Homemade Motion Sensor

This is an extension of my project for Homemade Environment Sensor. The sensor is now expandable. I am creating a new thread to share on how I extend the sensor.

This week, I just got shipment for a motion sensor. There are a lot of discussion about PIR based motion sensor. I would like to share my experience with microwave radar based sensor. The product id is RCWL-0516. You can search it on Ebay or Aliexpress. They can be purchased for less than one dollar. Here is how it look like.

This kind of sensor typically have 360 degree coverage. It also does not need line of sight. This is could be an advantage for right application.

Here is a short demonstration.


I also have a good old PIR sensor. It is hc-sr501 motion sensor which also available in Ebay and Aliexpress for less than one dollar.

This sensor is really hard to use in outdoor environment. It has a lot of false positive due to cloud and sun.

So, I combine the hc-sr501 & RCWL-0516 like below.

The PIR sensor is the primary detector in this case. When it detect a motion, it will enable the cds pin on RCWL-0516. At that point, if RCWL-0516 detect a motion as well, then the vout pin on RCWL-0516 will output a binary one to indicate a motion. Doing this will reduce the false positive when you use a PIR sensor outdoor.



Now you just need to 3D print a case for it. :smile: and then maybe sell it here for those that want a more accurate outdoor motion sensor.

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I am not able to produce in large quantity. However, whenever I have to build the sensor modules, typically, I have more than I can use. In my original thread, I have shared them with members here. In return, I have requested donation for the project.

I use donation to buy more part and make more revision to the board. I did have a manufacture in China to build 10 unit. It was so expensive. I just want to test them whether they can build the sensor with good yield. The good news is that they can do much more superior job than I can in assembling the sensor. The bad news is I blew all the donation fund on that trial run. They are expensive. The only way to get something reasonable is to have them build in much larger quantity.

In the long term, I am considering a case. Many people ask about the case. Case complicate things with temperature sensor. There are many battery operated temperature sensor. They sleep most of the time. Putting them in the case had negligible impact. My design require the MCU run all the time for the Zigbee Routing capability. This has heat implication. Please do not get me wrong, the MCU is not like a PC or Fireplace. It does generate give and take about 4 to 6 degree Celsius offset in a case. This is a solvable using isolation compartment. However, I am not ready to deal with this kind of design work yet.

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Thank you very much @iharyadi.

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