Tag Archives: labs

Transistor Lab and Motor

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Here is some documentation of the Transistor lab.

I had to do it twice.  My first try was at the end of a long day and it did not work.  However after talking to some friends, some hard thinking, and a good night’s rest, I realized the mistake I made.

 

It may be hard to see but I accidentally soldered my voltage adapter in a confusing way.  The Black wire is the power and the Red wire is the ground. :(

Not the worst mistake but if there is a way to re-solder this I think I would like to do that.

Once I realized this mistake, I wired the transistor and motor as the lab instructed.  And while trying to document I felt like the motor spin would not be visible so i added a twist-tie.

More limitations:  I did not think ahead of time to give the motor some longer wires.  So the twist tie acted like a weed-wacker against my hand.  The quick fix was to add a piece of paper.

For me this paper was a beautiful accident.  It started making me think about persistance of vision and animation. Maybe I can use this technique (or some variation of it) in a future project.

Multiple Serial Communications / First Stretch Sensor Test

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The setup:

Once again I did not have all the parts (accelerometer) for the lab so i had to make due with the kit switch, potentiometer, and an FSR:

Sorry if it is hard to see….

It took me some time for the principles of serial communication to set in.  But after a few errors I eventually got both the “handshake” and the “comma separation” methods to communicate with the Processing Sketch.  (Videos are all screen grabs from my slow computer so some of them are glitchy).

I also later on used these sketches to test out some stretch sensor values to check its range and responsiveness.

It was pretty responsive but the range is slightly unpredictable, but mapping the vaules to the size of the sketch gave it a sense of stability.  I do not yet know how this will affect our musical midterm.

 

Tone documentation

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Here is more documentation from the tone labs.  I’m getting better at remembering the Arduino syntax so it didn’t take as long to troubleshoot this time.  I also got my hands on the correct  resistor (100 Ohm) for the speaker so now the sound is actually audible:

Here is a tone from two photocells in series acting as a variable resistor:

Here is the “3 note instrument” part of the lab.  I did not have three FSRs so for “keys” instead i have an FSR, the kit potentiometer, and two photocells in series acting as a variable resistor.

On my first try I got a continuous tone from the start and I did not understand why.

Then i realized that the threshold function was too low.  The lab told us to set it to 10, but after taking readings from all three “keys” I realized that the photocells read in the middle of their range when neither cell is covered.  So even though their range is from like 80 – 900, if there is no difference between the two they will stay between 450-600 (depending on the room). So I boosted the threshold to like 620 and the instrument was silent until i activated one or more of the sensors.  Here are two videos of that: