Media Controller – Week #3

When we started talking to people about this project, namely that we wanted to translate the voltage signal coming off cassette tape into light, the name Eric Rosenthal kept coming up as someone “we should talk to.” Eric Rosenthal is ITP’s resident electronics guru. Just as Tom Igoe is an expert in all things Arduino, Eric Rosenthal is the master at all things analog. He teaches a class (that I really want to take) called Basic Analog Circuits. He basically knows anything you’d want to know about electronics.

So, we went to him to try and figure out the best way to read the signal coming off the tapehead, and translate it into light. After hearing our concept, Eric proposed an analog method to achieve what we wanted. We were really excited about this, mostly since the concept behind the project is a sort of ode to analog technologies that have been (or will soon be) retired. However, after thinking about the project a bit more, we opted to use the Arduino since it will afford us more control in mapping the input signal we get from the tapehead.

In order to preserve the signal coming out of the hacked Walkman, Eric recommended we get an 1/8″ stereo jack, which splits the signal from the ground. He also helped us design a circuit to preserve the signal, which connects one of the stereo signals to a 104 capacitor and signal diode in parallel. I’m not completely sure what they do, but I think it maintains the signal strength without actually amplifying it with an op amp, which is what we thought we had to do originally.

signal input and light output circuit

We split the signal coming out of the Walkman line out jack with a Y-splitter. One 1/8″ cable goes directly to our speaker for the audio output, and the other 1/8″ cable goes to the stereo jack, then to the signal diode / capacitor circuit, then into the Arduino. Our Arduino program then maps the input to an LED connected to a PWM pin, so that it gets brighter and dimmer according to the voltage signal.

This week we also heard about the NIME conference, which had a call for projects for a museum exhibition that would coincide with the conference and performances. We decided to enter our Media Controller as an exhibit, which was due on Friday, November 5th. It was an interesting process trying to write about the project before we had completely finished making the conceptual and formal decisions, but it also made us put down on paper what we wanted it to do, and the significance behind it. Here’s crossing our fingers we get to go to Norway!