I tried very hard to put links to all the images I got from the internet. If I missed any reference, please let me know.

Electronic circuit design and component selection

In this lecture, I talked about the following things -
• Test circuit
• Component Selection
• PCB Design
• PCB Manufacturing
• Components Placement

I started with this DIY tutorial -

After a week of getting parts from Home Depot, e-bay and Amazon.com

I entered this state

urrg. maybe I will make a video and cry for help soon.

Lecture 1 – Electronic Components  [pdf]
Resistors– Ohm’s Law– Resistor in parallel / series– Voltage divider– Wheatstone bridge• Capacitors– Gauss’s Law– Capacitor in parallel / series
• Inductors
• Diodes– Zener diodes
• Transistors
• Op Amps– Ideal model– Comparator / Schmidt trigger– Voltage follower– Non-inverting   Amp / Inverting Amp– Summing / Differential Amplifier

Lecture 2 – Basic Filter Design  [pdf]
• Capacitor (Inductor)
-RC circuit
-Time constant
• Complex numbers -complex plane…
• Decibels (dB) -cut off frequency -half power point -F3dB
•  Filters- Low-pass, high-pass -MFB band-pass filter

Lecture 3 – Sensors and Sensor Design [pdf]
• What is a sensor
• How to read a datasheet
• Example signal conditioning
• Sensing on a surface – Pressure and Force
• Remote Sensing – Detecting “the Field”
• Multi-target or Multi-sensor?

Background

Before we start, a quick overview about what this is about- .NET Gadgeteer is a new open source platform based on the use of the .NET Micro Framework. What this really means for me is that I can write higher level code (C#) for a complex electronics project with the .NET framework which supports a real-time debugging environment. I build my own circuit board and chose my favorite microprocessors most of the time in order to adopt the circuit for specific applications. However, Gadgeteer comes with modular peripherals which allow you to plug in and not to worry about the physical connection, power, and modularity in the early stage of your development. It also comes with a powerful ARM processor (on EMX module which contains ARM Processor, Flash, RAM, Ethernet PHY…etc),   which reminds me of the Begalboard which is a hardware platform based on TI ARM-A8 processors.

.NET Gadgeteer provides a nice hardware interfacing platform for electronics hobbyist to build projects that requires more computing power with very little knowledge requirement on the hardware end. The development environment allows you to drag and drop components in a graphic user interface manner and automatically includes the libraries for you.

My step by step tutorial is for people who just received their starter kit and can not wait to plug everything in and make something blink. I found it hard to find a tutorial simply lists all the things one needs to know.

Now, I would like to talk about our experience in setting up a FEZ Spider Starter Kit. .

Setup – software
Things to install – You can find everything from this link – http://www.tinyclr.com/support

System preparation
1.  Microsoft Visual C# Express 2010
2.  Microsoft .NET Micro Framework 4.1 SDK
3.  GHI NETMF v4.1 and .NET Gadgeteer Package Feb. 24, 2012

This installs all the necessary SDKs and components.
First Project Settings    http://wiki.tinyclr.com/index.php?title=First_Project

Beginners Guide to C# and the.NET Micro Framework
http://www.ghielectronics.com/downloads/FEZ/Beginners%20guide%20to%20NETMF.pdf

Setup- Hardware

The mainboard (in our case, a FEZ spider 1.0 mainboard) comes with 14 sockets marked with letters.

The first application we tried to setup is as follows

1. A button that can trigger an event — input device
2. Being able to draw something on the touchscreen — output device
3. Reading signals from Pulse Oximeter and temperature/humidity sensors — events

Sockets mapping – First, what you need is the socket mapping diagram -

 The pulse oximeter transmits signals through UART (indicated by the “U” on the sensor board), the button and temperature/ humidity sensor use GPIO pins (indicated by X: 3 GPIO and Y: 5 GPIO) . The LCD is connected with “R”, “G”, “B” and “T” (touchscreen).

The wiring is as the following image.

You also need the power board which connects to “D” – USB device. It’s pretty straightforward once you figure out the letter matching scheme.

Before you continue, make sure when you plug in, you finished the “First Project Settings    http://wiki.tinyclr.com/index.php?title=First_Project “ and had successfully pinged the device and set up the project.

Now, we are ready for some action.

First, start visual C#,

File → New Project… select Gadgeteer and then select “.NET Gadgeteer  Application -> ok

Then you should first see the Program.gadgeteer page.

But I still cannot help to share the great discovery I made last week.
Before that, let’s cover the bases. There are color bands on a through hole resistor and the numbers are arranged in the same way as the color of the rainbows (sort of).

Black Brown Red Orange Yellow Green Blue Violet Grey White …

http://en.wikipedia.org/wiki/Electronic_color_code

I always thought those numbers were randomly assigned just because rainbows are pretty until last week.

Long story short, Nan and I blew up a light dimmer while trying to reverse engineer the circuit. After the magic smoke, we tried to figure out exactly which resistor was blown by reading the value of the apparently troubled resistor…

First, we measured it just for fun… and of course, “beeeeep”, said the multimeter (which means it’s a short circuit, zero ohm in multimeter language).

Then, naturally, I tried to read the value to show off the fact that I remember the color of the rainbows.

“Okay, it is black-black-black-black….”

“hmmmmm???”

“ohhhhhh….”