For this year’s RedBull Creation competition, we had to incorporate a ‘Bullduino’ into the project of our choice. What is a Bullduino? It’s essentially an Arduino Uno shaped like the RedBull logo. So, we came up with the idea of creating a Telepresence Zen Garden. Sounds simple right? Well, it was actually more difficult than it sounds.
The diagram below shows you from a high level what we did. We created a user interface in Flash which allows the user to draw lines on a canvas. That data is uploaded to a web server and stored into a MySQL database. There is a queuing system written in PHP on the web server. The queuing system keeps track of the order in which the drawings are submitted and it is responsible for keeping the buffer full on the Bullduino. The connection between the web server and the Bullduino is a TCP socket which is forwarded to the USB-to-Serial connection on the Bullduino.
The linux laptop is running 2 things. It’s running socat which does the TCP to Serial forwarding and the Flash media encoder which streams a video feed back to justin.tv.
The Bullduino is connected to a rail of power mosfets to control turning on and off 8 banks of Red and Blue LEDs. It is also connected to 2 stepper motor drivers, 2 servos, and 4 limit switches. The limit switches are used to zero out the XY table and prevent damage to the machine should something go wrong.
One of the servos is responsible for raising and lowering the drawing pen. The other is responsible for raising and lowering the eraser bar. Here is a little video showing how the eraser bar works.
The entire system is powered by a modified ATX power supply which provides 12V for the stepper motors and 5V for everything else. The construction of the Zen Garden was a combination of hand cut MDF, laser cut wood and 3D printed brackets and pulleys.
Finding the right sand was critical. A very fine grain sand provided the best detail. We settled on using 20lbs of Nature’s Ocean Premium White Sand from Petco. We experimented with different grain sizes and even mixed the smallest grain size with the larger grain sizes but this did not provide the detailed land and peaks that the Nature’s Ocean sand provided.
Note to self: sifting sand through a Mexican hat is not fun. Be sure to buy extra sand for experimentation.