Quantity   Component name
1 × IOT Cricket - Wi-Fi module https://thingsonedge.com
1 × Door Window Magnetic Switch https://www.amazon.co.uk/sourcing-map-Magnetic-Security-Normally/dp/B00PZMG980/ref=sr_1_8?dchild=1&keywords=Reed+Switch&qid=1590006223&sr=8-8
1 × Battery Holder https://www.amazon.co.uk/HALJIA-Battery-Storage-Organizer-Container/dp/B07MSFXVFJ/ref=sr_1_4?dchild=1&keywords=aaa+battery+holder&qid=1590006305&sr=8-4
1 × 2xAAA batteries