/dmm-ble-mp730026

Python code to access the a Multicomp Pro MP730026 DMM over BLE

Primary LanguageJavaScriptMIT LicenseMIT

dmm-ble-mp730026

[TOC]

About

Python code to access the a Multicomp Pro MP730026 (and others) DMM over BLE

This multimeter supports communication over Bluetooth, however, the official software is not very good. It only works with a specific dongle.

Using the bleak python module, virtually any operation system and Bluetooth controller works. So far I have successfully used this code with:

  • Linux: Raspberry Pi 3B, Raspberry Pi 4, Raspberry Pi0W *Recommended

  • macOS: Macbook Pro and MacPro (Trashcan)

  • Windows 10: Microsoft Surface Book Pro 2

The intent for the code is to provide an object representing the DMM.

bleak_scan.py can be used to find the MAC address of your meter.

Installation

The recommended method for installing is to use git on a Raspberry Pi

git clone https://github.com/baldengineer/dmm-ble-mp730026.git

setup on Raspberry Pi:

cd ~/dmm-ble-mp730026
./pi_setup.sh

setup on Windows:

WIP

This will install the appropriate programs needed and create a python virtual environment

Note about dmm.js

Building dmm.js requires installing node and some node modules to build it from source. These will install locally inside the scripts folder. The installation script will then build dmm.js.

Before first run

Copy the settings.py.template to settings.py This file will not be over-written on updates.

The multi_meters is a comma separated list for each meter you wish to connect to. The template currently has MP730026 as meter 0, and Demo as meter 1.

See Supported Meters for specific configurations to pass.

Running

On Raspberry Pi, use:

cd ~/dmm-ble-mp730026
./run.sh

Will start up the webserver, websocket server and Bluetooth services for getting data from the meter.

If you get a permissions error on Raspberry Pi see Raspberry Pi Permissions

Advanced Usage

This library exposes a DMM object that exposes all the data for a mp730026 multimeter

  self.address = address   # Devices MAC address
  self.mode = False        # Current measurement Mode. EG AC voltage
  self.hold = False        # hold Flag
  self.rel = False         # rel Flag
  self.value = False       # String containing 4 digit and one decimal Value
  self.suffix = False      # String of data suffix. EG mV KΩ
  self.decimal = False     # Decimal Position
  self.negative = False    # If the number is a negative value
  self.autorange = False   # Auto-range flag
  self.connected = False   # Returns the status of the meter
  self.digits = 4          # The number of digits the meter can display
  self.model = "Mfg Model" # Manufacturer and Model numbers of meter

These values are updated by calling parse() with a raw byte array of the data from the DMM.

DMM.parse([0x23, 0xF0, 0x04, 0x00, 0xDE, 0x85])

# this fills the object variables as such
mode = "DC volts"
hold = False
rel = False
value = -1.502
suffix = "V"
decimal = 1
negative = False
autorange = False

Accessing the Data

You can access the web front end on port 18881, example: http://192.168.1.71:18881

Shortcut for meter 0 you can use http://192.168.1.71:18881/0 Shortcut for meter 1 you can use http://192.168.1.71:18881/1 etc...

These will redirect you to a longer URL that has settings for colors and label text that you can tweak with the information in Example URLs

Example URLs

Included is an example for connecting a meter to a web-socket for sending the data across the internet, In this case to a web page to show off the multimeter reading in real time.

Accessing Live Data

Opening meter.html either locally or hosted with the following flags

*websocketserver required

IP Address or Host name of server, eg 127.0.0.1, 192,168.1.100, raspberrypi

websocketport

Web socket port, defaults to 18881

meter

Give an integer value that matches the index in your settings.py. For the first meter use 0, second, 1, etc...

Defaults to meter 0 if no value is passed, or is an invalid value.

background

RGB syntax or HTML color names,

rgb(250,128,114)
salmon

oncolor

Color of the darker background elements of the display

offcolor

Color of the brighter foreground elements

Examples

Accessing Saved Data

Open saved.html either locally or hosted with the same flags as Accessing Live Data.

Examples

OBS Browser Source

This was actually designed to be used with OBS as a browser source. The URL you generated above goes in URL height and width are as follows

width = 250
height = 85

All other defaults are fine.

Raspberry Pi Permissions

Permissions for the Pi user to access Bluetooth are needed

sudo adduser pi bluetooth

Also you will need to modify a file according to this post

Windows - Failed Building Wheel

If you get a Failed Building Wheel error or txdbus ModuleNotFound error you need to install the Twisted wheel manually.

Download the appropriate version from https://www.lfd.uci.edu/~gohlke/pythonlibs/#twisted

If you are using python 3.8, windows 64 bit download Twisted-20.3.0-cp38-cp38-win_amd64.whl

Then install with

source .venv/Scripts/activate
pip install %userprofile%\Downloads\Twisted-20.3.0-cp38-cp38-win_amd64.whl

Then run pip install -r requirements.txt again.

Hosting

The html interface can be locally provided to a web browser or OBS source. However if one desires to host it remotely a nginx file has been provided.

Install Nginx and link file

sudo apt-get install nginx
sudo rm /etc/nginx/sites-available/default # Warning: This will remove the default nginx page
ln ~/dmm-ble-mp730026/nginx-site /etc/nginx/sites-available/default

Supported Meters

Mfg Model Required Parameters Optional Parameters Settings.py Example
Multicomp MP730026 MAC_Address MP730026("AA:AA:AA:AA:AA:AA")
Owon OW18B MAC_Address OW18B("AA:AA:AA:AA:AA:AA")
Demo Name Demo(), Demo("My Demo")

Support for more meters is in progress. If you have a meter you would like to be supported, please check the Issues, and add a new Issue if no one else has requested it.

Demo