Wire multiple SW-420 sensors to a single pin

I am working on installing an alarm system using Konnected IO on a NodeMCU esp8266. I have multiple bay widows which will use 4 SW-420 vibration sensors. I would like to wire all 4 of the SW-420 vibration sensors to a single pin. When any of the 4 sensors detect vibration the pin will go to high. I attempted to simply wire the d-outs from all four together and all four sensors stoped working. I’m out of ideas on how to do this any help would be greatly appreciated. I believe sensors send out a low signal when no vibration is detected and high signal when vibration is detected. Link to sensors: https://www.amazon.com/XLX-Vibration-Normally-Sensitive-High-Efficient/dp/B07V8FJRN1/

Hi,
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I am working on installing an alarm system using Konnected IO on a NodeMCU esp8266.
I have multiple bay widows which will use 4 SW-420 vibration sensors.
I would like to wire all 4 of the SW-420 vibration sensors to a single pin.
When any of the 4 sensors detect vibration the pin will go to high.
I attempted to simply wire the d-outs from all four together and all four sensors stoped working.
I'm out of ideas on how to do this any help would be greatly appreciated.
I believe sensors send out a low signal when no vibration is detected and high signal when vibration is detected.
Link to sensors: https://www.amazon.com/XLX-Vibration-Normally-Sensitive-High-Efficient/dp/B07V8FJRN1/

Spec of device;

Sensor performance and features:

  1. Adopt SW-420 normally closed type vibration sensor.
  2. The comparator output, the signal is clean, the waveform is good, the driving ability is strong, more than 15mA
  3. Working voltage 3.3V-5V
  4. Output form: digital switch output (0 and 1)
  5. With fixed bolt holes for easy installation
  6. Small board PCB size: 3.2cm x 1.4cm
  7. Using a wide voltage LM393 comparator

Have you got one device to work?
Do you have a DMM to measure the output of the sensor?
Tom... :slight_smile:

As above, get one working and then look at multiplexing them. Various methods exist from a diode on each output to a 4 input NOR / OR gate.

Use a simple diode or circuit: The pull down resistor is mandatory otherwise it will not work. Start with something in the range 10 1K. You can expand this circuit to as many inputs as you want, within reason. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil

Thank you guys for the help. I do have a DDM and was able to get a single device to a single pin working properly prior to posting. I attempted to google and searched for hours over multiple days for an answer prior to posting. It seems I may have not been searching the correct terms due to a lack of knowledge on the electrical side. I am a software engineer by trade and just recently began to get into the hardware side of things. Gilshulz answer helped me to get it working. Thank you everyone for taking the time to reply to my post and for the assistance resolving this problem.

The problem here is that you were using the "HILETGO" module:

which is active-HIGH on an open-collector output from the LM393, instead of the "Grove" module:

Zoom!

which is active LOW.

With the Grove module, you can in fact, connect the outputs of multiple modules directly together.

Note that the resistor in gilshultz' diagram should be a reasonably high value - more than 22k - as the main pull-up in the "HILETGO" module is 10k though the LED does also pull-up but this would be marginal with a 3.3 V supply. The diodes and resistor must be mounted close to the ESP8266 due to the high impedance at this point - which may cause problems with long lines to different windows. :astonished: