RPi Relay Board: A Raspberry Pi smart home expansion board that costs just US$18.99
Have you ever thought about using a Raspberry Pi to control your home appliances? Well, the RPi Relay Board would allow you to do so without having to spend huge amounts on smart devices. The RPi Relay is an expansion board for the Raspberry Pi A+, B+, 2B, 3B and 3B+ that can handle high currents and voltages, which would typically overwhelm the popular developer board.
The RPi Relay supports up to 5A/250V AC or 5A/30V DC and uses optoisolators to prevent interference from high voltage circuits. The expansion board has three relay channels for connecting devices along with LEDs for indicating which relays are active. Moreover, Waveshare has included a GPIO and screw holes for connecting and mounting the RPi Relay to a Raspberry Pi.
Waveshare has published an extensive wiki too with development resources for BCM2835, python, shell, WebIOPi and WiringPi. The RPi Relay Board is available to purchase on Waveshare for US$18.99, which ships worldwide. The company also offers bulk pricing that effectively reduces the cost to US$17.49 per unit if you buy 4 or more boards. Alternatively, you can currently buy the RPi Relay Board on Amazon US for US$21.85 including a 6% discount.