Domo Domo

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This experiment was the longest yet.  The goal here is to build up a circuit that makes a pulsating style noise, like a burglar alarm.  In the process I learned about programmable unijunction transistors (PUTs), and how to use bipolar transistors (in this case the 2N2222) to amplify a signal.

Making some notes to myself here about PUTs, as this is the major new component introduced in this experiment.   The most common PUT is model 2N6027.

Like a bipolar transistor, a PUT has three leads.  However, they are called the anode (input), gate, and cathode (output).  The lead orientation of a PUT is opposite of a 2N2222.  So if you have the flat side facing left and the round side facing right, this will put the anode at the top and cathode at the bottom.

There are two main differences between a PUT and a bipolar transistor. Read the rest of this entry »

My startegy for learning stuff by lonesome is triangulation.  When you are book learnin, often times there will be gaps in one author’s explanation.  By getting two or three books that cover the same material, you can can use your secondary books to backup your ‘main’ book.

Make: Electronics is still my main book.  But now I got the classic Getting Started in Electronics too.  Also picked up Electronics for Dummies.  I’ve already run into a few things I was spotty on.  For instance, with a unijunction transistor, I get that you program it’s voltage tipping point via a resistor.  But what I don’t get is how you know what that point is.  Hoping that when I run into these kinds of situations, the other books will help me out.

I’d like to see a video game leader board website.  It should have a super simple API.  Anyone game can submit to it once the developer has an API key.  It would not be tied to any particular game engine, totally neutral.

Each leader board would have an RSS feed that can be used be rebroadcast that data on other sites/within a game itself.  It would be nice if there was a way for people to ‘claim’ their scores somehow, so they all show under one unified account.  Not sure how this might work.  Maybe facebook connect/oauth is part of the puzzle.

XBox Live certainly has this concept, but it’s an island (a really big, totally awesome island).  But what about random flash games, iPhone games, etc.

There might be some sites out there doing this, but they seem to be tied to specific platform or engines.

Resistors have a color code that tells you how many ohms of resistance they offer.  This site quizzes your memorization of the codes.

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I’ve wired up Experiment 10 from the book Make:  Electronics by Charles Platt.

I show a couple of things in this video.  First off, I’m using an NPN style transistor to switch complete the circuit to an LED.  A NPN transistor has three leads: a collector, a base, and an emitter.  When the base receives current it enters a switched state, which connects the collector and and emitter leads.  The collector is positive and the emitter is negative (this is reversed for a PNP transistor).

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I’ve wired up Experiment 9 from the book Make:  Electronics by Charles Platt.

This experiment shows you can use use a resistor and a capacitor to create a timer.  The multimeter on the left measures voltage.  As I swap in a 100K resistor, a 47K resistor, and a 10K resistor, the charge up time gets faster and faster.  In other words, the less resistance in the circuit, the “quicker” the flow of current to the capacitor, and the faster it charges up.

I’m using the push button in this experiment to complete the circuit, that way it’s not always going while I swap out resistors.

Garage doors are a big deal when a mistaken open means precious seconds waiting in the sub zero outdoors.

Current problems with my garage door…

• I don’t know if the doors open or closed.  I have no line of sight, so I often close the door when it’s open, or am uncertain if I had really opened it.
• My remote sucks and sometimes the signal is too weak to open the garage door, and I have to walk outside to do it.
• Sometimes I just plain forget after I’ve already walked outside and left the remote locked in the house.

Once I get better at this electronics thing, I’d like to setup a rig that:

• Opens or closes the garage door via an iPhone formatted web page
• Checks the current open/close status of the door and posts that to the web page

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The same circuit as this one, but breadboardified.  Finally (nearly) free of alligator clips.