PComp Labs Week 2 – The Start of it All.

I have a tiny bit of experience with electronics and arduinos.  In fact, I actually took an electronics class as a sophomore physics major – and I learned ALL of this stuff.  But that was, jeez, 7 years ago?  Suffice to say I’ve forgotten pretty much everything I learned.  I do remember my final project for that class – I made a simple guitar tuner that would take audio input from a cheap mic and light up a certain LED if the frequency of the input matched the frequency of an open string.  I learned all about circuits – Krichoff’s law, Ohm’s law, Gauss’s law and some basic examples of Maxwell’s equations (even though that stuff was covered in much more depth in a different class that wasn’t applied, but purely theoretical).  Anyway, this super basic stuff was pretty straightforward, but it was good to spend some time measuring and confirming that my understanding of electricity was still intact.

IMG_3568 2

The “Hello World” of electronics.


LED’s in parallel!


LED’s in series

IMG_3573.MOV – Potentiometer in action

IMG_3575.MOV – Moving a motor using Vin and tapping the 12V supply by which I was powering the Arduino.

IMG_3576.MOV – Playing with a photoresistor


Lastly, some practice drawing out the circuits and measuring voltages.  Everything was as expected, as voltages would drop across components and add up to 5V (my input voltage).  Things get a bit strange when wired in parallel, but remembering the rule of thumb that objects in parallel drop in current, while objects in series drop in voltage explained that.  Parallel is beneficial when you need the same voltage applied across several components.  I was a bit thrown off by the legs of the potentiometer, as I couldn’t find specs for the exact one I had, and wasn’t sure which leg was which, but I think I got it right since it all worked out.  It was interesting measuring the potential difference across the various legs and starting to understand how it divides voltage.


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