ADC Differential Pi Node JS Library

Node JS Library to use with ADC Differential Pi Raspberry Pi development.

Install

To download to your Raspberry Pi type in the terminal:

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

The ADC Differential Pi library is located in the /lib/adcdifferentialpi/ directory

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

The ADC Differential Pi library requires the i2c-bus library to run.

Install from npm package repository with

npm install i2c-bus

Functions:

readVoltage(channel) 

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

readRaw(channel) 

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

setPGA(gain)

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

setBitRate(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)

setConversionMode(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:

var adcpi = require('../../lib/adcpi/adcpi');

Next, you must initialise the adc object and smbus:

var adc = new ADCPi(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.readVoltage(1);