This IoT 2-channel low-power signal relay controller is capable of hosting many types of IoT communication modules, including Particle Photon, Electron, Arduino, and more. On-board SPDT relays are ideally suited for low-power signal switching applications, up to 1 Amp at 12VDC. NCD SPDT relay controllers have three connection terminals for user-access to each relay. We use high-quality Omron relays with a low on-resistance between contacts. Designed primarily for resistive or mildly capacitive low-power signals, the on-board relays in this design focus on signal integrity, making it an ideal choice for telecommunications and low-power audio switching applications.
This controller is based on the MCP23008, a common I2C interface chip for GPIO applications. In this design, the GPIO port is used to control 2 on-board SPDT relays. Six programmable Digital Input/Output port pins are also available via screw terminals for use in Contact Closure detection applications or monitor and control external TTL circuits. Three on-board address jumpers allow up to 8 similar devices (based on the MCP23008 or MCP23017) to be chained to the same I2C bus for individual control. On-board status LEDs display the on/off status of each relay. This controller may be powered using our optional power supply or with 12VDC and direct screw terminal connection of bare power wires. Each relay is accessible to the user via screw terminals, capable of accepting 14 AWG wire.