Rigging dumb driveway sensor with Fibaro Smart Implant?

Hardware
1

I have a Fibaro Smart Implant and a generic dumb driveway sensor I’m trying to make smart. Thought I had it working but realized I wired it slightly wrong and now that its correct I get no proper signals, again didn’t do it right so want to get some ideas for what to add to fix the issue.

Driveway hub supports 4 sensors, each with their own LED that blinks when motion detected. It runs on 5v/6v via 4 AAA’s.

Planning to tap into the LEDs for each of the 4 driveway sensors with some debounce for blinking.

Fibaro runs on 9-30v and has 2 INPUT signal wires I’m trying to use.

Wrong way

Initially I wired it wrong by tapping both sides of LED for signal & ground as opposed to ground from battery and signal from input side of LED.

That setup got 0v on no light and 1.5 when one was blinking. But because “shared ground (NOT GROUND)” one light signaled both wires the same.

I got a proper detectable signal on INPUT1 from the Fibaro, seemed to work, but INPUT2 didn’t.

Rewired

Rewired to have shared ground with hubs battery, and one signal wire from each LED on proper side. Both get a proper voltage ~1.5v when activated as expected now.

Fibaro Issue

Fibaro firmware is terrible and is causing ~0.8v constant voltage out on the INPUT line now when not in ANALOG mode. Only if I put them into Analog mode will it go to 0 when passive, but then it doesn’t detect properly as the spikes in voltage to blink the LED are too short or don’t occur during polling (I’m guessing).

When not in analog mode the voltage being 0.8v causes it to never detect an open circuit or change when 1.5v is applied.

Does anyone know why that 0.8v is applied constantly? Haven’t found definitive answer, or is this unit a dud?

The Plan

My plan which I’m hoping to get validated is to somehow convert that 0-1.5v to a usable digital signal acting more like an alarm door open signal

Will using either a ADC (Analog to Digital Converter) or some type of relay to convert the analog ~1.5v+ into a digital signal that the INPUT can properly asses.

Also plan to add a static 9v source & 6-24v → 5v DC buck converter to power the hub and ditch the batteries.

Does that sound like it should do what I need. I think my issue was wanting a digital signal, but getting a blinking LED is not exactly that.

2

I’m not really familiar with the Fibaro device you mention. I have a similar sounding driveway alert device from Swann. I wired the blinking leds to a wemos d1 mini left the batteries in the Swann receiver and power the d1 through a usb cable. I think a d1 mini would suit your situation just fine. No need for worries about all this voltage conversion and digital and analog stuff. There are some videos online that showed me how to figure this out.

3

Without looking into it too deeply you could probably create a voltage divider circuit with two resistors such that you sink that 0.8V to ground.

4

In analog mode fibaro does not report voltage in inputs as it changes. You have to refresh node value to get reading.I use smart impants for car presence detection using Sharp IR distance sensors and it work fine, but I had to create automation to refresh node values for analog inputs every few seconds. Otherwise it remains constat at last reading. I think that with Z-Wave JS it is possible to change some configuration parameters (Fibaro Smart Implant FGBS222 - Hardware - Home Assistant Community (home-assistant.io)) so these gets updated, but due to voltage fluctuations I’m afraid to have HA flooded with lots of frequent updates, so I did not tested this solution.
Regarding 0.8V on Input… this might be normal as device must somehow recognize closing the connected swith and this is done by shortcutting input to the ground. Then voltage drops to 0V and this is recognized as switch closed.

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