Wiki: Ads 1015 Analog Digital Converter

ADS1015 Analog-Digital Converters (click to enlarge)

The ADS1015 is a Texas Instruments +/-24V Analog Digital Converter implemented by both AdaFruit and Pimoroni (the latter as a Breakout Garden board), both I2C compatible boards. It can be used to measure an analog voltage between -24V DC to +24V DC, returning a value with 12 bit precision.

The ADS1015 has four channels (labeled A0, A1, A2 and A3) that can read voltages from -24V to +24V at sampling rates up to 3.3KHz with a 12-bit resolution. The Pimoroni board only provides three of these channels as usable pins.

The thumbnail image to the right is roughly the size of the boards, which measures 24 x 21mm. As of January 2020 the price of the AdaFruit board is US$9 (~NZ$14), the price of the Pimoroni board is £12 (~NZ$24).

Features#

ADS1015 Block Diagram

12-bit precision
+/- 24V (DC) measurement range
three or four channels (the TI ADS1015 has four: AdaFruit's provides all four, whereas Pimoroni's board only provides connections to three of them)
programmable gain (please consult the ADS1015 TI datasheet for details; the default is set at ±2.048V)
pp to 3.3KHz sampling rate
I2C interface (address 0x48/0x49 (cut trace))
3.3V or 5V compatible
reverse polarity protection
compatible with all models of Raspberry Pi, and Arduino
ads1015-python library on github

Installation#

You'll need Python and pip (or pip3 for Python 3) already installed.

If you're using Python 2, just run:

sudo pip install ads1015

For Python 3, use:

sudo pip3 install ads1015

Example Usage#

The board has three input pins, labeled A0, A1 and A2. Plugging a signal into A0, here's an example of some code to repeatedly read the voltage on the pin until you type Ctrl-C:

    #!/usr/bin/env python3
    import time      
    from ads1015 import ADS1015
    
    print('''read-all.py - read the A0 input of the ADC.
    
    Press Ctrl+C to exit!
    ''')
     
    CHANNEL = 'in0/ref'
    ads1015 = ADS1015()
    ads1015.set_mode('single')
    ads1015.set_programmable_gain(2.048)
    ads1015.set_sample_rate(1600)
     
    reference = ads1015.get_reference_voltage()
    print("Reference voltage: {:6.3f}v \n".format(reference))
    
    try:
        while True:
            value = ads1015.get_compensated_voltage(channel=CHANNEL, reference_voltage=reference)
            print("A0 value: {:6.3f}v".format(value))
            time.sleep(0.5)
    
    except KeyboardInterrupt:
        pass

References#

ADS1015 12-Bit ADC - 4 Channel with Programmable Gain Amplifier Adafruit product page
ADS1015 +/-24V ADC breakout Pimoroni product page
ADS101x Ultra-Small, Low-Power, I2C-Compatible, 3.3-kSPS, 12-Bit ADCs With Internal Reference, Oscillator, and Programmable Comparator datasheet from Texas Instruments

Tags: Sensor