i-rant

Pinewood Derby Time!

Daniel is looking to have some fun with his Pinewood Derby car this year. He wants to make a spaceship with blinking lights; or even continuously glowing lights.  We went to Fry’s Electronics to see if we could get some things to do this and I learned from an interesting guy in the isle buying LED’s and Resistors that this would be no easy task.

I tried to talk Daniel into a simple circuit with an incandescent light. “you mean a flashlight” and I said “pretty much.” Daniel is 10 but he is as cynical as a crusty old man.  So I’m searching the web trying to learn about these things. 

While we were at the store we picked up a pack of LED’s, a Resistor, a battery holder and a bunch of wires.  I also picked up a book on introductory electronics.  I don’t have the physics or electrical engineering background to know all the math; this is going to be tough.  The cool thing for me is that DJ was interested and basically understanding what the guy at the store was saying.  He will obviously do better then I did in calculus and physics when the time comes. 

So I found this basic Tutorial for LED’s and Transistors and another tutorial on Basic Electrical Components. I am getting the basic idea that you don’t want to blow up the LED’s with too much power so you have to regulate it. Resisters help do that, measured in Ohms.  Diodes are one-way components with the current running through them when the voltage on the positive leg is higher then the voltage on the negative side. Put a battery in there and you got power. Use a resister to regulate the flow so you don’t blow up the Diode. The website said usually when current is flowing through a diode, the voltage on the positive leg is 0.65 volts higher than on the negative leg.  How do I get from Volts to Ohms?

That same sight has a Tutorial for learning about Ohm’s Law

Wikipedia: Ohm’s law states that, in an electrical circuit, the current passing through a conductor, from one terminal point on the conductor to another terminal point on the conductor, is directly proportional to the potential difference (i.e. voltage drop or voltage) across the two terminal points and inversely proportional to the resistance of the conductor between the two terminal points.  I – V/R,  where I is the current, V is the potential difference, and R is a constant called the resistance. The potential difference is also known as the voltage drop, and is sometimes denoted by E or U instead of V.

There are ways to try this out.  We will probably get a Breadboard to plug a bunch of this into to create our circuit.  I have to learn how to do this math and then get the thing going.  To put it on his car, however, will be the real challenge.  Perhaps we can splice it all together and then tape it on the car; painting over the whole thing.  If I can create an LED circuit with enough power from only one AAA battery then we can hide it, maybe two batteries. I imagine the weight will be offset by how much we hollow out the body to put these batteries in there.