Description

The ADS1115 is an ultra-compact, high-precision 16-bit Analog-to-Digital Converter (ADC) module. While many microcontrollers (like standard Arduinos) only feature a basic 10-bit or 12-bit internal ADC, or lack analog inputs entirely (like the Raspberry Pi or ESP8266), this module provides a massive upgrade—allowing you to read precise, high-resolution analog signals over a simple I2C interface.

If you need to read highly sensitive analog sensors with absolute precision, the ADS1115 module is the ideal choice. It features 4 independent analog input channels that can be configured as 4 single-ended inputs or 2 differential inputs (perfect for measuring the difference between two signals or reading negative voltages).

Noise Performance

Delta-sigma (ΔΣ) analog-to-digital converters (ADCs) are based on the principle of oversampling. The input signal of a ΔΣ ADC is sampled at a high frequency (modulator frequency) and subsequently filtered and decimated in the digital domain to yield a conversion result at the respective output data rate. The ratio between modulator frequency and output data rate is called oversampling ratio (OSR). By increasing the OSR, and thus reducing the output data rate, the noise performance of the ADC can be optimized. In other words, the input-referred noise drops when reducing the output data rate because more samples of the internal modulator are averaged to yield one conversion result. Increasing the gain also reduces the input-referred noise, which is particularly useful when measuring low-level signals.

Key Features:

• 16-Bit High Resolution: Provides 65,536 discrete voltage levels, allowing you to detect miniscule changes in voltage that standard microcontrollers miss.
• Programmable Gain Amplifier (PGA): Features a built-in amplifier that can boost tiny analog signals (up to x16) so you can measure small voltages (like millivolts) with full resolution.
• 4-Channel Flexibility: Easily switches between 4 single-ended channels or 2 differential pairs depending on your project requirements.
• Adjustable I2C Address: Features an address pin (ADDR) that allows up to 4 ADS1115 modules to be connected to the same I2C bus simultaneously, giving you up to 16 analog inputs.
• Wide Compatibility: Essential add-on for Raspberry Pi, ESP8266, ESP32, and Arduino projects requiring high-precision analog sensing.

Technical Specifications:

Pinout Configuration:

• VDD: Power Input (2.0V – 5.5V)
• GND: Ground
• SCL: I2C Serial Clock
• SDA: I2C Serial Data
• ADDR: I2C Address Pin (Tie to GND, VDD, SDA, or SCL to change address)
• ALRT: Alert/Interrupt Output (Triggers when conversion is ready)
• A0 – A3: Analog Input Channels 0, 1, 2, and 3

Common Applications:

• Battery Voltage Monitoring: Precision monitoring of lithium-ion or multi-cell battery packs.
• Sensor Interfacing: Reading low-voltage outputs from load cells (weighing scales), gas sensors, thermocouples, and light sensors.
• Raspberry Pi Projects: Adding reliable analog input capability to any Raspberry Pi board.
• Industrial Process Control: Monitoring precise current loops and analog transducer signals.