Python woes

[SteamyTea]

I don't know if we have any Python/RPi experts here, but I am struggling to get an i²c infrared thermometer to work.

The sensor is a cheap CJMCU one, which is an mlx90614, sometimes also known as a GY-906.

I have installed all the relevant libraries i.e. adafruite_mlx90614, smbus2, etc, but may have missed something key.

 

I can get it connected and showing up with i2cdetect -y 1 as 5b and plays nicely with my RTC (which may or may not be UU)

 

When I run the below test python programme it returns [0, 91], which I have no idea what it means but seems to show it is connected and can be locked out

import busio
from board import *

i2c = busio.I2C(SCL, SDA)
i2c.try_lock()
print(i2c.scan())
i2c.unlock()
i2c.deinit()

When I come to run the proper Python programme I get this message.

 

from smbus2 import SMBus
from adafruite_mlx90614 import MLX90614

bus = SMBus(1)
sensor = MLX90614(bus, address=0x5b)
print (sensor.get_amb_temp())
print (sensor.get_obj_temp())
bus.close()

 

I then played about and wrote this, but get this message

 

from smbus2 import SMBus, i2c_msg
from adafruit_mlx90614 import MLX90614

with SMBus(1) as bus:
        with MLX90614 as sensor:
                bus = SMBus()
                sensor1 = sensor(bus, address=0x5b)

                print(sensor1.get_ambient())
 

 

 

A bit more playing and I get this message.

 

from smbus2 import SMBus
from adafruit_mlx90614 import MLX90614

TemperatureModule._sensor = MLX90614(1, 0x5B)
while not i2c.try_lock():

        temperature = TemperatureModule._sensor.get_object_1()
        temperature1 = TemperatureModule._sensor.get_ambient()
 

And after staying up to gone 9PM last night, and a few hours this morning, I am completely at a loss.

I have spent literally hours searching this and there seems to be very little information PyPi does suggest a command is tried first, but it made not difference.

 

Can anyone help?

(when I say help, I mean actually write it for me)

 

Edited January 19, 2024 by SteamyTea

[S2D2]

adafruit_mlx90614 is the CircuitPython library (https://docs.circuitpython.org/projects/mlx90614/en/latest/api.html) so you'd have to flash the firmware to your microcontroller. I'm assuming instead you're using a zero or such with a standard python install, so you'd want another library. The one you linked might work but note the different name for pip/include: https://pypi.org/project/PyMLX90614/

 

Full disclaimer I've never used any of this stuff so could be completely wrong.

[SteamyTea]

1 minute ago, S2D2 said:

I'm assuming instead you're using a zero

Yes, a Pi Zero W

 

I think I have an old proper board or 3, may give it a go on that.

 

Thanks for your help, lets see what happens.

[S2D2]

1 minute ago, SteamyTea said:

Yes, a Pi Zero W

 

I think I have an old proper board or 3, may give it a go on that.

 

Thanks for your help, lets see what happens.

Zero and 3 will behave the same (full OS with Python on top). CircuitPython is for things like the Pico.

 

Good luck.

[SteamyTea]

8 minutes ago, S2D2 said:

CircuitPython is for things like the Pico.

That could account for it then.

I have booted up one of my old Pis and shall see if I can get the proper libraries on it.

 

Thanks again, most days are school days.

(just spent over a day looking for my old car V5 document, found some "O" level certificates, they are well over 40 years old, and my Birth Certificate, which is even older.  I did find the V5, right where I left it.)

[TerryE]

Nick, have a look at the Datasheet for the MLX90614.  It runs a proprietary 2-wire protocol that isn't quite I2C. This might confuse the RPi I2C driver, but the easiest is to have a look at the various MLX90614 on RPi YouTube videos, e.g. 

 

 

Edited January 26, 2024 by TerryE