Hardware: Hive Interface Board 4

Summary

Can operate with the Pi or as a standalone Bluetooth Low Energy (BLE) device. Replaces the HX711 single channel ADC with an 8 channel.

Features

• AD7124 24 bit ADC with 8 differential inputs
• Instrumentation Amplifiers for load cells
• Bluetooth Low Energy (BLE) support using a Nordic nRF52
• BMD301 32 bit ARM processor with GPIO lines and eight 16 bit ADC inputs
• 40 pin header plug into a Pi
• two coin cells to power the BMD301

• BMD301 (Nordic nRF52) can be programmed via the Pi.

Data Sheets

AD7124-8 (pdf)

Design Tools

http://www.analog.com/en/design-center/design-tools-and-calculators/converter-tools.html

Delta Sigma Theory

Delta-sigma ADC basics: Understanding the delta-sigma modulator https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2015/01/21/delta-sigma-adc-basics-understanding-the-delta-sigma-modulator

Delta-sigma ADC digital filter types https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2016/05/13/delta-sigma-adc-digital-filter-types

Delta-sigma ADC digital filter types: sinc filters https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2016/06/10/delta-sigma-adc-digital-filter-types-sinc-filters