MMM-Temperature uncaught exception...

[Brown19]

I wrote a script to use the SHT31-D temperature and humidity sensor from adafruit. The script works in that it correctly displays the temp and humidity. The log file however shows the following:

[02.08.2023 19:53.15.002] [LOG] MMM-Temperature: Updating sensor values
[02.08.2023 19:53.15.002] [LOG] MMM-Temperature Calling: /home/mpi-admin/MagicMirror/modules/MMM-Temperature/scripts/sht31
[02.08.2023 19:53.15.338] [LOG] {“temperature_c”:24.78637369344625,“humidity”:42.03402761882963,“temperature_f”:76.61547264820325,“error”:false}
[02.08.2023 19:53.15.339] [LOG] MMM-Temperature: New Values of sensor with id 0 (Indoor): {“temperature_c”:“24.8”,“humidity”:“42.0”,“temperature_f”:“76.6”,“error”:false,“temperature”:“76.6”}
[02.08.2023 19:53.15.339] [LOG] Sending temp update: [{“temperature_c”:“24.8”,“humidity”:“42.0”,“temperature_f”:“76.6”,“error”:false,“temperature”:“76.6”}]
[02.08.2023 19:53.15.346] [ERROR] Whoops! There was an uncaught exception…
[02.08.2023 19:53.15.362] [ERROR] Error: write EFAULT
at afterWriteDispatched (node:internal/stream_base_commons:160:15)
at writeGeneric (node:internal/stream_base_commons:151:3)
at Socket._writeGeneric (node:net:930:11)
at Socket._write (node:net:942:8)
at writeOrBuffer (node:internal/streams/writable:392:12)
at _write (node:internal/streams/writable:333:10)
at Writable.write (node:internal/streams/writable:337:10)
at execSync (node:child_process:981:20)
at node:electron/js2c/asar_bundle:2:12711
at Class.updateSensorValues (/home/mpi-admin/MagicMirror/modules/MMM-Temperature/node_helper.js:65:24)
at Class.socketNotificationReceived (/home/mpi-admin/MagicMirror/modules/MMM-Temperature/node_helper.js:165:12)
at Socket. (/home/mpi-admin/MagicMirror/js/node_helper.js:104:11)
at Socket.emit (node:events:513:28)
at Socket.emitUntyped (/home/mpi-admin/MagicMirror/node_modules/socket.io/dist/typed-events.js:69:22)
at /home/mpi-admin/MagicMirror/node_modules/socket.io/dist/socket.js:703:39
at process.processTicksAndRejections (node:internal/process/task_queues:77:11) {
errno: -14,
code: ‘EFAULT’,
syscall: ‘write’
}

This is my script:

#!/usr/bin/env python3
#Install Dependencies:
#  cd ~
#  sudo pip3 install --upgrade adafruit-python-shell
#  wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/raspi-blinka.py
#  sudo python3 raspi-blinka.py
#  sudo pip3 install adafruit-circuitpython-sht31d
#  

import board
import adafruit_sht31d
import json

i2c = board.I2C()
h = adafruit_sht31d.SHT31D(i2c)

result = {}
try:    
    result["temperature_c"] = h.temperature
    result["humidity"] = h.relative_humidity
    result["temperature_f"] = (result["temperature_c"]*1.8) + 32
    result["error"] = False
except:
    result["temperature_c"] = 0.0
    result["humidity"] = 0.0
    result["temperature_f"] = (result["temperature_c"]*1.8) + 32
    result["error"] = True

print(json.dumps(result))

Any help would be appreciate. Python is not my native language.

[wishmaster270]

@Brown19 Hi,

your python script looks good to me and also the output of node_helper till the moment it tries to send the data to the frontend.
Can you provide your MagicMirror and nodejs version information to me, please?

[wishmaster270]

@Brown19

I tried your script and the current version of the module in both of my setups (2.24.0 native and 2.25.0-develop container) and do not have any problems.

As i wrote already the problem looks like there is problem during communication between the node_helper.js and the frontend (either electron or the browser of your choice).

[Brown19]

@wishmaster270 I’m running 2.24.0 and node is v18.17.0

[wishmaster270]

@Brown19 Do you see any errors in the development console of the browser?

[wishmaster270]

@Brown19
Hi,

today i installed a new instance of MagicMirror 2.24.0 with both your node version 18 any my current used one (16).
In the installation which uses electron i can reproduce the error now. But i am pretty sure this is a problem related to the combination of the version 2.24.0 and the used electron version.
I found this thread with the same error but MMM-Tools instead in the forum of bogusnet, too.
It might be a general MagicMirror issue and not a problem of the module.

Maybe one of the core developers can have a look into it. I never had been that deep in the MagicMirror code and do not have much time to investigate the problem at the moment.

[sdetweil]

@wishmaster270 what module is this? I’ll look at it tonight.

[wishmaster270]

@sdetweil Hi Sam, it looks like both MMM-Temperature and MMM-Tools cause the error.

[wishmaster270]

@sdetweil @Brown19
Hi,

i did some more investigation today and think i found a solution.
Although the exception looks different i think the problem is the execSync command.
The only way i was able to fix it is to use spawnSync.

But i can not say where or why the problem happens.
I tried different node versions (latest 16, 18, 20) and different electron versions (25.3.0, 25.3.2 and 25.4.0) with execSync.

I will release a new version of MMM-Temperature today which uses spawnSync instead of execSync.

[sdetweil]

@wishmaster270 good catch. I think exec is foreground, spawn is background.