1. Seeed Studio 2-Channel SPDT Relay: This low power, low cost 5V relay module is ideal for switching electromechanical loads. It can handle loads up to 10A and has an operating voltage range of 3 to 11V. The relay is protected by a covers to avoid any contact with live parts and the module is provided with a selectable LED status indicator. The two channels can be used electrically or mechanically isolated to provide two independent switching paths with a choice of SPDT contacts. Also, this relay can be controlled via TTL signal or a DC voltage.
2. Seeed Studio 2-Channel SPDT Relay with DIY Breakout Board: This module includes an onboard relay driver, along with a breakout board to use with any signal or power source. An on-board diode protects the driver from voltage spikes. Also, this relay module is provided with a power LED indicator and LED meaning the current state of each channel. The relay is compatible with 5V and 12V DC inputs, and is compatible with 3.3V and 5V TTL signals.