Tom Hoddes

Free Online Guitar Tuner built with HTML 5 Web Audio API

Wed, 19 Feb 2014 16:52:57 -0800

I've been playing around with the new Web Audio API features and have completed my first web app.

As far as I can tell, it's the first of its kind, an in-browser Guitar Tuner that uses the microphone and no flash whatsoever.

Hope you find it useful and/or cool: freetuner.co

Note that only firefox and chrome are supported.

An Open Source View for Real-Time Graphing in iOS

Wed, 12 Dec 2012 17:36:58 -0800

Today I open sourced a simple UIView subclass for iOS that I've been using in an upcoming Guitar Tuner - Chromatic rewrite/update.

It simply takes in y values of a graph and updates very fast. Fast enough to use in real-time multi-threaded graphing applications.

Here it is on git: https://github.com/hoddez/THGraphView

Statistical Significance For $10

Tue, 19 Jun 2012 01:19:04 -0700

So I've been toiling away on a new app icon for my guitar tuner and I figured I'd better test it against the old one before I go any further with the overall design of my app.

For some time now I've been known to suggest that people AB test their app names and icons using admob. However, until now I've been quite the hypocrite, having never done this myself mostly out of a combination of laziness, cheapness, and not having any other icons to test.

So I started an admob campaign with icon_old and icon_new ads and the same tag line in each. I decided to start with only $10 worth of clicks and if I didn't have statistical significance i would slowly add more until I got it. After a few minutes my $10 had been used up and I had gone through about 125,000 impressions per ad with 0.43 CTR for the icon_new and 0.36 CTR for the icon_old. If you do the math this equates to a significance level of 99.74% which even the most cautious would call significant.

I've been wondering how much it costs to get statistical significance using admob AB tests and now I know a ballpark. In this case statistical significance costs less than $10.

vDSP Accelerate FFT Made Easy

Sun, 12 Feb 2012 19:33:37 -0800

In iOS 4.0, Apple opened access to the vDSP library on iOS which has some nice DSP functions (FFT, Convolution, etc.). I've been using this library for some time now in my apps.

I've had a few people ask me if it's "easy to use."

It's not too bad and the documentation is there if you know where to look, but initially it can take some time to work out what format the data should go in/out as depending on you're intended use.

Today I've released some of the code I've written to interact with this library at a high level. If you just want to do a straight Real FFT, this may save you some time figuring out the vDSP library.

I plan on adding other features if the demand is there. So if you use it or would like to request features please let me know.

The Code is available in a sample project on Github

Enjoy!

- Tom
tom@tomhoddes.com