones, somewhere between your left and right ear. If it plays in the centre (both ears), that means the target is straight ahead, so keep walking that way.

Stereo audio guidance

If you hear the sound in your left ear, the target is to your left. If it comes out the right headphone, the target is to your right. It can also be placed in stereo anywhere in between, so just walk in the direction you hear it. This covers the 180 degrees in front of you. If the target is somewhere behind you, you will hear a different beep sound, again somewhere between the left and right ear. So that covers the 180 degrees behind you, giving you a complete 360 degree coverage. With a bit of practice you should find it really easy to follow your ears all the way back to your target location. When you get within 30 metres of your target, a little beeping tune will play and the compass will turn off, so no need to take it out of your pocket when you arrive.

It’s designed to play the beeps on top of any music, podcasts or audiobooks that your phone might be playing and you have three volume levels to choose from in case you can’t hear it, or it becomes too intrusive. You can customise in Pocket Mode Settings the length of time between each beep.

The clever bit

In order for this to work in everyone’s pockets and bags, I had to come up with something to cope with all the different angles and positions people might put their phone in. The app works normally because you hold it out in front of you and the arrow points to the destination. But if you put it upright in your jacket pocket, it’s now pointing upwards and twisted 45-90 degrees away from the direction you’re facing. So any beeps guiding you would guide you somewhere to your left, when the target is straight ahead. That’s where Calibration comes in:

Each time you put it into pocket mode, you get a Calibrate button. You point the device forward, as you would normally, then press the button. It gives you a countdown of a few seconds to put the phone in your chosen pocket. It secretly recorded the angle you were holding it just then, and then takes note of the angle it now rests at in your pocket. It then works out the difference in angle between the two and offsets the audio beeps at that angle. The upshot of that is, so long as you keep the phone in that same pocket while you’re walking, the audio beeps will appear to be directly in front of you when the target is straight ahead, even though your phone is at some crazy angle.

The great thing about the iPhone compass is that is doesn’t matter if you hold if upright; the compass works exactly the same as if it were laid flat. A physical compass floating in a bubble of liquid usually doesn’t work properly if held vertically, but when I discovered the iPhone has no such restrictions I realised this new functionality would be possible.

Anyway, as with the arrow itself, sometimes the iPhone GPS can get confused and jump around a bit, throwing off the direction momentarily. The audio tones rely on the same GPS and compass that the arrow does so it may occasionally point you in the wrong direction, but it will sort itself out very quickly so if it goes off on a sudden tangent that you know is wrong, leave it for a few more beeps to see if it was just a GPS fluctuation.

Do not wander carelessly using this feature, it is important to pay attention to traffic, especially as you will have earphones in. It is for general guidance only, do not suddenly cross roads because it points you in that direction. The user takes all responsibility when using this app. Be safe.



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