Over the past few months, I digged more deeply into the Arduino platform. One ongoing project is a clock with moon phase display (since I already implemented the computations for my astronomy app, Cor Leonis). I started out with an LED matrix and 7-segment displays like this:

Tons of wire!

Over time, I decided to use 2 8x8 LED matrices, switched to a smaller Arduino compatible board (Adafruit Pro Trinket), and ran it on batteries:

There's also a button to switch between views now.

It's far from done, but I find it amazing how much I already learned from this relatively simple project... a refresher on basic electronics (resistors, capacitors, etc.) and soldering,  manual LED matrix display multiplexing, more on LEDs than I ever wanted to know, RTC clock chips, LED display driver chips, shift registers, step-up/down voltage converters, debouncing HW buttons, I2C bus wiring and communications, calculating power consumption and battery lifetime, and so on and so forth. Next up is sensors: I would like to switch views just by waving my hand (and see how robust that is), instead of having to walk over and press a button.

 

When I was thinking about how to put the moon into the 3D view of my astronomy app, I figured it would be a waste to actually display a textured sphere. After all, we always see the same side of the moon. All that is needed is a textured quad, and a shader which emulates a lit sphere. In the end, the quad was reduced to a single vertex - a point sprite. Try it out in the Demos section: WebGL moon shader

After a looooong break, I picked up development on my astronomy app, Cor Leonis, again. The latest version 5.0 is available now for iOS devices in the Apple App Store. The one big feature which justifies the major version jump: the moon! While I was working on the moon info panel, I also beefed up information about the planets in our solar system a lot. Hope you like it!

Added a new entry in the Demo section, showing how to do articulated figures in processing. Check it out: Articulated Structures Animation