Proximity vs Microwave Radar
I discovered that the proximity had a limited proximity to detection of only a few centimeters and did not successfully net my end goals for the backpack. After extensive research, I found that other DIY individuals found great success with their projects utilizing microwave radar sensors. I search for the best inexpensive radar on the market and stumbled on the WHDTS 2.25GHz microwave radar detector module with a detection range 6 to 9 meter. This would prove to be exactly what I needed to and it would also change the name of my project to the microwave radar backpack.
The XYC-WB-DC microwave chipset comes with several dedicated resistors, transistors and power regulator. The microwave radar works by sending out microwave signals that detect the movement of an object within its field of view when the signal is bounced back to the radar.
Humor: I began to solder my components and discovered that my soldering iron was no longer working. After I tried unplugging, cleaning, and moving the heating element around, I decided to take the iron apart. I discovered that one of the wires connected to the heating element was disconnected. I taught myself;” How do I solder a soldering iron?”. Yup, it happens, but I was able to firmly push it back together and it soon started to heat up again.
I found some test code for XYC-WB-BC and I was able to check the accuracy of the radar. I discovered that the XYC-WB-BC was under-powered and unable to detect anything within its prescribed specs of 6 to 9 meters. Instead, I got a constant register at approximately 12 inches from the sensor using the serial monitor with the Arduino software.
I now needed to figure out how to achieve the 6 to 9 meters of detection that was guaranteed by WHDTS. I found a fantastic video on youtube by Blair Thompson, ‘Modifying an XYC-WB-DC Microwave Motion Sensor for use in a Sonoff SC’, that illustrates how to basically give the chipset a boost. He adds a variable Bournes 0-100k resistor to his modification. I discovered that adding the variable resistor would not be necessary to achieve a 6-meter distance with this modification (in his defense, he does state that adding the variable resistor was over-kill).
Now, that I have my modification done, I was able to utilize Blair’s code to check the radar with the Arduino Uno. Blair’s code basically states that if the radar triggers then the LED pin 13 will go high and lights up and prints to the serial bus. If the sensor goes low then it turns the LED off.
I am happy to report that this was a successful test. Here's the link to his video: https://youtu.be/41rf6NbuhBs and here is the link to the test code: https://github.com/Justblair/microwaveTester. Thank you, Blair.
I soldered together two microwave radars with the intention of creating a 360-degree field of visual stimuli but I was running short on time and was unable to add the second radar. I am including a video that illustrates putting it together.