Month: March 2011

Categories
Main

Exploring the Netduino #4: Make LEDs *really* Glow (or: Fun with PWM)

In our last entry, “Exploring the Netduino #3: Building the circuit on a Breadboard“, we covered the step-by-step method to wire up the proposed schematic for switching an LED on and off via a power MOSFET. In this entry, we are going to get to the fun stuff: CODE!

But first, a little bit on LEDs…

Light Emitting Diodes (LEDs) may function a lot like (incandescent) lightbulbs, but they should never be treated like them. Like lightbulbs, LEDs can be dimmed by controlling the forward voltage. Unlike light bulbs, this range tends to be rather narrow and as such is somewhat difficult to control. Fortunately, dimming LEDs can happen another way that is particularly easy to do with a digital circuit: Pulse Width Modulation (PWM).

Continue reading “Exploring the Netduino #4: Make LEDs *really* Glow (or: Fun with PWM)”
Categories
Main

Exploring the Netduino #3: Building the Circuit on a Breadboard

In “Exploring the Netduino #2: (Indirectly) Driving an LED“, we covered the electronic theory of how to use a Power MOSFET to turn the LED On and Off via a digital signal. In this post, we are going to walk the reader step-by-step on how to wire-up the circuit on a breadboard. If you’re using an Arduino, the steps are exactly the same.

As mentioned previously, you will need the following equipment and parts:

  • An electronic breadboard
  • A few common LEDs (like 5mm Red)
  • A couple resistors (a 1 MOhm and a 68 or 100 ohm)
  • N-Channel MOSFET (like RFP30N06LE)
  • A 3.3v power supply or a 2-cell AA Alkaline battery pack (3v)
  • Some jumper wires to connect the circuit together
  • Multi-meter (optional)
  • And a Netduino or Arduino, of course!
Continue reading “Exploring the Netduino #3: Building the Circuit on a Breadboard”
Categories
Main

Exploring the Netduino #2: (Indirectly) Driving an LED

In “Exploring the Netduino #1“, you may recall that it was suggested that the reader take a look at the Netduino “Getting Starting” guide found on the Netduino.com site to get a feel for the hardware. The guide walks the user through a “Hello, World” equivalent where the  user ends up getting the blue on-board LED to blink on and off. This tutorial aims to pickup where that guide left off.

Over the next few posts, we will cover how to wire up an LED to control its brightness using the Netduino’s Pulse-Width Modulation (PWM) features and supporting electronic circuitry.

Continue reading “Exploring the Netduino #2: (Indirectly) Driving an LED”