5V 2-Channel Relay Module Shield for Arduino ARM PIC AVR DSP Electronic ( £1.50 on 8/4/2017)
https://www.amazon.co.uk/gp/product/B00CRVYIMG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Diagram:
Vcc=JD-Vcc = + 5v
IN1= GND ( LED= ON, and relay= switch over)
