In case you hadn't already seen it I've posted a new article (http://andybrown.me.uk/2016/02/21/nanocounter/) over in the main website that documents my frequency counter project. There's also a video (https://youtu.be/c8_JnJcHIVg) on youtube. My frequency counter combines an FPGA to do the fast counting with an STM32 to do the controlling and an android app to do the display work.
(http://andybrown.me.uk/wp-content/images/nanocounter/built.jpg)
Schematics, gerbers and all the source code are of course free and open source.
(http://andybrown.me.uk/wp-content/images/nanocounter/app_running.jpg)
I've now released version 2 of the Android app that fixes a few bugs and adds some new features. Anyone who's installed it should receive an update notification from the Play Store. The list of new features and bug fixes can be found here (https://github.com/andysworkshop/nanocounter/issues?q=milestone%3A1.0.1) on Github.
I've now built a case for Nanocounter. Well, it's more of a shield than a case but it does the job of protecting it from knocks and drops. Check out the article here (http://andybrown.me.uk/2016/06/11/nanocounter-case).
(http://andybrown.me.uk/wp-content/images//nanocounter/case/assembled.jpg)