Cadence app for Android - no pickup required
 

I don't know how useful this will be, but I have been developing a Cadence app for Android that does not use any external cadence sensors. It works with the built-in tilt sensors in the phone itself. All you need to do is have the phone in your pocket. As you pedal, the slight movement of your leg is enough to be detected by those sensors. The calculated RPM is announced by text-to-speech conversion so you might hear it from your pocket if it is not too noisy. If anyone would like to test it out to see how it works, I have attached a ZIP file containing and APK file that can be side-loaded on an Android device. Eventually I may put it in the Play Store once it is fleshed out into a full-featured cadence app, but right now it just does one thing - calculate and announce RPM. The cadence range is about 45 to around 200. It requires a steady cadence, so if the movement is unstable, it will just not report anything.

As I said, the app is quite primitive at the moment, and will need lots of refinement, but I thought it might be fun to see what users thought of it and what direction I should take with it. For example, I could implement logging of RPM for later review. Or, to get a visual display, I could use Bluetooth to communicate with a second phone mounted where the user could see it. In that case, my app would take the place of an external sensor. But that would be an expense because now you would need two phones (unless you have an old one lying around.) As you can see, I don't really know what to do with this app. I developed it just for fun to see if it would be possible to extract RPM from the slight movements of a device in the users's pocket.

Oops, I replied to your other post but this is the more appropriate thread. There should be some intersection on the Venn diagram of "cyclists interested in sensor-free cadence" and "cyclists not wearing traditional bike shorts and bibs - thus possessing pockets on legs" but I wonder how much?

Reviving old thread...

Is this the current iteration of the app the OP started developing? : Cadence - Run and Bike Tracker App for iPhone and Android

If so, the app is quite impressive. After watching a few YouTube reviews of the app, it looks like a great alternative to having a dedicated cycling computer provided one's various devices are Bluetooth compatible (which most are). The only thing that's prevent me from trying it as a replacement for my Garmin 830 is that the Cadence app can't connect to electronic group sets like Shimano Di2 or SRAM eTap. I'm assuming Garmin must've paid Shimano a licensing fee to interact with Di2, of which I like it that I can see my gear shifts on my Garmin and it beeps when I'm about to do a front derailleur shift.

For those that are on mechanical group sets, the Cadence app sure does look like a really good alternative to a dedicated cycling computer.

No, this is not my app. Although the technology of using the built-in accelerometers in the phone did work for sensing cadence when the phone is in your pocket, it is very hard to hear the spoken feedback from your pocket over the trail noise. So I have abandoned my project.