Your circuit will ultimately include 3 LEDs and a slide potentiometer. It should look something like this:
I would develop this on your breadboards first, and then solder things together in your sweet, sweet cardboard box.
The LEDs should be connected up to PWM pins. I used 560Ω resistors in series with the LED.
Your slider has four connection points, one of which is actually "dead," or unconnected. The two connections that are fully connected should go between +5V and GND. The remaining connection (which is where we read the value of the slider) should go into an "Analog In" pin on the Freeduino—one of the analog pins 0 through 5.
Fritzing, the tool I use for building diagrams, does not yet have a slider. Hence, I used a sticky note. (Fritzing is an open source project aiming to build a circuit design tool "for the rest of us." For a Comp Sci student interested in circuit design, this might be a really great tool to explore. Certainly, I'm enjoying using it.)
QUESTIONS
- Why do we put a resistor in series with the LED?
- What is the minimum resistance value we need to include if the maximum forward current of our LEDs is 30mA?
- Use a multimeter to determine the maximum and minimum resistance of our linear slide potentiometer (fancy word for "slider").
