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Arduino Inventor’s Guide CIRC-07 (Push Buttons)

This circuit makes use of push buttons to turn on and off a red LED light.

Arduino CIRC-07

Arduino CIRC-07


  • 1 x Arduino Duemilanove
  • 1 x Breadboard
  • 2 x Pushbutton
  • 2 x 10k Ohm Resistor (Brown-Black-Orange)
  • 1 x 330 Ohm Resistor (Orange-Orange-Brown)
  • 1 x Red LED
  • 7 x Wire

Additional Resources:


This one went pretty well with only one minor snag. The second button wasn’t correctly turning off the LED. I discovered that I’d bent back one of the pins underneath the button when installing it and it wasn’t correctly connecting to the circuit. Everything worked nicely once I properly reattached the button.  I also noticed that pressing the buttons quickly tended to cause the press not to register.  Something to keep an eye out for in the future.


Arduino Inventor’s Guide CIRC-06 (Piezo Element)

A piezo element clicks every time it is pulsed with current. This 6th circuit is designed to pulse a piezo at the right frequency to make the Arduino play to the tune of “Twinkle Twinkle Little Star”.


Arduino CIRC-06


  • 1 x Arduino Duemilanove
  • 1 x Breadboard
  • 1 x Piezo Element
  • 4 x Wire

Additional Resources:

This was extremely easy to put together.  I was surprised with how accurate the song sounded when the program ran.  Writing music for the piezo is not as easy as constructing this circuit, however.  I gave up after about an hour of attempting to rewrite the program to play another song.


Arduino Inventor’s Guide CIRC-05 (Shift Register)

CIRC-05 uses a 74HC595 shift register to control 8 additional outputs using only three pins on the Arduino.  These integrated circuits can also be linked together, resulting in a virtually unlimited number of outputs.

Arduino CIRC-05

Arduino CIRC-05


  • 1 x Arduino Duemilanove
  • 1 x Breadboard
  • 1 x 74HC595 Shift Register
  • 8 x Red LED
  • 8 x 330 Ohm Resistor (Orange-Orange-Brown)
  • 19 x Wire

Additional Resources:


This circuit takes awhile to correctly assemble, due to the amount of wires and resistors to hook up.  It’s pretty cool to see in action once it is working.  The Red LEDs each light up as the program loops through them – counting from 0 to 16 in binary.


Arduino Inventor’s Guide CIRC-04 (Servo)

The fourth circuit from the Arduino Inventor’s Guide controls a servo. Servos can be positioned from 0 to 180 degrees, and this positioning is controlled through a timed pulse.


Arduino CIRC-04


  • 1 x Arduino Duemilanove
  • 1 x Breadboard
  • 1 x Mini Servo
  • 5 x Wire

Additional Resources:

This circuit was really easy to wire up correctly and was also a lot of fun to see in action. I recommend playing around a bit with the code, changing delay and position values to see what effect it has on the servo. I think this will end up being a very useful component in future projects.


Arduino Inventor’s Guide CIRC-03 (Transistor and Motor)

The third circuit in the Arduino Inventor’s Guide uses current flowing through a P2N222AG transistor to spin a motor.

Arduino CIRC-03

Arduino CIRC-03


  • 1 x Arduino Duemilanove
  • 1 x Breadboard
  • 1 x P2N2222AG transistor
  • 1 x Toy Motor
  • 1 x 1N4001 Diode
  • 1 x 10k Ohm Resistor (Brown-Black-Orange)
  • 6 x wire

Additional Resources:


Despite the fact that this is a simple circuit to build, I just haven’t been able to get it to work. It has been rebuilt several times, using different wires, 10k Ohm resistor and a different P2N222AG transistor. I suspect I might have a defective diode or faulty wiring for the motor. I am unable to verify this as I only have one of each. Hopefully others are able to have more success with this circuit than I did. I will update this post if I finally get it working.


