Arduino is not so much a specific product or technology, but an ecosystem of hardware, software, tools and human resources that have grown up around Atmel’s megaAVR family of 8-bit MCUs.
I/O expansion (shields)
Nearly all Arduino boards can be easily expanded using mezzanine-style add-on cards known as 'shields' that connect to the MCU’s bus and I/O signals using simple 0.10” pin headers. The shield’s stackable mix-and-match connection system makes it easy to add I/O or other expansion circuitry using commercial pre-assembled boards available from several manufacturers or one of the many pin-compatible expansion shield kits on the market.
The Arduino platform has caught the interest of both the hobbyist and commercial embedded communities, resulting in a large number of specialized shields including relay boards, high-resolution multi-channel D/A or A/D converters, AC or DC power controllers, and motor controllers. Connecting an Arduino board to a wired network is easy, thanks to several Ethernet shields that are commercially available.
The Arduino Ethernet Shield connects your Arduino to the internet in mere minutes. Just plug this module onto your Arduino board, connect it to your network with an RJ45 cable (not included) and follow a few simple instructions to start controlling your world through the internet. It is based on the Wiznet W5100 ethernet chip (datasheet). The Wiznet W5100 provides a network (IP) stack capable of both TCP and UDP. It supports up to four simultaneous socket connections. Use the Ethernet library to write sketches which connect to the internet using the shield. The ethernet shield connects to an Arduino board using long wire-wrap headers which extend through the shield. This keeps the pin layout intact and allows another shield to be stacked on top.
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| Official Arduino Ethernet Shield |
As always with Arduino, every element of the platform – hardware, software and documentation – is freely available and open-source. This means you can learn exactly how it's made and use its design as the starting point for your own circuits. Hundreds of thousands of Arduino boards are already fueling people’s creativity all over the world, everyday.
- Requires and Arduino board (not included)
- Operating voltage 5V (supplied from the Arduino Board)
- Ethernet Controller: W5100 with internal 16K buffer
- Connection speed: 10/100Mb
- Connection with Arduino on SPI port
- The current shield has a Power over Ethernet (PoE) module designed to extract power from a conventional twisted pair Category 5 Ethernet cable:
- IEEE802.3af compliant
- Low output ripple and noise (100mVpp)
- Input voltage range 36V to 57V
- Overload and short-circuit protection
- 9V Output
- High efficiency DC/DC converter: typ 75% @ 50% load
- 1500V isolation (input to output)
The Arduino Motor Shield is based on the L298, which is a dual full-bridge driver designed to drive inductive loads such as relays, solenoids, DC and stepping motors. It lets you drive two DC motors with your Arduino board, controlling the speed and direction of each one independently. You can also measure the current absorption of each motor, among other features. The shield is TinkerKit compatible, which means you can quickly create projects by plugging TinkerKit modules to the board.
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| Official Arduino Motor Shield |
Summary
- Operating Voltage: 5V to 12V
- Motor controller L298P, Drives 2 DC motors or 1 stepper motor
- Max current 2A per channel or 4A max (with external power supply)
- Current sensing: 1.65V/A
- Free running stop and brake function
Arduino-based motor control shield
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| Rated for operating voltages of up to 30 V and 2.8 A peak output, this commercially-available Arduino-based motor control shield can drive two DC motors for robotics or motion control applications. (Courtesy of RuggedCircuits) |
It is also easy to add wireless capability to your Arduino design. Shields that support ZigBee, Bluetooth and 801.11 wireless protocols are available. There are also several shields that contain a complete GSM-based cellular transceiver that supports GPRS services and run on Arduino Uno and Mega boards using the voltage provided by a computer’s USB port.
The Wireless SD shield allows an Arduino board to communicate wirelessly using a wireless module. It is based on the Xbee modules from Digi, but can use any module with the same footprint. The module can communicate up to 100 feet indoors or 300 feet outdoors (with line-of-sight). It can be used as a serial/usb replacement or you can put it into a command mode and configure it for a variety of broadcast and mesh networking options. The shields breaks out each of the Xbee's pins to a through-hole solder pad. Included on board is a SD card slot.
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| Official Arduino Wireless SD Shield |
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| Xbee shield allows an Arduino board to communicate wirelessly using Zigbee. It is based on the Xbee module from MaxStream |
The Arduino BT is a microcontroller board based on the ATmega168 and the Bluegiga WT11 bluetooth module. It supports wireless serial communication over bluetooth (but is not compatible with Bluetooth headsets or other audio devices). It has 14 digital input/output pins (of which 6 can be used as PWM outputs and one can be used to reset the WT11 module), 6 analog inputs, a 16 MHz crystal oscillator, screw terminals for power, an ICSP header, and a reset button. It contains everything needed to support the microcontroller and can be programmed wirelessly over the Bluetooth connection. Instructions are available for getting started with the Arduino BT.
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| The Arduino BT is a microcontroller board based on the ATmega168 and the Bluegiga WT11 bluetooth module. It supports wireless serial communication over bluetooth |
In much the same way Linux migrated from the open-source community to the commercial software market, Arduino’s low cost and versatility is beginning to build a loyal following among commercial hardware developers. While many initial applications have been developed by hobbyists and academics, it is expected that the Arduino technology used to create them will quickly find its way into commercial products.
