Grove 4 Channel 16 Bit ADC Board based on ADS1115

No question about it. The lack of an Analog to Digital Converter is a pain on the Raspberry Pi. We want to read those real world signals all the time and we didn't have a good way of doing it. And not one really workable ADC for the Grove either. So, we designed the board above. 4 channels of 16 bit Analog to Digital nirvana. Based on the TI ADS1115 IC. Connects to a Grove I2C connector and supplies 4 channels of Grove Analog plugs for your projects.

Learn what Grove Connecters are here in our tutorial.

Features

• The Missing Board for the Raspberry Pi
• 4 Channels with Grove Connectors
• Grove I2C connector provided
• Headers provided for non Grove usage
• Supports both 3.3V and 5V I2C
• Open Source Drivers Provided for Raspberry Pi/Arduino/ESP8266

Downloads

Current Specification for Grove4Ch16BitADC Board Raspberry Pi Pure Python Software is at: https://github.com/switchdoclabs/SDL_Pi_Grove4Ch16BitADC Arduino and ESP8266 Software is at: https://github.com/switchdoclabs/SDL_Arduino_Grove4Ch16BitADC

Theory of Operation

The ADS1115 is a very small, low-power, 16-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC). The ADS111/5 are extremely easy to configure and design into a wide variety of applications, and allow precise measurements to be obtained with very little effort. Both experienced and novice users of data converters find designing with the ADS1115 to be intuitive and problem-free. The ADS111/5 consists of a ΔΣ analog-to-digital (A/D) core with adjustable gain, an internal voltage reference, a clock oscillator, and an I2C interface. An additional feature available on the ADS1115 is a programmable digital comparator that provides an alert on a dedicated pin. All of these features are intended to reduce required external circuitry and improve performance. The ADS1115 functional block diagram is shown above. The ADS1115 A/D core measures a differential signal, VIN, that is the difference of AINP and AINN. A MUX is available on the ADS1115. This architecture results in a very strong attenuation in any common-mode signals. The converter core consists of a differential, switched-capacitor ΔΣ modulator followed by a digital filter. Input signals are compared to the internal voltage reference. The digital filter receives a high-speed bitstream from the modulator and outputs a code proportional to the input voltage. The ADS1115 has two available conversion modes: single-shot mode and continuous conversion mode. In single-shot mode, the ADC performs one conversion of the input signal upon request and stores the value to an internal result register. The device then enters a low-power shutdown mode. This mode is intended to provide significant power savings in systems that only require periodic conversions or when there are long idle periods between conversions. In continuous conversion mode, the ADC automatically begins a conversion of the input signal as soon as the previous conversion is completed. The rate of continuous conversion is equal to the programmed data rate. Data can be read at any time and always reflect the most recent completed conversion.