Capacitive audio feedback design tool

An open assignment for an interesting course I followed had the goal of creating a new novel design tool with audio feedback.

For this I created a capacitive sensor. This sensor consists of a wire sticking straight up. The principle of a capacitive sensor works by being one half of a capacitor. Your hand or anything else that can store capacitance is the other half of the capacitor.

The capacitiveSensor method toggles a microcontroller send pin to a new state and then waits for the receive pin to change to the same state as the send pin. A variable is incremented inside a while loop to time the receive pin’s state change. The method then reports the variable’s value, which is in arbitrary units.

This measured value is sent to the computer where software written in processing uses this value for display purposes. As a visualization a constantly updating stack of circles is used. This gives the impression of a tube. A new circle is drawn with the measured value of the sensor. Also an tone is played based on this value. This makes it a rudimentary theremin. The audio feedback gives extra depth to moving your hand around the sensor and gives the user directly a better understanding of how his actions change the visualization.

Salvaged Linear Actuator

From an old HP ink jet printer I salvaged a linear actuator assembly. This assembly consists of a DC motor, sliding rods, a carriage, toothed belt connected to the carriage and an optical linear encoder with the corresponding sensor on the carriage.
The sensor on the carriage is connected to the interrupts of the arduino, so no pulse is missed. By keeping track of the pulses the carriage knows where it is.

A H bridge motor controller is used to actuate the DC motor, this moves the carriage.
A simple control loop was made to have the carriage more back to a set point on the actuator.

RGB ledstrip music visualizer

Music visualizations have always interested me. After getting an RGB led strip to work I wrote some interesting software that translates music on the fly into RGB color values.
The software listens to all the sound produced by the PC, so any music software is compatible. The software performs an fast Fourier transformation on the audio and displays the resulting intensity spectrum. I can then device a band to be used as the intensity value for the light. Different songs have different areas in the spectrum as the most dynamic. With this software I can select the most dynamic or interesting part of the intensity spectrum on the fly. It is also possible to set threshold and multiplier values, and to select a color for the lights. This results in a responsive and easy to use compatible with anything RGB LED music visualizer.

Programmable Pattern for NeoPixel RGB LEDs

In this video I show the details of how my pattern programmer for the NeoPixels work.
This little project is a continuation of the leds I used on the chaotic pendulum.
With the software you can draw patterns by hand or load up an image. The software programs the values to the arduino’s EEPROM, this means the device can be disconnected and powered down, while still preserving the pattern. After programming no PC is required anymore.

I used this little installation with great success as a quick way to add interesting RGB light effect to clothing on Makerfaires.

Chaotic Pendulum with programmable RGB LEDs.

For my bachelor project I have created a technical art installation. The exact course of the project was not a smooth one and I won’t go into the details how we arrived at this prototype, but I will describe what we ended up with.

The device is a double pendulum constructed out of laser cut plywood. A double pendulum exhibits chaotic behavior.

Animated gif of a double pendulum

The device features bearings for smooth rotation and a wireless power transfer system. The wireless power transfer system at the joint makes batteries not required at the end of the pendulum. Batteries would make the pendulum very heavy and swing around much less. The following album shows the design of the power system in the free rotating join.

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The following pictures show the complete construction of the prototype and its components.

The pendulum can be cranked up with a ratchet wheel system. When ready the pendulum is released and swings in a chaotic fashion. The lights on the device are programmable in software on a PC.
With this setup great long exposure pictures can be taken. The chaotic nature of the motion in combination with the fixed patterns creates very interesting images, the following album shows several different patterns being displayed by the device.

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Details of how the RGB leds are programmed are in a seperate post.