Full instructions and code here: http://blog.rniemand.com/monitoring-reed-switch/
This is a simple reed switch enclosure with a case built specifically for a D1 Mini ESP8266 module accompanied by buck converter. This is ideal to hide inside a roller gate motor (and be powered off the 12v battery) to provide alerts when it opens.
Print head: 210
Print Bed: 50
Print Speed: 50-60