Jetpack Cognition Lab's RS485 Shield Offers Safe Connectivity for Arduino Nano Boards
Available as a kit or fully assembled, the protected board allows up to 256 Arduino Nanos to communicate on an RS485 bus.
Robotics startup Jetpack Cognition Laboratory has released an RS485 shield add-on designed to bring the popular bus to the compact Arduino Nano board, offering support for up to 256 microcontrollers on a single bus.
Standardized in 1998, the RS485 bus — more properly termed TIA-485, following the abandonment of the "Recommended Standards" prefix and the dissolution of the EIA which originally mandated the label — supports data rates up to 20Mb/s with speed-distance trade-offs allowing for connection distances as long as 1.2km (4,000 feet). Popular in industrial environments for its resistance to electromagnetic interference (EMI), RS485 remains a popular standard — and Jetpack Cognition Laboratory's latest shield makes it easy to add Arduino Nano boards to any RS485 bus.
Designed, the Lab claims, owing to a lack of suitable RS485 add-ons for the compact breadboard-friendly Arduino Nano development board - and the lack of safety built into what few suitable designs do exist. "In comparison to other (cheap) RS485 breakout boards, this one uses a high-quality ESD protected and fully fail-safe RS485 transceiver and perfectly fits onto an Arduino Nano (or compatible) board," the Lab explains.
"Further advantages are: The shield provides a separate voltage regulator and your Arduino and peripherals are directly powered from your bus with up to 15V, 500mA; you can place an optional termination resistor, which is usually 120 Ohms, but maybe different for your specific bus transmission line or power specification; you have two connections on the board to simplify daisy-chaining."
The Lab is selling the shield as a fully-assembled and tested PCB with surface-mount components and sockets, along with a termination resistor — the latter to be placed at the end of a daisy-chain network to reduce reflections — priced at $18.60. Those looking to bring the price down have the option of receiving a self-solder kit at $14.27, or to leave off the connectors to bring it down still further to $13.37.
More details are available on the Tindie product page.