ADC DAC Pi Node JS Library

Node JS Library to use with ADC DAC Pi Raspberry Pi development boards.

Install

To download to your Raspberry Pi type in the terminal:

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

The ADCDAC Pi library is located in the /lib/adcdacpi/ directory

The example files are located in the /examples/adcdacpi/ directory

The ADC DAC Pi library requires the rpio library to run.

Install rpio from npm package repository with

npm install rpio

Functions:

readADCVoltage(channel, mode) 

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

readADCRaw(channel, mode) 

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

setADCRefVoltage(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 - float between 0.0 and 7.0
Returns: null

setDACVoltage(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 ADCDAC 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, the voltage can be between 0 and 2.047 volts
Returns: null

setDACRaw(channel, value)

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

setDACGain(gain)

Set the gain for the DAC. This is used to set the output based on the reference voltage of 2.048V.
When the gain is set to 2 the maximum voltage will be approximately 3.3V.
Parameters: gain - 1 or 2
Returns: null

Usage

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

var adcdac = require('../../lib/adcdacpi/adcdacpi');

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

var adc = new ADCDAC();

Set the reference voltage.

adc.setADCRefVoltage(3.3);

Read the voltage from channel 1 and display it on the screen

console.log('Reading 1 Voltage: ' + adc.readADCVoltage(1, 0));