enter image description herethe M7404 Hex inverter is used to send an active low signal from a PIR sensor to a microcntroller pin

However the reset is being constantly sent some signal keeping it set to on. You can tell because the reset light is on in the picture

Thanks to ST2000 I was able to figure out I need a hex inverter open collector to change the high signal from high to low because the reset pin on the microcontroller is active low. However, Whenever I use the active low reset pin (number 3 on the esp32) it goes into a state of holding down the reset button. Or constantly being high. Here is the thread where ST2000 was able to provide me the solution I am working on: esp32 cam and PIR sensor

Here is a schematic of my wiring to the esp32 reset pin from a PIR snesor using an inverter in between

My question is: how do i get the pir sensor to send an active low signal to the microcontroller?

here is a schematic of the esp32 board https://i.redd.it/yv050peu22p21.png

  • Ok i tried my best to make a schematic and updated to include a question sry. @jsotola – David Graff Jun 25 '19 at 19:49
  • That schematic makes no sense. – Majenko Jun 25 '19 at 19:55
  • The data line from the pir sensor goes through the inverter and then into the microcontroller that is supposed to accept an active low to trigger reset on the board. I know it doesnt make sense but please bear with me or provide another site that is easier to make schematics. – David Graff Jun 25 '19 at 20:00
  • Edit your question then press the schematic button. – Majenko Jun 25 '19 at 20:15
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    If you want to turn your active high output into an active low one all you need is a transistor and a resistor. The transistor makes it active low and open collector, and the resistor pulls it up to 3.3V. – Majenko Jun 25 '19 at 20:19

I wouldn't have chosen a hex inverter for this job. I'd have just used a transistor and a resistor:


simulate this circuit – Schematic created using CircuitLab

When OUT is HIGH, M1 is ON, which connects D3 to GND. When OUT is LOW, M1 is OFF, which allows R1 to pull D3 up to 3.3V.

As to why you have a boot loop, now you have shown a slightly (though still confusing) clearer schematic I can tell you that it is because you are using pin D3.

Don't use pin D3.

D3 is the RX pin and is held HIGH at boot. That means that when the board resets D3 goes HIGH which then pulls reset LOW through your inverter, which then lets D3 float, so RESET goes HIGH, and that makes D3 then go HIGH which means the RESET is pulled LOW... ad infinitum.

You should read this page and choose a different GPIO pin that isn't going be doing things at bootup.

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