Tzedakah Box II
The Tzedakah Box II is an interactive sculpture created by Craig Harris and Candy Kuehn. I designed and built the electronics to interact with Ableton Live using the Midi protocol on an arduino. The sculpture makes use of four buttons, two distance sensors, and one PIR motion sensor.
The sculpture was a part of the uncommon visions exhibition and was open May 15 – June 23, 2011 at the Tychman Shapiro Gallery, Minneapolis, MN.
The buttons are modified led battery operated lights. They have been modified to operate off of the arduino 5volt power instead of the typical 6 volt that the batteries would have provided. Three wires extend from the outside of the buttons, they are the power (red), ground (blue) and data (white). Once inside the Tzedakah Box they are color coded (blue,white,green,and clear (no color code)). One color code for each button.
The wires end in a crimp on snap connector, these can be found at Home Depot or Radio Shack. Once there they run into the control box. Inside the box they are soldered to a Adafruit protoshield. The power runs through a 220 ohm resistor to limit the current to the leds so they aren’t so bright. The collections are as show in the Data Table.
The distance sensors are of the type MaxSonar EZ1. They are connected via a ribbon cable, and terminate via a crimp on snap connector like the buttons.
The motion connector is Radio Shack Catalog #:276-033. It is connected similarly to the buttons.
Throughout the whole system blue is ground, red is power and white is data.
The Arduino Program
If the PIR sensor detects motion the system will start working by sending a midi note to the system, at this time it also starts a 600 second or 10 minute timer. If no motion has been detected in 10 minutes the system will send a midi note off and the Tzedakah Box will go silent.
Each on of the buttons triggers a midi note on and a midi note off once they are pushed.
The distance sensors are calibrated to send 0-127 control change midi values, these values are mapped to a distance from the sensor of 0 at about 3 inches away and 127 at about 12 inches or so from the sensor. If the sensors are “seeing” anything in this distance range a on message is sent and the output value is mapped to midi control change value 127. If a 127 value is seen for 10 seconds or more the sensor times out and sends an off message.
There is a standard midi connection on one side of the box, this is connected to pin 1.
There are 2 programs, the first is to help Ableton map the midi messages, this one is called midi map. It sends a midi signal every 4 seconds in an endless loop. Change the variable to change what the arduino is sending.
The second is the full program, this is called Tzedakah_Box_II.