Connecting an old wired PIR to ESPHome

ESPHome
1

Hi,

I have recently taken on my first ESP32 and ESPHome project. I have an old security system installed in my house, where most of the hardware was removed before I purchased the property. What was left was 14 cables terminating in my utility cupboard. This includes 8 PIR sensors, 3 Door contact sensors, an entryway keypad, an internal audio alarm and an external audio and visual alarm.

The system was originally powered by a cable with 6 cores, color-coded as black, red, white, green, blue and yellow.

The PIR sensors are connected as follows:
+: Red
-: Black
C: White
NC: Green
T: Blue
T: Yellow

My thinking was, I install a 60w 12V5A power supply in the utility cupboard and use this to power all of the devices with 12V power. I then have a 5V regulator connected which powers the ESP32.

I have successfully installed ESPHome, and flashed my ESP32 with a YAML file that means it appears within Home Assistant.

I can get a motion sensor to show in Home Assistant, and to flick between Clear and Detected when I connect a wire to GPIO4 and switch it between 3.3v and GND. This meant the ESP32 is working as expected.

What I am having issues with it getting the PIR sensor to output a singnal from its C or NC connection that the ESP32 can recognise. The PIR is Normally Closed (which I verify using the continuity setting on my multimeter, it beeps when no motion is detected, and doesn’t when motion is detected).

The PIR is the Honeywell IS-215QT (chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.sourcesecurity.com/datasheets/honeywell-security-is-215tq/co-2173-ga/is2125tqdatasheet.pdf)

The label shows - and + as 12 VDC 10mA, the C and NC as 16VDC 90mA and the Tamper as 30 VDC 0.5A.

I have tried changing between INPUT_PULLUP and INPUT_PULLDOWN without success, and am assuming it is my lack of understanding of electronics meaning I am not clear on what connects to what. I have tried resistors between the C and GPIO 4 to take the Voltage down to 3.3V, but this hasn’t helped.

Please see my rudementary diagram below. I am actually now using an ESP32-C3-MINI, not a C6.

Screenshot 2025-01-28 at 10.02.20
Screenshot 2025-01-28 at 10.02.202458Ă—2000 268 KB

Any help or advice would be appreciated. I am completely new to electronics, so my knowledge is limited.

2

C to the ESP ground.

NC to the GPIO.

Enable pullups.

1 Like
3

Thanks for the quick response, I have now tried this.

The sensor in Home Assistant is now switching between Clear and Detected multiple time (20ish) a second, regardless of if motion is detected or not. This continues even if the PIR sensor is not powered, but the ESP32 is (via USB).

The

Screenshot 2025-01-28 at 10.55.41
Screenshot 2025-01-28 at 10.55.411348Ă—996 89.2 KB

4

Then either you have wired it incorrectly or you have a lot of electrical noise induced onto your cabling. Try a 0.1uF capacitor from the GPIO to ground as well.

5

Thanks for you reply. I have double checked my wiring and all seems as you said. I only have resistors at present, but have some capacitors arriving tomorrow, so will try then.

6

Post your yaml.
Sounds like you don’t have pullups set.
Also, you can use esphome sensor filters to eliminate noise.

1 Like
7

Though it is better to eliminate it.

1 Like
8

Of course.
Also we don’t know anything about the physical wiring.

1 Like
9

Here is my YAML.

binary_sensor:

  • platform: gpio
    pin:
    number: GPIO4
    mode: INPUT_PULLUP
    name: “PIR Motion Sensor”
    device_class: motion

Unfortunately I don’t have much experience with ESPHome yet, so not sure how to use sensor filters to eliminate noise.

Happy to post a picture of my wiring if that would help troubleshoot the issues.

10

If you don’t use code tags, no-one can tell if your indentations are correct’


binary_sensor:
  - platform: gpio
    pin:
      number: GPIO4
      mode:
        input: true
        pullup: true
    name: “PIR Motion Sensor”
    device_class: motion
    filters:
      - delayed_on: 10ms
1 Like
11

I will test your code.

typbinary_sensor:
  - platform: gpio
    pin:
      number: GPIO4
      mode: INPUT_PULLUP
    name: "PIR Motion Sensor"
    device_class: motion