... Visual Metronome ...

I had many ideas for the final project but was constrained by the need to use a variety of the fab techniques we've learned this year as well as by the need for it to be feasible. My idea to make a visual metronome was inspired by my experiences as a musician playing in a chamber music group this semester. We were practicing with a metronome and were having difficulty following the beat. Old-school windup metronomes employ a pendulum to produce the clicking noise that musicians use to keep their tempo. An added benefit is of course the visual cue of the pendulum going back and forth.

Somehow, this most useful feature has been lost in most metronomes today--they are electronic, and have only wimpy LEDs or dim LCD screens, or no visual display at all. We sacrifice functionality for the convenience of carrying around the metronomes in our bookbags.

Musicians have highly developed peripheral vision both from being used to watching their fellow musicians as well as following a conductor and that white baton. During our chamber group rehearsals, I found that we had a better time keeping time when our chamber coach clapped than when we were following an electronic metronome. I do not think this is because of volume, because if anything, the electronic metronome was louder than the clapping of our coach. My theory is that our chamber coach's arm movements provided an extra visual cue to aid our music playing, just like a conductor. So why are there no large-scale metronomes with moving parts that not only provide musicians with an audio tick, but also provide visual cues?

Besides the aforementioned visual display, the Visual Metronome also has several other advantages.

Most music is generally cyclical in the rhythmic sense, with one period being the measure. Why not then represent this unit cell, the measure, as a circle or a wheel? My hope is that this visualization is highly intuitive and will also serve as a pedagogical tool, allowing musicians to easily visualize such rhythms like 4 against 3 using the two wheels. This is, of course, why I chose 12 as the number of spokes around the wheels.



Last but not least, I would like the Visual Metronome to be aesthetically beautiful and to be as much sculptural as it is functional, just like well-designed furniture. Yeeah. Obviously I'm aiming high.

This is a rough sketch of the final design.



Here are some drawings of the general system.



Below are sketches of what the circuit board will eventually look like.



Shown below is a materials list as well as a sketch of the wheel design.



I laid out my boards in eagle and milled them on the modela. The boards below, from left to right, are:
1. Tempo Board: this board takes input from the potentiometer and sends out a square wave whose frequency depends on that input.
2. Motor Control Board: this board takes in 12V and the square wave from the Tempo Board and moves the motor.
3. Input/Output Board: this board will sense the spoke going by and output light and sound.



Parts that I have already ordered and received:




I've blown up so many boards!
All of my boards are extremely unstable and I am unsure why this is. They will work one second and not work the next.
Yes, it was an integration issue.

The code for each of my boards worked fine on its own.
1. The Tempo Board: this board reads in input from a potentiometer and outputs a square wave. The frequency of the square wave depends on the potentiometer.
2. The Motorcontrol Board: this board reads in the square wave from the tempo board and uses this wave to control the motor steps. The speed of the motor is thus dependent on the frequency of the square wave.
This board went through many iterations. I changed the charging cycle to be smoother, but then when I added the wheels I realized that the motor needed more torque in order to turn so I had to change the code yet again to maximize this.
3. The Input/Output Board: this board senses the magnet on the spokes and outputs light and sound. Additionally, a toggle switch allows the user to choose the tone.

Here are links to the code I used.

... Motorcontrol ... 3-D model

I cut the wheels out of acrylic.
The panel is made from wood that I stained.
The spokes are sandblasted acrylic with press-fit magnets.





Movie of spinning wheels

Movie of working sensor



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