loadstar-sensors-interface 2.1.1

Python async interface to Loadstar Sensors USB devices.

• About

• Example Usage

• Installation

• Development

About

- Python Package Name: loadstar_sensors_interface
- Description: Python async interface to Loadstar Sensors USB devices.
- Version: 2.1.1
- Python Version: 3.9
- Release Date: 2023-02-09
- Creation Date: 2022-08-16
- License: BSD-3-Clause
- URL: https://github.com/janelia-pypi/loadstar_sensors_interface_python
- Author: Peter Polidoro
- Email: [e-mail]
- Copyright: 2023 Howard Hughes Medical Institute
- References:
  - https://pyserial-asyncio.readthedocs.io/en/latest/
  - https://python.readthedocs.io/en/latest/library/asyncio.html
  - https://pint.readthedocs.io/en/stable/getting/overview.html
  - https://tinkering.xyz/async-serial/
  - https://www.loadstarsensors.com/
  - https://www.loadstarsensors.com/di-100u-di-1000u-command-set.html
- Dependencies:
  - pyserial-asyncio
  - pint
  - click

Example Usage

Python

from loadstar_sensors_interface import LoadstarSensorsInterface
import asyncio

async def my_sensor_value_callback(sensor_value):
    print(f'sensor value magnitude: {sensor_value.magnitude}, units: {sensor_value.units}')
    await asyncio.sleep(0)

async def example():
    dev = LoadstarSensorsInterface()
    await dev.open_high_speed_serial_connection(port='/dev/ttyUSB0')
    dev.set_sensor_value_units('gram')
    dev.set_units_format('.1f')
    await dev.tare()
    dev.start_getting_sensor_values(my_sensor_value_callback)
    await asyncio.sleep(5)
    await dev.stop_getting_sensor_values()
    count = dev.get_sensor_value_count()
    duration = dev.get_sensor_value_duration()
    rate = dev.get_sensor_value_rate()
    print(f'{count} sensor values in {duration} at a rate of {rate}')
    await dev.print_device_info()

asyncio.run(example())

Command Line

help

loadstar --help
# Usage: loadstar [OPTIONS]

#   Command line interface for loadstar sensors.

# Options:
#   -p, --port TEXT          Device name (e.g. /dev/ttyUSB0 on GNU/Linux or COM3
#                            on Windows)
#   -H, --high-speed         Open serial port with high speed baudrate.
#   --debug                  Print debugging information.
#   -i, --info               Print the device info and exit
#   -T, --tare               Tare before getting sensor values.
#   -d, --duration INTEGER   Duration of sensor value measurements in seconds.
#                            [default: 10]
#   -u, --units TEXT         Sensor value units.  [default: gram]
#   -f, --units-format TEXT  Units format.  [default: .1f]
#   -h, --help               Show this message and exit.

device info

# DI-100, DI-1000
loadstar --port /dev/ttyUSB0 --info

# DI-1000UHS
loadstar --port /dev/ttyUSB0 --high-speed --info
# device info:
# port                     /dev/ttyUSB0
# baudrate                 230400
# model                    FCM DI-1000
# id                       F230235995
# sensor_value_units       gram
# units_format             .1f
# load_capacity            2041.2 gram

example usage

# DI-100, DI-1000
loadstar --port /dev/ttyUSB0 --tare --duration 10 --units kilogram --units-format=.3f

# DI-1000UHS
loadstar --port /dev/ttyUSB0 --high-speed --tare --duration 10 --units kilogram --units-format=.3f
# 2023-02-03 18:35:11.086982 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.087548 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.088130 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.088705 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.089174 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.089540 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.089905 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.090268 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.090634 - sensor_value -> 0.500 kilogram
# 2023-02-03 18:35:11.091001 - sensor_value -> 0.500 kilogram
# 5166 sensor values in 10.051 second at a rate of 513.980 hertz
# device info:
# port                     /dev/ttyUSB0
# baudrate                 230400
# model                    FCM DI-1000
# id                       F230235995
# sensor_value_units       kilogram
# units_format             .3f
# load_capacity            2.041 kilogram

Installation

https://github.com/janelia-pypi/python_setup

GNU/Linux

Drivers

GNU/Linux computers usually have all of the necessary drivers already installed, but users need the appropriate permissions to open the device and communicate with it.

Udev is the GNU/Linux subsystem that detects when things are plugged into your computer.

Udev may be used to detect when a loadstar sensor is plugged into the computer and automatically give permission to open that device.

