Arduino as a Microcontroller Reference Platform

The Arduino line of microcontrollers has, arguably, been the spark that brought programmable hardware to Makers worldwide. This article takes a look at how Arduino furthered the use of microcontrollers and how it is important defining standards today.

Arduino dates back to Hernando Barragán's design of the Wiring platform in 2004. In 2005, Massimo Banzi, with David Mellis forked the Wiring source code and started running it as a separate project. Arduino use grew through successive product releases including the Arduino Diecimila, Arduino Duemilanove, and the baseline Arduino Uno board series (in its third revision). The evolution set the Atmel ATmega328P microcontroller in the Uno to become the microcontroller standard of its time.

The Arduino Uno R3 (photo via Adafruit)

The ecosphere of Arduino, consisting of the circuit board and Arduino Integrated Development Environment (IDE) became very compelling for developers. Many software libraries were created to extend Arduino software capability and hardware connectivity. This growing capability launched the ATmega328 into many project designs. The success of the Uno board design led to other companies and makers to make Uno compatible boards based on the '328. The price of the Uno was set at the time at $35 and it did not go on sale often, requiring an investment on the purchase of each board.

In expanding the Arduino product line, the Arduino team introduced other boards based on newer microcontrollers. Some have been more widely adapted into maker designs than others. Many software libraries required changes to support different microcontroller architectures.

The development of the Atmel ATmega328P has evolved from the ATmega168 and smaller ATmega8, which all use the Atmel's AVR architecture. The '328 chip runs at a nominal 16 MHz (on the Uno) with 32 kilobytes of flash memory. This is modest by computer standards, but this chip equalled much of the industry when it was introduced.

The Arduino team, in looking for better designs, introduced the Arduino Leonardo. Leonardo was based on the Atmel ATmega32U4 microcontroller with the same 32kB of flash at 16 MHz. The chip was mostly compatible with the '328 but also had the feature of native USB controller onboard, eliminating the need for a separate USB chip on boards such as Uno. The Leonardo was less popular than the Uno but found some interesting uses due to features not found in other microcontroller boards. The native USB was very popular with other company/Maker board designers who, to this day, use the ATmega32U4 and the Leonardo software to make compelling microcontroller boards at a low cost.

Arduino Leonardo (photo via arduino.cc)

Sadly the Leonardo has been discontinued by the Arduino team but the use of the ATmega32U4 lives on in many new designs.

The Arduino Due was the Arduino team's first commercial step into the Atmel SAM architecture chips. SAM features an ARM processor, capable of speeds much higher than the Uno/Leonardo 16 MHz and also capable of more flash and other compelling features. The Due, being the first Arduino SAM board did (has) not find (found) a wide following in products or maker projects but it did (has) start software migration of the Arduino software base to use non-AVR chips. (Note: While announced as discontinued, they are still available via arduino.cc).

Note: Yes, I am skipping some Arduino releases here and there which are also AVR based designs.

The Arduino Zero, beta tested in 2014 with release in 2015, has become the new tier for microcontroller designers. Based on the newer Atmel/Microchip SAMD series, the board provides the SAM higher clock rates, ARM core, and a much smaller size.

Microchip recently bought Atmel, hence the processor provider name change.

The Zero has not supplanted the venerable Arduino Uno, yet, but the day draws closer where there are no arguments for selecting the more modern chip. Variants are smaller and much easier for manufacturers to incorporate. The Arduino Zero software is defining a new generation of compatible boards, especially from Adafruit.com which is revising a number of their microcontroller boards to use the SAMD chips. The third party boards are often less expensive than the Zero as the Zero design uses an additional debug hardware chip not used by most hobbyists.

It is conceivable that Microchip may look to discontinue AVR production through price hikes, leaving the SAMD and possibly their own PIC lines more widely available.

