I gotta say, if you go to some of the better karaoke joints in the city, you really see some pretty straightforward physical computing stuff there that's done very effectively. At the place I was at last night, there were LED tambourines, lights that dim and shone with the baseline, all kinds of stuff. So, let me say it here first -- KARAOKE COLLAB! Because it's time, people. It's time.

Arduino Light Meter: Ye olde digitalWrites and analogRead at work.Here's an example of something simple and (potentially) practical you can make with an Arduino: a light meter!

The trick for me, if you look at the photo, was to use a voltage divider for the photoresistor. That is, the analog input comes from the point on the circuit between the photoresistor and a 1K ohm resistor.

Ye olde digitalWrites and analogRead at work.

The Arduino coding session we had today seemed to go pretty well (though I'll let the other folks blog about what it was like on the student end of things.) We got a bunch of things blinking and buzzing, and we covered most of what you need to do to read and write digitally and analog... analogally... analogly... analogalogally... hmm, don't know the word for that. At any rate, it was fun for me.

• shiftOut
• turns numbers into streams of data
• handy for working with other chips
• especially simple ones that don't take serial

Buzzy BasicsOkay, actually, that's a pot as in potentiometer. Nyuk, nyuk. Anyway, let have some fun here!

• Connect pot to analog in pin

• Analog pins don't require pinMode -- they are fixed

• analog read pins are on a separate set up pins

• analogue write pins (PWM pins) are on 9, 10, and 11

• analogWrite takes a pin and a value (but the value must be between 0 and 255)

Knight LightsNow let's put some of this stuff together into a new circuit. You'll need four LEDs, four 220 ohm or 470 ohm resistors, one 1K ohm resistor, a push button, and a bunch of wires.

Hook four wires into the Arduino's digital outputs (check the code to see which ones.) Connect the smaller resistors to each of those wires, then connect an LED to each resistor with its short leg to ground. Be sure to hook up the 5V and GND lines between your Arduino and breadboard.