Arduino Shield Compatibility Documentation

There does not appear to be any site that attempts to cross-reference Arduino shields and compatibility between Arduino processor versions (Uno, Mega, Due, Leonardo, Micro, Nano, etc.).

I asked Adafruit during their Saturday Ask an Engineer chat if they have plans to do this (at least for their own products) and they indicated they would like to but it's not high on their list (understandable as they are working on new products and learning tools.

Perhaps some industrious soul(s) would set up a website/wiki to document shield compatibility?

Raspberry Pi in Stock at Newark

Newark has the Raspberry Pi in stock at the standard $35 price point, no limit.  They state they have twenty but that does not decrement.  The link is http://www.newark.com/raspberry-pi/raspbrry-modb-512m/raspberry-pi-model-b-board-only/dp/43W5302

Try code MONDAY75 to get free shipping on $75 and up orders.

Lots of Sales, Items Running Out

I like to shop the early sales but I have found that certain items I want to buy, especially at Maker stores, are out of stock.  Hard to see a sale but no stock.  I jumped when Adafruit got RFID boards back in but there are still many things they carry that are out of stock (but understandable given Sandy).  The Arduino Due seems very elusive (but I have one in route from Maker Shed from a week ago).  Maker Shed briefly stated they had more stock but it was a stock error.

I may be looking for a new laptop - the Dell XPS I wrote of earlier is having issues again (not too unexpected) - it will keep running if left on but that isn't very reliable.

I have been organizing the shop a bit more so it should be easier to work.  I got some vintage parts drawers off eBay to match my vintage drawers I got back in the 70's/80s (plastic drawers really have not come down in price).

I've ordered some cool parts so I should be able make some great things.

Wiring up Bob the Robotic Head #hackfriday

No, I did not forgo Black Friday shopping altogether for Hack Friday (the new day which one spends hacking things together).  Shopping started at 7:30 Thanksgiving with a trip to Walmart and also some online shopping.

Hack Friday started a couple months ago buying a robotic head.  It comes with two servo motors and two electric motors.  About the same time I bought an Adafruit motor shield to control the head via an Arduino.  I have not had time to wire it up with other projects like the Cylon Pumpkin.  With Halloween over, I wanted to focus on the robot. Helping was receipt today of another Adafruit order from this past Sunday when they had a 10% off sale for Hack Friday.  Just in time!

The head is driven with the motor shield's two servo outputs and two of the four motor controllers.  For now, a potentiometer is read to control the motor and a rotary encoder, interrupt driven, selects which motor to control (could be done with 4 potentiometers possibly better).  The motor shield leaves enough Arduino pins free (all analog pins and digital pin 2 which is interrupt controllable).  Eventually the head will respond to sensors and possibly talk via an Emic speech board coming from a sale at Make.

Making the hookup much more enjoyable is my new Hakko soldering iron - near instant controlled heat, making the old Radio Shack model seem so 1976.

Happy Hack Friday!

Cylon Pumpkin Build Details

By request, I am posting details on my Cylon Pumpkin build from two weeks ago.

Inside the parts look like this

The Larson Scanner (moving LED array) with its AA battery pack is at top.  It is a kit from Evil Mad Scientist.  The board in the center, (underneath) is an Arduino Uno.  On top of that is an Adafruit Wave Shield.  It's a kit and yes I didn't get it right when complete, I had a cold solder pad on the SD card interface.  This plays the cylon sounds - this consists of the moving eye sound and then 6 phrases that can be triggered from an IR remote (not shown, any remote will do, more below).  The IR signals are captured by a Radio Shack IR receiver (black, between the two blue boards).

The unit is powered from a 9 volt battery connected to the Uno.  The audio out on the Wave Shield was amplified as the volume produced by the shield was not very loud.  I happened to have a vintage Radio Shack mono amplifier.  The Uno+Shield+Battery were housed inside the pumpkin in the plastic case at left (from Michaels, use your 40% off coupon).

Wiring: The Wave Shield connections are as recommended by Adafruit (using Digital pins 2, 3, 4, 5, and 10).  The IR sensor was coded to use Digital Pin 9 (along with +5 volts and ground).  The astute will notive I did not take the ausio from the 1/4" jack (not enough room in the plastic box) - I soldered two 90 degree header pins on the board's audio out and connected the yellow and orange cable to a 1/4" plug.

Code: The code is at https://github.com/TheKitty/CylonPumpkin. You should get the WaveHC and WaveUtil libraries from adafruit.com. IRremote library by Ken Shirriff at http://arcfn.com. You should use one of the IRtest programs with Ken's library to discover the codes for whatever remote you chose. I used an old Creative RM-1500 remote but you can use any remote and map the codes you discover to the keys you push. This project used number keys 1 to 6 for effects, mute to turn off sound, Volume + to turn it on. The code is not overly clean as there was a bug with the mute button so I ignored presses that turned out to be just over 1.5 seconds. It was frustrating - you'll probably have better luck. The sounds can be found via Google "Cylon WAV". I cannot post the sounds as they may be copyrighted.

Other than the mute issue, it was a straightforward and fun build.  I'll look to reuse the Uno and Wave Shield to try out the Adafruit Voice Changer.

Online Courses - Refined and Redefined Learning

Online learning is finally coming into the promises made in the early Internet.  From MIT CourseWare to Khan Academy to today's offerings, it's all getting better.

If you haven't heard of Caltech's "Learning from Data: Introductory Machine Learning Course", it's well worth a look.  Dr. Yaser Abu-Mostafa is one of my favorite professors and I learned a great deal in his courses.  He's redefined excellence in online learning with his course.

This quarter's issue of ENGenious (the magazine of the Division of Engineering and Applied Science at Caltech) has a great interview article about the course, the professor, and the process.  If you've thought about jumping into university level courses from a top (well, #1) rated institution, I seriously recommend checking out the course offering.  And the price is right.

Deals at MicroCenter

Last month, I blogged that MicroCenter had been touting their "Arduino" (which turned out to be a Ghio clone) for $19.99.  Today's ad is out and the new and improved prices are out.  They state they have the Arduino Uno Rev 3 for $17.99 (item # 869016) and the Mega 2460 Rev 3 for $34.99 (item # 864504).  No sign they are the clone models in their ad.  If that is the case, their Mega costs what Radio Shack charges for the Uno, the prices approaching half what the maker shops charge.
Such pricing could threaten Radio Shack's foray into the Maker market.  I hope not, I have encouraged them to get back to their golden days of electronics.  I spent much of my teen years pocket change buying Radio Shack parts and books.

If you'd like a Maker's kit, MicroCenter has the Sparkfun Inventor's Kit at $69.99 (item # 434324).  It was selling at $99.99 but Sparkfun recently redesigned the box so this is last year's box (link to current model) but it is still cool and $30 off.

If you like PC's, it's hard to beat some of MicroCenter's prices.  They have several stores around the US (yes, there is one nearby here) but you can get most of the same prices online (except processors which are only discounted in-store).