That doesn’t make any sense on a digital out. All what it will do it decrease the the signal voltage to a level that cannot be reliably recognized by the MCU as a binary high anymore. It will not reduce false triggers, it will simply miss them. It will also miss legitimate triggers.
The main problem with the RCWL is it’s extreme sensitivity to wifi. Having a wifi transceiver nearby, such as an ESP, will cause huge problems. And ‘nearby’ can be over a meter away, in more extreme cases. I could bet that nine out of ten cases where people report false trigger problems with this device, it is wifi interference. I have a setup with an RCWL monitoring a walkway outside, and it works flawlessly. It uses wired Ethernet with PoE and an Arduino. There’s also a metal shield just in case.
Here are some tests I did with this device in the lab. In addition to the usual connections, I soldered a wire to the chip directly, so to get the analog signal before the comparator and see what goes on in there:
The analog signal level is kept at a constant reference level if there is no movement. When an object approaches the sensor, the voltage will increase. And it will decrease from this reference level when an object moves away from the sensor. As soon as the voltage deviates from the reference bias, a compensation circuit kicks in and forces it back to the reference level. The amount of compensation is proportional to the rise time of the original signal level change. So a fast movement will trigger a fast compensation and vice-versa. The compensation can (and will often) overshoot before it compensates itself. This is why the analog signal fluctuates so much up and down even with linear motion towards the sensor. As soon as the signal deviates too much from the reference level, a comparator will trigger the digital output high. It goes back to low with some delay after the analog signal reached the reference level again.
The yellow channel is the digital out, the blue channel is the analog one from the chip.
A - I start moving towards the sensor. The analog voltage increases, goes over the threshold and the digital output triggers.
B - The compensation kicks in and draws the voltage back to the reference. This process repeats multiple times until I stop moving.
C - I stopped moving and the compensation slowly brings the analog signal back to the reference level.
D - The internal delay was reached without movement and the digital output goes back to low.
Now I created a wifi hotspot on my mobile phone. I put the phone on the desk, 30cm from the RCWL. I asked a colleague to connect to the hotspot with a tablet from an office across the hallway. This is what happened:
You can clearly see the Wifi signal appearing in the analog signal. The first peak was too small to reach the threshold of the comparator, but the second one triggered the digital output. This was with a wifi transmitter (my phone) 30cm away from the sensor.
Now I put the phone 1 meter away from the RCWL. I also disconnected the tablet from its AP and just let the AP idle. It will still advertise its existence every so often. And it will still create false triggers:
The peak in the signal is lower, but the wifi transmitter is now 1 meter away. It’s still enough to trigger the comparator and as such a false trigger.
So as far as I see it, there is no way to use this sensor in combination with any MCU that emits a wifi signal in any reliable way. It might work sometimes. But you can never be sure.
This is my own little quick and dirty test setup with the sensor at home. Works really well, no false triggers in over a week. But as I said, it’s entirely wired and connects to HA over MQTT. It monitors a walkway outside through the window, sensitivity is around 7m.