ADC Differential Pi Python Library

Python Library to use with ADC Differential Pi Raspberry Pi development board

The example python files can be found in /ABElectronics_Python_Libraries/ADCDifferentialPi/demos

Downloading and Installing the library

Python 3

To install the library you will need the Python3 build and install packages. To install them run the following command.

sudo apt update
sudo apt install python3-build python3-installer git

Download the ABElectronics_Python_Libraries to your Raspberry Pi:

git clone https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git

To install the python library navigate into the ABElectronics_Python_Libraries folder and run:

python3 -m build
sudo python3 -m installer dist/*.whl

Python 2

If you want to install the library on older versions of Linux using Python 2 you can run the following command.

sudo python setup.py install

If you have PIP installed you can install the library directly from GitHub with the following command replacing python2.7 with the version of Python on your computer:

sudo python2.7 -m pip install git+https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git

Using classes without installing the library

To use a specific part of our Python library in your project without installing the entire library, you can simply copy the needed class file into your project's directory. For example, to use the ADC Differential Pi, copy the ADCDifferentialPi.py file from the ADCDifferentialPi directory to where your project files are located. After doing this, you can use the class in your program by adding an import statement at the beginning of your Python code. This allows you to directly utilize the class's functionality in your project.

from ADCDifferentialPi import ADCDifferentialPi

Required Libraries

The library requires smbus2 or python-smbus to be installed

For Python 2.7:

sudo pip install smbus2

For Python 3:

sudo pip3 install smbus2

Classes:

ADCDifferentialPi(address, address2, rate, bus)

Parameters:
address: I2C address for channels 1 to 4, defaults to 0x68
address2: I2C address for channels 5 to 8, defaults to 0x69
rate: bit rate, values can be 12, 14, 16 or 18. Defaults to 18
bus (optional): I2C bus number (integer). If no value is set the class will try to find the i2c bus automatically using the device name.

Functions:

read_voltage(channel) 

Read the voltage from the selected channel
Parameters: channel - 1 to 8 Returns: number as a float between -2.048 and +2.048

read_raw(channel) 

Read the raw int value from the selected channel
Parameters: channel - 1 to 8 Returns: number as an int

set_pga(gain)

Set the gain of the PGA on the chip
Parameters: gain - 1, 2, 4, 8
Returns: null

set_bit_rate(rate)

Set the sample bit rate of the ADC
Parameters: rate - 12, 14, 16, 18
Returns: null
12 = 12 bit (240SPS max)
14 = 14 bit (60SPS max)
16 = 16 bit (15SPS max)
18 = 18 bit (3.75SPS max)

set_conversion_mode(mode)

Set the conversion mode for the ADC
Parameters: mode - 0 = One-shot conversion, 1 = Continuous conversion
Returns: null

Usage

To use the ADC Differential Pi library in your code you must first import the library:

from ADCDifferentialPi import ADCDifferentialPi

Next, you must initialise the ADCDifferentialPi object:

adc = ADCDifferentialPi(0x68, 0x69, 18)

The first two arguments are the I2C addresses of the ADC chips. The values shown are the default addresses of the ADC board.

The third argument is the sample bit rate you want to use on the ADC chips. The sample rate can be 12, 14, 16 or 18

You can now read the voltage from channel 1 with:

adc.read_voltage(1)