Arduino Zero (photo via Adafruit)

Where does the flood of Arduino compatibles leave the Arduino team?  Actually in a fairly good spot. The team are the Research and Development group foremost, providing both the low level chip firmware and the ever more powerful IDE to tap into new chips. The Arduino team continues to bring forward very compelling boards in different form factors: the Arduino Zero, MKR1000, and MKRZero boards have a great amount of capability at a cost lower than the Arduino Uno of old.

The Arduino team also has been collaborating on non-Microchip boards, including Arduino Yun, Arduino 101, and others. They also are important in expanding both the capabilities of the Arduino ecosphere and in partnering with companies other than Microchip to include Intel. The ability to easily use new, powerful microcontrollers and Linux based processors only benefits the ability of both companies and Makers to use the newer processors.

We all can look forward to the growth of the Arduino family tree, which has grown from a seedling over ten years ago. The innovation of the Arduino team has enabled people worldwide to harness some incredible hardware in making incredible products.

The Retired Arduinos

Arduino.cc has announced the retirement of some of their products.  This includes some mainstays as well as some specialty products.

Some of the retired Arduino products, more here.

Some of these are expected.  The Mega ADK was a specialty product.  The Arduino WiFi Shield was ill-placed - just over three years ago I called it out as way expensive at $85.  The Leonardo was always more of a concept for using the 32U4 chip.  The design sparked many successful clones but the board itself was not featured in many designs as I tried to find in October 2012.  The Arduino Robot was in a niche - it was a commercialization of support to a European robotics team.  It was very expensive and did not receive much focus from hobbyists.

One product closer to my work is the Arduino Esplora.  Many folks had praised the design, but not many projects came out.  I published some of the first projects including the work on pin outs and compatible displays.  Two things hampered the platform: the insistence of using the Tinkerkit inputs and outputs (which no one used in published projects), and the power requirement via a USB connection (when a battery power option would have been the way to go).  The Tinkerkit issue has also plagued other retired projects including the Robot and the USB Host Shield.

Lessons Learned

If you look at new Arduino.cc offerings, you can see the evolution of Arduino products.  New Arduinos consider LiPo battery use and using more affordable components like ESP8266 based wi-fi modules. Certainly the new MKR1000 board is a welcome addition.  We are in for exciting times ahead.  What are your thoughts?

Arduino Competition Causing Pricing Pressure

The assault by the microcontroller industry on the $30 Arduino Uno and its siblings is in full effect.

Once something becomes popular, people want them but prefer them cheaper, better, or faster.

The Arduino team has been working on this with mixed results.  The bigger and faster Due is still in a sort of beta with very poor software support compared to the mainstream Uno. The lack of add-on boards supporting the software and lower operating voltage has severely limited widespread adoption.  Better - in the form of Leonardo - has been very quiet except for the adoption of the chip and bootloader into many competing products (some rather good).  The Esplora is now carried in stores beyond the Radio Shack launch partner but the Esplora forum on the Arduino site is crickets, no activity.  All of this, with prices showing very little flexibility in the last year.  Those companies that priced the Uno at $35 have tended to lower the it to a fixed $29.95 price point.  Only Microcenter has shown flexibility, pricing the Uno down to $15 before relenting and having it bounce back to $25.  Finally Sainsmart has lowered their Arduino Mega R3 board down to $16.99.

Competition

1. Kickstarter - it seems everyone can and has come up with Arduino clones in every shape and size.  The trend though is than they are nearly always less expensive, the tiny ones very much so.  Keep an eye on the Spark Core that is red hot.

2. Clones using better chips - the Teensy and recently a line of Freescale processors have offered more capability at cheaper price points.

3. The big boys - yes the Raspberry Pi is not an Arduino competitor but adjunct, yes?  Yes and No.  Some of the Arduino's educational sales may be on hold while they learn about the Pi.  Boards like the Coocox Embedded Pi allow a Raspberry Pi to act as an arduino with shield support at an Uno price.  Finally the wildly popular UDOO combines Arduino Due and 4 times the Raspberry Pi power into one board.  The market also is receiving price pressure from Android and even small PC board makers with prices from $50 to $100.

