Connecting multiple boards together with ChainDuino

After a highly successful Kickstarter campaign, the ChainDuino project has entered its final stretch of crowdfunding.

Michael Tedeschi originally created the ChainDuino after realizing that he wished it were simpler to connect multiple Arduino Uno (ATmega328p) boards with readily available Cat5 cable. To get the ChainDuino idea off the ground, he set a crowdfunding goal of $2,500, which has well exceeded by raising over $8,800 to date.

According to its site, the ChainDuino is a daisy-chainable, Arduino-compatible development board that enables Makers to easily connect multiple boards together with standard Cat5 cable. The boards communicate using built-in RS-485 circuitry, and share power using passive PoE+ over the same Cat5 cable. Tedeschi’s design operates on an open source platform and allow news boards to be added to the chain simply by programming them with the Arduino IDE and plugging them in.

Tedeschi was fascinated with the idea of using an Atmel-based Arduino to monitor data from multiple locations simultaneously. “I needed a simple way to connect microcontrollers together to focus on the functions of each node, instead of wasting time solving how to connect the nodes to each other.”

Some have questioned why Tedeschi did not adopt wireless technology for the ChainDuino project, but he explains, “While I do find wireless gadgets fascinating, I have always been more of a hardwired fan when it comes to permanent installations.” He reveals he is also a proponent of powering remote devices over Cat5, also known as Power over Ethernet, or PoE.

Tedeschi has found that up to 25 boards can be linked using his system and has successfully tested the unit at a mammoth length of over 1,600 feet!

Upon reaching his funding goal, the Maker will first and foremost be using the money to fill Kickstarter backer’s orders of the ChainDuino. He will then look to begin developing an enclosure and further prototypes. He also has thoughts of adapting his design to work with either an Arduino Mega (ATmega1280) or an Arduino Pro Mini (ATmega168).

The board layout is loosely based on the Arduino Uno (without the USB):

• Microcontroller: ATmega328P
• Operating voltage: 5v
• Input voltage: 7-28v DC
• Digital I/O:14 pins (6 pwm)
• Analog Inputs: 6
• DC each I/O: 40ma
• DC for 3.3v: 150ma
• DC 5v onboard: 500ma
• Clock speed: 16 MHz

Additional features include:

• RS-485 half-duplex MAX485 chip onboard (pins 0,1,2)
• RS-485 terminating & bias resistors selectable with dip switches
• 28v DC switching regulator supplies 5V up to 500ma
• VIN pin on Arduino header disconnected by default to protect some shields from > 12v (enable with simple solder joint)
• PoE+ support for 24v DC power over Cat5
  passive PoE pins (+) 4,5 and (-) 7,8
• I2C pullups onboard, disabled by default (enable with solder joints)
• FTDI headers onboard
• ICSP header onboard
• Daisy-chainable via RJ45 ports or IDC connectors
  (insulation displacement of 24-26 awg wire)
• WS2812b RGB LED onboard (pin 13)

For more information about the ChainDuino, you can head to the project’s Kickstarter page.