What is "Minimalduino"?

I started working on the "minimalduino" design as...

1. a minimal hardware design for an Arduino-compatible board. At heart, it is very similar to the Dorkboard, but
2. designed to match the form factor of the "official" Arduino boards so users can benefit from the many, many shield boards designed to fit on top. While (awesome) boards like EMSL's Diavolino are also low-cost and shield-friendly, I wanted to explore
3. optional hardware configurations, with different power connector options (pin headers, JST connector, barrel jack, screw terminals, or mini USB jack), 5V and 3.3V power regulation and optional voltage switching and regulator bypassing, and options for crystal and caps or a resonator. I also wanted to have
4. better shield-friendliness by placing LEDs (power and D13) and the reset switch (side switch or top switch) at the edges of the board, and lastly, I wanted the board to be
5. single-sided, home-etchable with wide traces and minimal jumper wires. There is still work to be done to reduce jumpers, but it improves on the the S3V3 "Severino" board which doesn't match up size-wise (it's bigger), the standoff mounts don't match, and it uses a DB9 serial connector instead of the now widespread FTDI USB-serial breakout cable.

Arduino: What Direction?

In spite of the year-end hype surrounding the Arduino Uno, and while I like seeing Arduino hit its 1.0 release, other Arduino-compatible boards get me more excited. If Arduino is a low hurdle access architecture for the ATmega**8 line of microcontrollers, I'd prefer the extra circuitry to be optional:

• Power regulation: why embed regulation in each board when it's not always needed? And what about regulation or step-up converters for battery-powered projects?
• Board voltage: There are good reasons to use 3.3V or 5V depending on applications, why are so few boards switchable?
• Programming interface: While USB (and its decoder chips) is ubiquitous, so (still) are serial and ethernet, and (increasingly) XBee. Why not make the programming/serial interface optional or external?
• Real estate: There is only so much room in the standard Arduino form factor. Why not use that space for useful circuitry that would be tricky to locate externally?

$30 is a fair price for a board with USB, power regulation, and automatic power switching, but half of that cost is not for the Arduino-capability! This is neatly demonstrated by the $13 Diavolino by Evil Mad Scientist Labs, which has no power regulation (but pads if you want to install it) and a header for the now standard 6-pin FTDI USB-serial breakout interface. Arduino-compatible boards' regulation, voltage, programming interfaces, and extra features are listed on my comprehensive spreadsheet.

Here are a few boards comparably-priced to the Uno that may be more useful for real applications since they have the Arduino core but different circuits for power, communication, or extra capabilities:

• Wiseduino ($34 kit) has a DS1307 real time clock with backup battery, a 256Kbit EEPROM chip, header pins for the Adafruit XBee adapter, and 6-pin FTDI cable interface.
• Freakduino Chibi ($33 kit) has built-in 802.15.4 (XBee) radio and optional ($3!) battery voltage regulation so you can input from .7V to 6V.
• Arduino FIO ($25) has a MAX1555 LiPo charger, power regulation, and an XBee socket.

What do you want in an Arduino-compatible board? Please leave a comment!

EMSL "Diavolino"!

Windell from Evil Mad Scientist Laboratories ("EMSL") announced a new Arduino-compatible board today: Diavolino!

Designed to be programmed with an FTDI USB cable (6-pin), the awesome-looking $13 kit comes with just enough to get started, including an ATmega328 pre-loaded with the Arduino bootloader. Pin headers cost an extra $1.50, and you can power it with an optional $1 3xAA battery box with switch, which should supply 4.5V (using alkalines).

Very cool kit from some very cool people, and (according to my Arduino-compatible board spreadsheet,) currently the lowest-priced way to get access to the big wide world of Arduino shields.

Update 6/24: Added the EMSL Peggy 2LE and Bulbdial Clock to the spreadsheet, though they're "maybe not" really Arduino-compatible :)