ADS1X15 - Analog to Digital Converter

The ADS1015 and ADS1115 are analog voltage sensors using the I2C-protocol for communication.

Library

To use the ADS1x15, import the library ads1x15

import ads1x15

Function Reference

Open Device

Open()
Open(interface)
Open(interface, address)
Open(interface, address, version)

Open the ADS1X15 on interface interface with I2C address address and device type version.

• interface
  • String
  • Path to I2C-Interface.
  • Optional: default value is "/dev/i2c-1"
• address
  • Integer: 0 … 255
  • Device address
  • Optional: default value is 0x48
• version
  • Integer: 0 or 1
  • ADS1115 -> version = 1
  • ADS1015 -> version = 0
  • Optional: default value is 1

Example:

Open("/dev/i2c-1", 0x48, 1)

Set Channel

Channel(n)

Set channel for measurement.

• n

  • Integer: 0 … 7

    n	Type	Pin
    0	differential	A0 - A1
    1	differential	A0 - A3
    2	differential	A1 - A3
    3	differential	A2 - A3
    4	single-ended	A0
    5	single-ended	A1
    6	single-ended	A2
    7	single-ended	A3

Set Voltage Range

VoltageRange()
VoltageRange(V)

Set the voltage range in Volts. Any value less than the minimum value will set the minimum voltage range. Any value greater than the maximum value will set the maximum voltage range. The first voltage range greater than or equal the the specified value will be set.

• V
  • Float: 0.256, 0.512, 1.024, 2.048, 4.096 or 6.144

Example:

VoltageRange(1024)  ' Set voltage range to 1.024V
VoltageRange(1025)  ' Set voltage range to 2.048V

Set Sample Rate

SampleRate()
SampleRate(S)

Set the sample rate in samples/second. Any value less than the minimum value will set the minimum sample range. Any value greater than the maximum value will set the maximum sample range. The first sample range greater than or equal the the specified value will be set.

• S
  • Integer
    • ADS1015: 128, 250, 490, 1600, 2400, 3300
    • ADS1115: 8, 16, 32, 64, 128, 250, 475, 860
    • Optional: default value is 128

Example:

SampleRate(128)

Read Voltage

V = Read()

Measure the voltage.

• V
  • Float
  • Measured voltage in Volts

Set continious mode

ContiniousMode()

Set ADS1X15 to continious measurement mode. ADS1x15 will measure with the specified sample rate. The read-command will return the value of the last measurement.

Set single shot mode

SingleShotMode()

Set ADS1x15 to single shot mode. Each read-command will initiate a measurement.

Close device

Close()

Close the ADS1X15 device.

Example

For running this example, you need an ADS1015 or ADS1115 sensor. SmallBASIC PiGPIO 2 is using the I2C-protocol for communication. The Raspberry Pi supports this protocol in hardware, but by default the protocol is disabled. Therefore you have to setup I2C as described here.

In the next step please wire the sensor as shown in the following image. The example is using an ADS1115 but the ADS1015 will work, too. Use a 10K potentiometer.

The I2C bus is using pin 2 (SDA1) and 3 (SCL1). The sensor can be driven with a voltage from 2.2 to 5.5V. The input pins can be connected to -0.3V to VDD + 0.3V. If you drive the sensor with 5V from the Pi, the maximum allowed voltage at the input pins is 5.3V. If you drive the sensor with 3.3V, the maximum allowed voltage at the input pins is 3.6V.

import ads1x15 as adc

const A0  = 4   ' Input A0
const A1  = 5   ' Input A1
const A2  = 6   ' Input A2
const A3  = 7   ' Input A3
const A01 = 0   ' Differential Input A0 - A1
const A03 = 1   ' Differential Input A0 - A3
const A13 = 2   ' Differential Input A1 - A3
const A23 = 3   ' Differential Input A2 - A3


adc.Open("/dev/i2c-1", 0x48)    ' Open device
adc.Channel(A0)                 ' Set input channel A0
adc.VoltageRange(6.144)         ' Set Voltage range from 0 to 6.144V
adc.SampleRate(128)             ' 128 Samples per second


for ii = 1 to 10
    delay(500)
    print adc.Read()            ' Returns voltage as float
next

adc.Close()                     ' Close connection