Every facility has a conference room or other meeting space. And when the door is closed, it is always a guessing game whether the room is occupied or not. This inevitably leads to someone opening the door and disturbing what is happening inside. It could interrupt a meeting or spoil an important experiment.
Commercial sensor/indicator combinations can cost over $400 dollars. If you have many rooms, the cost could be prohibitive.
This project started as an inquiry by the Indiana University IT Department who wrote to Adafruit asking if there was a less expensive alternative to commercial units by using Adafruit’s Trinket mini-microcontroller. This project is inspired by that inquiry.
The small weatherproof enclosure is a good sized enclosure for the project. The 1/2 sized Perma Proto Board fits inside the box and clears the rounded divots with a bit of modding..
The 2.1mm panel mount barrel jack is used for power – solder power wires on prior to installation (large lug is positive). Drill a 1/2 inch hole just past the cover hole. The plastic dimple was chisled to fit it in that location. Thread the jack in securing with the included plastic screw ring. A cable gland is used to run the PIR sensor wires through the enclosure keeping things weathertight. Drill a 5/8 inch hole (for the large gland, a smaller if you use the small gland) between the power jack and the other case cover hole. There is a small lip on the case – I dremeled it down a bit to have the gland fit snug. You can run penetrations through the back as an alternative if you want the look to be “cable free”.
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