MQTT seems slow, unsure what next to troubleshoot

Installation Home Assistant OS
1

Rather new to home automation, home assistant, Zigbee, MQTT, the lot. I might have a problem with MQTT. Or not.

My setup is a RPi 4B/2Gb/wired ethernet/ Raspbee(=Conbee) with Hass.io. 5 Trådfri bulbs. That’s all working quite nicely.

I have Raspberry Pi Zero (on wired ethernet) with a DHT sensor and a PIR sensor. And I have Mosquitto broker on a separate Raspberry Pi Zero W.

The sensors are working, I can send readings/detect motion and see both appear as MQTT messages on the broker and in HA.
I added an automation to HA (my first) to change the lights when movement is detected. It’s working…but…

It takes 5 seconds between the PIR being triggered and the MQTT msg to arrive at both the broker and HA. At first I suspected the Wifi, but after connecting the broker to wired ethernet, it’s the same. However, when I Publish a message from HA, it arrives at the broker instantly.

I’m unsure if the 5 second delay would be a real problem, although I can imagine 5 seconds is rather long for me, when half asleep stumbling into the bathroom in the middle of the night. For now, however, I just want to understand what’s going on, what’s causing the problem.

Any ideas/suggestions?

2

Maybe it’s your PIR? Try triggering the input pin on the DHT / movement Pi zero and see how long it takes to arrive at the broker.

I’m using many PIRs connected to a pi3 running this and it’s virtually instant.

3

I don’t think it’s the PIR; i added a buzzer (should have mentioned that!) as an audible indicator. Between the beep (thus the PIR detected motion) and the msg arriving at the broker (and HA) there’s this 5 seconds delay.
…Just tested by removing the PIR and making the GPIO high by manually connecting it to 3.3V. The beep is instantly, the msg arrives 5 seconds later.

I also changed the GPIO pin, but same result: 5 seconds delay.

Additionally:
The Raspbian version I’m using is the full version; I just tested with the latest light version, but the delay remains the same.

4

So it’s whatever you are using on the pi to publish to the broker then?

You could try the program I linked to above. Very easy to configure. Just a YAML file.

5

I’m using Python/paho.mqtt. My code:

# PIR/MQTT test

import sys
import RPi.GPIO as GPIO
import paho.mqtt.client as mqtt
import time

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

# inits
MQTTBroker = "192.168.1.180"
MQTTpTopic = "RPiDevW/Motion"
# BuzzerGPIO
GPIOBuzzer = 21
# PIR GPIO
GPIOPIR = 20

GPIO.setup(GPIOBuzzer, GPIO.OUT)
GPIO.setup(GPIOPIR, GPIO.IN)

# MQTT Publish
def on_publish(client,userdata,result):
    pass

while True:
    time.sleep(2)
    if GPIO.input(GPIOPIR):
        GPIO.output(GPIOBuzzer, True)
        time.sleep(0.1)
        GPIO.output(GPIOBuzzer, False)
        Msg = "(E)Motion!"
        print(Msg)
        time.sleep(5)
        client1= mqtt.Client("control1")
        client1.on_publish = on_publish
        client1.connect(MQTTBroker,1883)
        client1.publish(MQTTpTopic, Msg)
    time.sleep(0.1)
6

Duh. And a big one at that!

I just pasted the MQTT code into my PIR-test code…and completely missed the time.sleep(5) in there, just before publishing the MQTT message.

Fixed! All is working working as intended now, near instant lights-on when motion is detected.

Thanks for thinking along!