Mixing and Amplifiying Your Audio Sources

As I build more complicated Arduino projects, I'm finding I have several audio outputs in one project. Instead of offering a amplifier and speaker for each source in the same project, I decided a needed a mixer, with one amplifier and speaker. The following talks about the various types of mixers (passive and active), the pro's and con's of each, and how to work through things like impedance matching, distortion and clipping.

http://www.all-electric.com/schematic/simp_mix.htm

For an amplifier, it's hard to beat a good set of amplified computer speakers for this application. The Logitech S120 2.0 Multimedia Speakers are very inexpensive (<$11), and give great quality sound.

BTW, today is my birthday, so please check out my Arduino Store, and you can celebrate with me!

The Most Important Arduino Book?

There are a lot of good Arduino books out there. Most teach you how to install the editing environment, how to code, and neat projects like blinking a LED, reading a light sensor, or controlling a motor.

Only one teaches you about motion, the science behind it, and how to make your Arduino interact with the real world through electro-mechanical, pneumatic, and hydraulic ways. Learn how to size motors for a particular task, how to determine rpm and torque requirements, and much more.

I believe this is the most important Arduino book available, and it has a prized position at my work bench. I recommend it highly!

Making Things Move DIY Mechanisms for Inventors, Hobbyists, and Artists

Using Mosfets

I'm working on a LED lighting project. The LED's consume more power than a Arduino can handle, so I'm using a IRL520 MOSFET to control the lights.

The first phase of the project is simple on and off, the second phase will PWM the MOSFET for brightness of the LED's. Third phase is 3 MOSFETS each controlling a different color bank of LED's for tonal control.

What we have working in phase 1:

+12vdc to 3 white LED's in series with a 120 ohm resistor

This configuration was determined using the LED Wizard at http://led.linear1.org/led.wiz

The next step was to insert a IRL520 MOSFET is series with the LED's, between the resistor and ground. The Drain (pin2) connects to the resistor, the Source (pin3) connects to Ground. The Gate (pin1) can be tested by connecting to +12v (momentarily, not good to exceed 10v) and Ground, alternately.

WAIT!

What have we discovered? The output (LED output) toggles with the gate connection. When we touch +12 momentarily, the LED's light up, and stay lit even after the Gate is no longer touching +12v. When the Gate is grounded, the LED's go out, and stay out, until Gate touches +12v again. We need to connect a 10k ohm resistor between Gate and Ground, so that the LED's are off unless power is applied to the gate, which will be +5v from Arduino pin 13 in the next example.

Schematic generated in SchemeIt, a free online schematic tool.

A platform for microcontrolled electro-mechanical, hydraulics, and pneumatics

We've talked about Grid Beam as a inventors and experimenters dream before, but the more we dig into it, the more we get excited about it. If you missed our last article on the subject, Grid Beam is a system of easy to bolt together modular components made of metal, wood, or plastic. This system has been developed over the past 60+ years, starting with the original inventor, Ken Isaacs. He called the system "Living Structures".

Ideal for rapid prototyping, ease of disassembly, moving and reassembly. Fun for kids and adults. Solar mounts, wind turbines, hydroelectric, electric vehicles (cars, trains, submarines and more) are just some of the ways to use this system. We develop solutions using microcontrollers in a variety of electro-mechanical, hydraulic, and pneumatic applications and have many uses for grid beam as a platform for these solutions. Check it out!

How to build with Grid Beam

Isaacs, Ken - How To Build Your Own Living Structures (Free Download)

Open publication - Free publishing - More architecture

Arduino Robotics

This book by John - David Warren and friends is one of my favorites. A good beginning in electronics and Arduino basics (easily ignored if you are experienced, but I suggest a overview anyway), then jumps into well documented meat and potatoes robotics, including wireless control, motor control, and sensors such as ultrasonic, IR, and tactile. Arduino Robotics by John-David Warren (Author), Josh Adams (Author), Harald Molle (Author)

New Arduino IDE 1.0

A new programming interface, with some pretty major changes to available
routines, functions, and behavior in old functions. This one is important, check
it out at
http://tronixstuff.wordpress.com/2011/12/10/initial-review-arduino-v1-0-ide/

Join the Arduino discussions at http://tech.groups.yahoo.com/group/arduinohome/ .

Build your own Proto Shield for the Arduino

The biggest issue with protoshields, is the Arduino funky pin spacing. Mike Cook has a way to make larger protoshields with plenty of prototyping space. Handier than breadboards, as the project is more "permanent". Mike has been helping us with our Arduino / Mitutoyo Micrometer project, and has a bunch of great Arduino tutorials on his website. Check them out, though you will need to do a bit of digging, as he has all kinds of fascinating stuff posted.

http://www.thebox.myzen.co.uk/Hardware/Arduino_Shield.html

http://www.thebox.myzen.co.uk/Tutorial/Introduction.html

http://www.thebox.myzen.co.uk/Workshop/Introduction.html