> For the complete documentation index, see [llms.txt](https://brlabelectronics.gitbook.io/hardware-1/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://brlabelectronics.gitbook.io/hardware-1/functional-description/overview.md).

# Overview

The Boron-Argon Relay Shield 4-Channel is the next-gen accessory for the third generation particle devices. This relay shield is designed to work with the Particle Argon Wi-Fi development board and the Particle Boron LTE development board. The Boron-Argon Relay Shield can operate off of a 12VDC supply or from a 3.7-4.2V lithium ion or polymer battery. This makes this a great board for controlling systems that are remote or off the grid. Mount-ability and packaging was kept in mind while designing this board. Using a DIN rail mount housing makes this board DIN rail mountable. This is perfect for mounting it inside of electrical cabinets, electronic control boxes, or industrial machinery. 

Two power supplies can be connected to the board at the same time - the 12VDC supply and the battery supply. Both the Boron and the Argon have a power management IC that determines which power supply to use. For example if the main power supply (12VDC) is lost, the board will know to switch to the battery as a backup power supply. The battery will supply the entire board with power, as there is switching logic and a boost converter to supply the board with 5VDC and 3.3VDC. The 12VDC can be supplied in two different ways - by the 2 position screw terminal or by the 2.1mm barrel jack as found on the Arduino Uno and Mega2560. The battery needs to be plugged in directly to the development board; then the USB cable that is supplied with the development board needs to be plugged into the vertical USB-A connector on the relay shield and the micro USB-B connector on the development board. This is how the development board is supplied with power and can charge the battery when the power management system determines to do so. 

The main functionality of this board is to switch four individual power relays on or off. Each relay has a screw terminal block for breaking out the relay pins. The other digital I/O, analog I/O, and communication pins of the development board can be accessed via pin headers or screw terminal breakouts.