BUSNET :: Arduino Dongle
The first BUSnet hardware to be built is an Arduino dongle. This is designed to plug into an Arduino and provide a reliable RS-485 network interface to as many as 254 other Arduinos.
The BUSnet Arduino dongle serves two purposes, it is a proof of concept for the BUSnet protocol, and it is designed to be a marketable product as well.
The dongle plugs into the Power and Analogue headers on the Arduino, it is thin enough to be placed between the Arduino and a shield and does not disrupt any of the signals except A4 and A5 which are the I2C signals and therefore required to communicate with the Arduino.
The dongle can co-exist with other I2C devices that are being used by the Arduino.
What does it do?
The Arduino dongle is designed to make the reliable networking of Arduinos easy, just plug 2 or more (255 max) Arduinos in, invoke the auto-addressing feature on each device, then start publishing data using an I2C connection to the dongle.
There is no network programming required, the dongle's on-board microprocessor handles the entire network protocol so there are no libraries to include, "network stacks" to implement, or complicated timing to handle. Just treat the dongle as an I2C peripheral chip much like any other, the difference being that data published can be reliably subscribed to by other Arduinos in the next room or even several kilometres away.
What does it include?
The dongle has everything needed to daisy-chain Arduinos in an RS-485 network, including
How does it attach?
The dongle can be loaded with standard headers and plugged into the Arduino Power and Analogue sockets. If a shield is being use it can plug into the shield's sockets.
It can also be loaded with "pass through" sockets, these allow the dongle to be placed between an Arduino and a shield. This means that the dongle can still be used with shields that don't have stackable headers, such as most display and human interface shields (subject to the pin lenght of the shield headers).
About half of the dongle PCB protrudes inside the Arduino headers and the other half outside.
If standard headers are loaded the dongle can also be used on a bread board or other prototyping boards.
All electronics information and designs on this site is released
under the Creative Commons CC BY-SA and/or Open Hardware licences.
Copyright © 1973-2013 Rob Gray, All rights reserved.