Parts List

I bought all these items on eBay, from China. Order early, look for free shipping.

Arduino Uno

ATmega328P CH340G UNO R3 USB Driver Board For Arduino w/ USB Cable $6.50

Relay

2-Channel 5V Relay Module With Optocoupler For Arduino $3.98

(you will only use one channel)

Solenoid

DC 12V 0.4N Push-Pull Open Frame Solenoid Electromagnet $4.13

DC Power Plug

DC Power Plug + Socket 2.1mm x 5.5mm Male + Female Connector set $0.99

9V Battery Adapters

2pcs 9 Volt 9V battery adapter for Arduino $0.99