EcoRenovator - Radar sensors boards 57 cents.. (if you buy 5)

https://www.ebay.com/itm/Top-1-2-5-1...d/172936588667

These put out 3.3 volts (semi-TTL "1") when they sense movement.
I had one SSR that can use 3 to 15 volts for a trigger, and it works with the Radar..
It stays on, if you keep moving around. If you stop cold, it turns off within a couple of seconds..
Info pdf: https://www.tayloredge.com/reference...cs/RF/0242.pdf

I understand the range/sensitivity can be turned down by adding a SMD resistor.
That might be needed for my 1st install. It's too sensitive.
The 120vac LED work lamp it's controlling is in the basement, (unfinished ceiling),
and whenever anyone walks around in the living room upstairs, it turns on.. :o
The LED & the Radar are mounted on basement overhead 2x8 boards..
I tacked some 10"x16" copper sheet up above the Radar and it's still too sensitive.. :eek:

It works and my wife really likes not trying to reach up to the ceiling for the light switch.

Anyways, I'm thinking of using one of these Radars as a Visitor sensor.
Install it next to the front door, (under the siding) and have it sound a beep-beep if the signal stays on '1' for more than for more than a few seconds.
It could be connected up to an ESP8266 that would monitor the "1" time (for beeping),
and also be setup like the garage doors, off/on controllable by Amazon Alexa.
It would be nice to know when a delivery is dropped off on the front porch. ::D
It could run on a schedule from an Alexa 'Routine' scrip. Staying off late at night,
when the coyotes are chasing rabbits around the front porch.

One other idea for use in a car. I'm wondering how they would work as a Deterrent LED flasher, when someone got within 15 feet of your parked car.?.

They only use 0.0135w (2.7 MA at 5V) so they look easy on a 12v car battery..
https://youtu.be/9WiJJgIi3W0?t=14m49s

https://github.com/jdesbonnet/RCWL-0516

There are 3 unpopulated Pads on the backside of the PCB.

C-TM Regulate the repeat trigger time. The default (unpopulated) time is 2s. A SMD capacitor to extend the repeat trigger time.
Pin 3 of the IC emits a frequency (f), and the tigger time in seconds is given by (1/f) * 32678

R-GN The default detection range is 7m, adding a 1M resistor reduces it to 5m

R-CDS the VCC is in parrel connection with CDS(RCWL-9196 pin 9) through R-CDS. Connect the LDR at the R-CDS to turn off the detecting function at night. (?? TODO: make sense of this)