Will innovation keep the official Arduino platform at current prices or will we see pressure to move manufacturing to Wales, UK (unlikely).

Excellent Arduino Pinout Diagrams

Several high quality color pinout diagrams have been posted to the Arduino forums.  These are very helpful for knowing the basic and advanced functions of Arduino boards.

The first to be posted was for the complex Arduino Due (above) by user Graynomad.  Then user Pighixxx used similar layout to do diagrams for the Uno, Mega, Esplora and more.

For readers, I link to the forum posts for various diagrams.  This allows you to get the latest version in case of revisions (the forum is keen on spotting any problems which keeps the quality of the diagrams very high).

• Arduino Uno with additional diagrams on the ATmega 328 and ATTiny chips
• Arduino Mega
• Arduino Leonardo with Mega 32U4 chip diagram
• Arduino Due
• Arduino Esplora
• Arduino Nano
• Arduino Mini

Also with the Uno, Pighixxx laminated a printout and mounted it on a plate and mounted a real Uno which makes a great prototyping plate (probably more detailed than a beginner might want, I would say a great target would be for technical or college level classes).

One doesn't need this level of detail for their first Arduino project but for midlevel to advanced work, these are wonderful and bring together information it could take hours to research.  Thus you have more time for actual experimenting (and debugging).

Arduino Micro and Other Tiny Boards

Arduino introduced their latest product today - the Arduino Micro comes with headers, operates at   5V and sports a 16 MHz ATmega32u4. The unit is basically a mini-size Arduino Leonardo as the unit can act as a USB host and it does not have an FTDI USB chip.  The unit has a USB micro socket.  The price is $24.95 US plus shipping.

I was reading the comments on Adafruit's post for the product and they appear somewhat mixed.  I would tend to expect this myself.  Why?

1. The Freetronics LeoStick came out many weeks ago and is priced at $28.50 shipped in the US from reseller EpicTinker or direct from their Australia based operation.  The product plugs directly into a full-size USB port so no cable is needed for programming or interfacing as a USB host.  It also has headers (not standard shield compatible but you could make your own).
2. The large number of small form-factor Arduino-compatibles.  Very successful Kickstarter projects like Digispark and TinyDuino bring compatible devices at around the $22 mark (about the same price as a full Arduino Leonardo.
3. The new 32-bit tiny powerhouses led by the Teensy 3.0 at $27.95 US have much of the power of the Arduino Due in the small form factor.

All this would probably not be possible without leveraging the existing Arduino integrated development environment (IDE).  But is loyalty to the brand enough to guarantee volume sales? 

The Prius was the first mass produced hybrid and has a strong following.  But there are many electric or hybrid cars now, some rather reasonable.  Does one stick with the market leader or consider something like the new Tesla Model S?  The choice is yours - viva la choice.

I found some Leonardo projects - and they're cool!

I have previously bemoaned that I had not seen many (ok, any) Arduino Leonardo projects.  I have a saying that if you see something once it is cool, if you see it twice, it's a trend.  Via my post on the Raspberry Pi AlaMode board, I saw a post from those folks on an FM radio interfaced with Arduino.  Well tonight I browsed Club Jameco (sad but true) and saw an idea for a sound localization board for Arduino (cool!) and the author is the same as the FM radio author.

Magiciant writes the coolarduino blog.  He's doing some signal processing on Arduinos that is very interesting.  My favorite is a sound localization add-on (above) using 4 electret microphones for x and y axis tracking.  Another is a speech recognition project.  These are things I was investigating with the Raspberry Pi.  Just coincidentally, Adafruit has come out with both a very good electret mic and a mic+amplifier.

Finally, to get better capability, magiciant has migrated his initial designs to the Leonardo, apparently due to input sensitivity and a couple other factors.

This may move my robotic head project forward - I have the head and servos, now to have them do interesting things.