Open source
Xtendroid
Xtendroid is a domain-specific-language for Android that I created for productive Android development
Raspberry Pi Star Trek LCARS Interface
Star Trek LCARS interface implemented on a Raspberry Pi with touch screen, using Python and pygame
PiScope
PiScope is a House4Hack project, presented at ScopeX 2015, to do basic astrophotography using a RaspberryPi, Arduino, 3d-printed parts, and a telescope.
Gym Timer
I built a dead-simple Arduino-based gym timer for my StrongLifts 5x5 routine
BatteryFu battery saver Android app
BatteryFu is an Android application I wrote to save battery life (and data) on my HTC Dream (G1) back in 2010. It has over 250,000 downloads!
House4Hack SHAC on BlackBerry 10
House4Hack Smart House Access Control app lets you open the gate and front door at the House4Hack hackerspace in Centurion, South Africa, once authorised.
BluMote
I won the MOMO Joburg "Changing the world through innovation" competition, as well as the Mobile Web Africa 2012 app competition, with the BluMote project!
MakerDroid
MakerDroid (previously Paint3d) is an app you can use to draw out a 2D shape that will then get extruded into a 3D shape, which you can then print out as a physical object using a 3D printer.
DroidOrb
I built an Android accessory using an Arduino. It's a charging dock and notification light, among other things.