Arduino

Great success at the Arduino 201 - Get Motorin' meetup.  Yes, those are groceries in the background.  All in, we had 11 people come out.  Special thanks to Solarbotics for L298 Compact Motor Driver kits, Adafruit Industries for a Motor Shield, Sobey's for the free room, and Cedric and Steph for the presentation monitor, photography (not these pics here, much better ones to come), and the infrastructure support.  Read on for details...

Tonight's fun centred on building the motor driver shield that Limor from Adafruit Industries kindly donated to support our Arduino 201 - Get Motorin' meetup this Saturday.

Read on for details...

Motor drivers have arrived from Solarbotics and Adafruit Industries.  Rejoice!  Just in time for some midnight soldering (had an "oh-yeah..." moment when I remembered these are kits of the all-assembly-required type) before our Arduino 201 - Get Motorin' meetup on Saturday.  That's the L298 Compact Motor Driver (CMD) shown above, generously donated to support our meetup by the good folks at Solarbotics (and there's another waiting on the bench to be assembled).

Read on for deets...

Gus was asking about limit switches today.  We were talking about driving motors and the upcoming Arduino 201 - Get Motorin' (May 23) meetup and he mentioned one of his applications required limit switches that signal a motor to stop running when something hits a certain limit of travel. 

Read on for details...

Aaahhh, toys.  Few things are sweeter to hack.  I started at age 4 by smashing all my squirt guns open to get the pumps and hoses inside.  Toys are great hacking fodder because:

• they're cheap to obtain: trash, dollar store, Winners, garage sales, etc
• you can learn a ton from observing optimizations in their construction, which are usually due to cost sensitivity, but sometimes due to ease of assembly
• they often offer complex functionality (that would otherwise cost you an arm and a leg) that can be easily repurposed such as speech modules, gear motors, etc

The point of this post is to illustrate how to programmatically "push buttons"  on a device using the Arduino.  Read on for details...

Another bit of scavenged gear to serve as an Arduino output device.  Somebody please chime in here to tell me the official name for these type of gauges.  This could be an interesting device to give an amusing analog measurement for something like your bug count, web server hit rate, outdoor temperature, number of unread xkcd entries, etc.

Read on for details...

Hot on the heels of last night's great success with Arduino 101, DW and Natalie have organized "Arduino 201 Meetup - Get Motorin'"

• What: now that you've figured out how to blink an LED with your Arduino, let's talk about driving motors!  Good for moving your robot, opening your drapes, rotating your telescope and a whole lot more.  We'll talk about the basic theory of h-bridges (a really useful configuration of transistors), build-vs-buy, speed control, driving different types of motors (brushed, stepper, servo, etc), and, of course, how this all hooks up to the Arduino.
• When: Saturday, May 23, 2009, 7pm to 10pm
• Where: Columbia Sobeys, 450 Columbia St. W, Waterloo, ON (corner of Columbia Street & Fischer-Hallman Road) upstairs in the community room
• How Much: Free no-pay
• Bring: all that's required is curiosity, but if you have 'em, bring your Arduino, laptop with Arduino software installed, and whatever motor you think you'd like to drive
• RSVP: required, email darin.white@rogers.com, 20 seats available
• Where to buy:
  • Adafruit Industries - ladyada kindly donated an additional motor shield on my order today.  She also has Duemilanove Arduinos for sale.  When ordering, opt for USPS instead of UPS who kills you with brokerage charges at the border.  And order soon for USPS if you hope to have your gear before the event.  Thanks Adafruit!
  • Solarbotics - the great folks at Solarbotics have donated 2 of their L298 Compact Motor Driver Kits for our event.  Rebecca also told me that starting this week their sister-company HVW Technologies is now distributing Duemilanove Arduinos.  Both Canadian companies offer reasonable shipping.  I've happily shopped Solarbotics for geared motors (awesome prices) and accessories.  Thanks Solarbotics!

Here's a reflective infrared light sensor I salvaged from a printer.  In that application they are typically used to detect the presence of paper, which is way more reflective than the dark plastic insides of the printer.  These can useful for detecting light and dark surface transitions in projects like line-following-robots.  Only 2 resistors are required to hook this up to the Arduino...

By request: hooking up a piezo buzzer to the Duemilanove to make sound. 

A piezo element is just a bimetallic sandwich, usually circular and stuffed in a small case, that bends when you put a voltage across it.  If you alternate between, say, 5 volts and ground across the piezo, then the ensuing bending creates waves in air which we call sound.  Some piezo units come with built-in drive circuitry that will create that alternating voltage for you: just hook up power and ground.  Most that I salvage are just the piezo element, so I need to provide my own wave.

This salvaged bit with 5 pots was from a Sony monitor I believe.

Thought I should figure out a few things about this Duemilanove board before the Friday meetup.  To that end I rummaged through my lab to collect a bucket of parts that might illustrate some fundamental "peripherals" people might like to see connected to an Arduino.  Collected LEDs, switches, pots, an LDR, a VU gauge, a hall sensor, a servo, an L293 h-bridge, and an LCD from an old printer console, shown here: