I always want to add "made list of things I made"

in Today I Made

note: while I was working on this post I decided to schedule it for tomorrow morning since I’d just posted the capstone thing. And then I spent an hour writing about arduino problems and decided people could just deal with having more than one post from me show up at a time, but once I’ve “scheduled” a post in wordpress rather than publishing it immediately, I don’t seem to be able to switch back to immediate publishing. And I guess wordpress’s clock is not set to the same time as me, because I scheduled it for two minutes in the future and it didn’t show up. Of course I can’t find a way to discover what time the scheduler thinks it is. So…whenever this post gets published, it will be more than a few hours after I finished writing it. I mention it because, you know, interaction design blog, and this was definitely an unnecessarily irritating interaction..

The making of things continues!

I’m doing some testing with my independent study prototype this evening (which is basically a project branching off my main capstone work), while I’m here doing work on my computer, and I keep having to mess with it. The tricolor LEDs I’m using seem to work differently when powered by a 9-volt battery than when via USB cable into my computer. I assume this has something to do with the greater…current or power or whatever from the battery, but I don’t understand why. I clearly do not know enough about electricity.

Did I mention that my book helpfully goes over very basic programming concepts but then just presents me with circuit diagrams and assumes I will know how to make sense of them? That is not a safe assumption. I’m still checking my notes every time I make a change to make sure I’ve got the right end of the LED connected to the right part of the Arduino. And five minutes after I’ve looked it up I’ve forgotten which leg is the positive terminal and which is the negative. I can at least consistently remember that the negative terminal should connect to ground. I like resistors because I just put them somewhere in series in the circuit and directionality doesn’t matter. Simple! Also they are cute and colorful.

I know the arduino is built to shut itself down in case of possible short circuits or overloads, so maybe the increased current from the battery is overloading my LEDs. The way the tricolor LEDs work is that it’s a single piece with four legs, one to attach to the power supply and one for each color to connect to ground, or in this case an arduino output pin. For my current application I’ve got all three colors connected to a single output pin, because I just want to turn bright while LEDs on and off, and these are brighter than my single-color white LEDs. But each leg is connected to the output in parallel with a different resistor, and the reds are connected through a higher-value resistor than the other two colors (the instructions on adafruit told me to). My first sign of trouble was when the LEDs started turning red instead of white, so maybe the blue and green components were being overloaded, not having the extra protection of the higher resistance. Then when I hit the buttons that are supposed to turn the LEDs on, I can turn on one but if I try to turn the other on too they both go out.

Anyway I guess tomorrow I’ll try switching to higher-value resistors and see if that works better, I’m too tired to keep fiddling tonight. I do wish I had something between 100 Ohms (the resistors connected to the red components) and 330 Ohms, the next largest resistor value I have. I want these LEDs to be as bright as possible.

Oof, enough rambling about things no one else will read anyway.