If you plug a sensor into your computer and attempt to open it and get an error such as: "FATAL: cannot open /dev/ttyUSB0: Permission denied", then you need to install udev rules to give permission to open that device.

Udev rules may be downloaded as a file and placed in the appropriate directory using these instructions:

99-platformio-udev.rules

1. Download rules into the correct directory

   curl -fsSL https://raw.githubusercontent.com/platformio/platformio-core/master/scripts/99-platformio-udev.rules | sudo tee /etc/udev/rules.d/99-platformio-udev.rules
   

2. Restart udev management tool

   sudo service udev restart
   

3. Ubuntu/Debian users may need to add own “username” to the “dialout” group

   sudo usermod -a -G dialout $USER
   sudo usermod -a -G plugdev $USER
   

4. After setting up rules and groups

   You will need to log out and log back in again (or reboot) for the user group changes to take effect.

   After this file is installed, physically unplug and reconnect your board.

Python Code

The Python code in this library may be installed in any number of ways, chose one.

1. pip

   python3 -m venv ~/venvs/loadstar_sensors_interface
   source ~/venvs/loadstar_sensors_interface/bin/activate
   pip install loadstar_sensors_interface
   

2. guix

   Setup guix-janelia channel:

   https://github.com/guix-janelia/guix-janelia

   guix install python-loadstar-sensors-interface
   

Windows

Drivers

Download and install Windows driver:

Loadstar Sensors Windows Driver

Python Code

The Python code in this library may be installed in any number of ways, chose one.

1. pip

   python3 -m venv C:\venvs\loadstar_sensors_interface
   C:\venvs\loadstar_sensors_interface\Scripts\activate
   pip install loadstar_sensors_interface
   

Development

Clone Repository

git clone [e-mail]:janelia-pypi/loadstar_sensors_interface_python.git
cd loadstar_sensors_interface_python

Guix

Install Guix

Install Guix

Edit metadata.org

make -f .metadata/Makefile metadata-edits

Tangle metadata.org

make -f .metadata/Makefile metadata

Develop Python package

make -f .metadata/Makefile guix-dev-container
exit

Test Python package using ipython shell

make -f .metadata/Makefile guix-dev-container-ipython
import loadstar_sensors_interface
exit

Test Python package installation

make -f .metadata/Makefile guix-container
exit

Upload Python package to pypi

make -f .metadata/Makefile upload

Test direct device interaction using serial terminal

1. Low Speed

   DI-100, DI-1000

   make -f .metadata/Makefile guix-dev-container-port-serial # PORT=/dev/ttyUSB0
   # make -f .metadata/Makefile PORT=/dev/ttyUSB1 guix-dev-container-port-serial
   ? # help
   settings
   [C-a][C-x] # to exit
   

2. High Speed

   DI-1000UHS

   make -f .metadata/Makefile guix-dev-container-port-serial-hs # PORT=/dev/ttyUSB0
   # make -f .metadata/Makefile PORT=/dev/ttyUSB1 guix-dev-container-port-serial-hs
   ? # help
   settings
   [C-a][C-x] # to exit
   

Test Python package using ipython shell with serial port access

make -f .metadata/Makefile guix-dev-container-port-ipython # PORT=/dev/ttyUSB0
# make -f .metadata/Makefile PORT=/dev/ttyUSB1 guix-dev-container-port-ipython
import loadstar_sensors_interface
exit

Test Python package installation with serial port access

make -f .metadata/Makefile guix-container-port # PORT=/dev/ttyUSB0
# make -f .metadata/Makefile PORT=/dev/ttyUSB1 guix-container-port
exit

Docker

Install Docker Engine

https://docs.docker.com/engine/

Develop Python package

make -f .metadata/Makefile docker-dev-container
exit

Test Python package using ipython shell

make -f .metadata/Makefile docker-dev-container-ipython
import loadstar_sensors_interface
exit

Test Python package installation

make -f .metadata/Makefile docker-container
exit

Test Python package using ipython shell with serial port access

make -f .metadata/Makefile docker-dev-container-port-ipython # PORT=/dev/ttyUSB0
# make -f .metadata/Makefile PORT=/dev/ttyUSB1 docker-dev-container-port-ipython
import loadstar_sensors_interface
exit

Test Python package installation with serial port access

make -f .metadata/Makefile docker-container-port # PORT=/dev/ttyUSB0
# make -f .metadata/Makefile PORT=/dev/ttyUSB1 docker-container-port
exit