I found myself recently looking into the best (cheap) way to create a distributed presence/motion detection network. I've been using basic PIR Motion detectors for the past couple of years and while they do work fine in most situations there is still a lot to be desired... Ease of use and appearance to name a couple.
PIR's work by bouncing around infrared signals, these signals cant pass through solid objects. That's why most TV remotes only work while pointed directly at the receiver. Due to this limitation of the technology, the PIR's themselves have to be relatively visible and placed somewhere prominent in a room.
On the other hand, radar motion detectors use microwaves which can easily pass through most solid surfaces and walls. Perfect for a 'hidden' whole house motion detection network. As well as this obvious improvement the radar module I use (RCWL-0516) is almost 4 times cheaper!
One of the most important factors for this project was to be as cheap as possible while still having 'nice to have' extras, such as having a temp and air pressure sensor included. I will provide a parts list to help anyone who is interested setting something similar up.
Roughly $2.90 USD
Assembly process can be seen in the images provided. Each part has to be placed in order for everything to fit. If anyone is confused don't hesitate to ask your questions in the comments.
Anyone who would like suggestions on ways to use these sensors in a network my recommendation would be ESPHome (https://esphome.io/). The modules can then be linked to Home Assistant (https://www.home-assistant.io/) for easy management and monitoring.
The STP file is also provided for anyone who wishes to make changes.
| ESP01_Standoff.stl | 2.6KB | |
| ESP_Radar_Module.step | 1.6MB | |
| Module_Case.stl | 87.0KB | |
| Module_Lid.stl | 10.8KB |