How to Add a Standard User to the /etc/sudoers File in Mac OS X

In order to use the sudo command with a standard account, it needs to be added to the sudoers file.  Perform the following steps as an administrator.

1.) Open sudoers file using visudo command.

2.) You will see the following block in the file

# User privilege specification
root ALL=(ALL) ALL
%admin ALL=(ALL) ALL

Copy and paste the line for the root account below the %admin line and rename it to the account you want to have sudo privileges.

3.) Save the file and exit (if in vi, :wq does this). You should now be able to sudo from your user account.

Arduino Inventor’s Guide CIRC-02 (Multiple LEDs)

The second circuit in the Arduino Inventor’s Guide is a little more complicated than the first one. This time there are 8 LEDs connected to the board, but the LED animation is still fairly simple. It iterates over each LED and turns each one on. Once they are all on, it then loops backward turning each one off. It uses:

Arduino CIRC-02Arduino CIRC-02
  • 1 x Arduino Duemilanove
  • 1 x breadboard
  • 8 x Yellow LED
  • 8 x 330 Ohm resistor (Orange-Orange-Brown)
  • 10 x wire (8 for pins to LEDs, 1 each for gnd and 5v)

This one I was expecting to run into difficulty with but after connecting everything it worked on the first try!

You can get a copy of the breadboard layout sheet here, download the code for the sketch from here, or watch an assembly video here.


Arduino Inventor’s Guide CIRC-01 (Blinking LED)

The first circuit in the Inventor’s Guide is a simple one that turns on and off a single LED repeatedly. I used:

  • 1 x Arduino Duemilanove
  • 1 x breadboard
  • 1 x 5mm Yellow LED
  • 1 x 330 ohm resistor
  • 3 x wires (1 each for gnd, 5v and pin 13)

You can download a copy of the breadboard layout sheet here, or watch an assembly video here.

This was a good introductory circuit to cut my teeth with correctly wiring the parts together, as well as uploading the C program to the Arduino from the IDE.


Arduino CIRC-01


Arduino Duemilanove Inventor’s Kit

I recently discovered the open-source electronics prototyping platform called Arduino.  I ordered the Arduino Professional Kit from and have been playing with it ever since.  It is a fun way to waste a couple of hours at night after work.  The device runs on C applications that you write for it using the Arduino IDE.  The kit came with:

Arduino Duemilanove USB
Printed 36-page manual
12 color circuit overlays
Clear Bread Board
74HC595 Shift Register
2N2222 Transistors
1N4001 Diodes
DC Motor with wires
Small Servo
5V Relay
LM335A Temp Sensor
6′ USB Cable
Jumper Wires
Tri-color LED
Red and Green LEDs
10K Trimpot
Piezo Buzzer
Big 12mm Buttons
330 and 10K Resistors
Male Headers

and doesn’t require any soldering skills to use, which is great if you’ve never soldered anything before like me.  For around $100 CDN including shipping, I highly recommend this kit to anyone that’s considered playing with hardware at all before.


How to Install the Eclipse Groovy Plugin

These instructions are from the official Groovy website.

Before you begin the installation, first make sure to a recent version of Eclipse.  I am using Eclipse 3.4.1 for my installation.

Installing the plugin from within Eclipse:

  1. Go to Help -> Software Updates
  2. Switch to the Available Software tab
  3. Click on Add Site
  4. In the Location text box paste this url: and press OK
  5. Click the boxes next to the groovy features you would like installed and then click on the Install button
  6. Click Finish to go ahead with the install.

If you have any problems or encounter errors during the install, have no fear!  There is another way:

  1. Download the .zip from
  2. Extract the content of the .zip into the Eclipse \plugins and \features directories.

The next time you restart Eclipse, you should have a working Groovy plugin.

Note: I have installed this plugin on multiple versions of Eclipse and have always had to use this second option.  The Groovy plugin has many dependencies within Eclipse that I can’t be bothered to track down and fix.  In the end, the .zip method still manages to get the Groovy plugin installed correctly.