For microcontrollers without an analog-to-digital converter or when you want a higher-precision ADC, the ADS1015 provides 12-bit precision at 3300 samples/second over I2C. The chip can be configured as 4 single-ended input channels, or two differential channels.
As a nice bonus, it even includes a programmable gain amplifier, up to x16, to help boost up smaller single/differential signals to the full range.
We like this ADC because it can run from 2V to 5V power/logic, can measure a large range of signals and its super easy to use.
The chip's fairly small so it comes on a breakout board with ferrites to keep the AVDD and AGND quiet.
Interfacing is done via I2C. The address can be changed to one of four options so you can have up to 4 ADS1015's connected on a single 2-wire I2C bus for 16 single ended inputs.
To get you started, we have example code for both the Raspberry Pi (in our Adafruit Pi Python library) and Arduino (in our ADS1X15 Arduino library repository) Simply connect GND to ground, VDD to your logic power supply, and SCL/SDA to your microcontroller's I2C port and run the example code to start reading data.
WIDE SUPPLY RANGE: 2.0V to 5.5V
LOW CURRENT CONSUMPTION: Continuous Mode: Only 150µA Single-Shot Mode: Auto Shut-Down
PROGRAMMABLE DATA RATE: 128SPS to 3.3kSPS
INTERNAL LOW-DRIFT VOLTAGE REFERENCE
I2C INTERFACE: Pin-Selectable Addresses
FOUR SINGLE-ENDED OR TWO DIFFERENTIAL INPUTS
This board/chip uses I2C 7-bit addresses between 0x48-0x4B, selectable with jumpers
Datasheets, Fritzing object, and EagleCAD PCB files available in the product tutorial