ADC DAC Pi Python Library

Python Library to use with ADC DAC Pi Zero Raspberry Pi development board.

The example python files can be found in /ABElectronics_Python_Libraries/ADCDACPi/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 DAC Pi, copy the ADCDACPi.py file from the ADCDACPi 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 ADCDACPi import ADCDACPi

Required Libraries

The library requires spidev to be installed

View our knowledgebase article SPI and Python on Raspberry Pi OS for installation instructions.

Functions:

Initialising the ADCDACPi object.

adcdac = ADCDACPi(gain_factor)

Parameter: gain_factor - 1 or 2 When the gain is set to 1 the voltage range of the DAC will be 0 to 2.048V. When the gain is set to 2 the voltage will be 0 to 3.3V

read_adc_voltage(channel, mode) 

Read the voltage from the selected channel on the ADC
Parameter: channel - 1 or 2
Parameter: mode - 0 = single-ended, 1 = differential
Returns: number as a float between 0 and 2.048

read_adc_raw(channel, mode) 

Read the raw value from the selected channel on the ADC
Parameter: channel - 1 or 2
Parameter: mode - 0 = single-ended, 1 = differential
Returns: int

set_adc_refvoltage(voltage)

Set the reference voltage for the analogue to digital converter.
The ADC uses the raspberry pi 3.3V power as a voltage reference so using this method to set the reference to match the exact output voltage from the 3.3V regulator will increase the accuracy of the ADC readings.
Parameters: voltage
Returns: null

set_dac_voltage(channel, voltage)

Set the voltage for the selected channel on the DAC. The DAC has two gain values, 1 or 2, which can be set when the ADCDACPi object is created. A gain of 1 will give a voltage between 0 and 2.047 volts. A gain of 2 will give a voltage between 0 and 3.3 volts.
Parameters: channel - 1 or 2, voltage - target DAC voltage
Returns: null

set_dac_raw(channel, value)

Set the raw value for the selected channel on the DAC
Parameters: channel - 1 or 2, value int between 0 and 4095
Returns: null

Usage

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

from ADCDACPi import ADCDACPi

Next you must initialise the ADCDACPi object and set a gain of 1 or 2 for the DAC:

adcdac = ADCDACPi(1)

Set the reference voltage.

adcdac.set_adc_refvoltage(3.3)

Read the voltage from channel 2 and display it on the screen

print adcdac.read_adc_voltage(2)