Open SDI12-Blue

An open implementation for a SDI-12 Sensor node, based on Ultra-Low-Power Bluetooth CPU

Features

• Build your own SDI-12 V1.3 compatible Ultra-Low-Power Sensor with (often) less than 50 lines of Code
• Use traditional SDI-12 Bus or SDI12-Over-BLE to communicate with your Sensor
• No APP required, use Standard WEB-Blueooth-API (Live demo: BLE API Live (in Repository LTX BLE Demo)
• Optional: Secure Firmware-Updates-over-BLE (via BLE-API), Access Control via PIN, ...
• For humanitary, private or non-commercial use, this project is free!
• ...

*** This is Work In Pogress. If something fails (e.g. casued by changes *** in the software), please read the comments in the sources. *** All sensors have been (basically) tested and SDI-12 V1.3 communication verified

Current State:

• Testsensor (Device Type 200): stable and tested
• Ceramic Pressure Sensor KKD18 (Device Type 300): stable and tested
• Piezo Pressure Sensor KELLER LD (Device Type 310): stable and tested
• Barometric Pressure Sensor MS5607 (Device Type 320): stable and tested
• Frequency and Event Counter (up to 1kHz) (Device Type 330): stable and tested
• Temperature/Humidity Sensors SHT21 (Device Type 340): stable and tested
• High-Precision 24-Bit A/D ADS1220 (Device Type 350): stable and tested
• Precise rugged Temperature/Humidity Sensor EE08 (Device Type 360): stable and tested
• ToF Distance Sensor TeraRanger Evo (Device Type 370): stable and tested
• Precise Temperature/Humidity Sensor HC2 (Device Type 380): stable and tested
• MODBUS converter (here for E+H Radar Distance Sensor FMR20) (Device Type 390): stable and tested

todo:

• Docu
• More Sensors (planed):
  • other TOF/LIDAR Sensors for Distance Sensors
  • Simple Counter (eg. for Rain Counters)
  • Industrial Grade Particle Sensor (e.g SPS30)
  • ... *** Your contribution to this project is appreciated! ***

Hardware

Implementation with u-Blox ANNA-B112:

Real World Project with Time-of-Flight Distance sensor:

Real World Project with KKD-18:

Real World Project with Barometric Pressure Sensor MS5607:

Different Temperature/Humidity Sensors: SHT21 (3D-printed) or Industrial EE08 or HC2:

Companion Projects:

Link: SDI12Term - Simple Terminal for PC with simple RS232-Connector

Link: BlueShell - Shell for Windows 10 / 11 (free)

Link: BLE API Live (in Repository LTX BLE Demo)

Read the full story...

PDF: A real-world IoT project for rock monitoring in the Valais mountains (Switzerland)

Links

Some Facts about SDI-12:

• SDI-12 is a very simple protocol, mainly designed for Ultra-Low-Power Meteorolocical and Hydrological Sensors
• It is a simple 3-wire Bus and allows up to 10 (optionally 64) sensor nodes with 500 mtr. total cable length
• Although SDI-12 is now available in V1.4, V1.3 is still sufficient for almost all needs (simply ignore Chapters 5 and 6 in the Specs)
• SDI-12 communicates in a human readable format, a CRC16 can be used optionally
• Own Commands can be added very easily (e.g. for Calibration Coeffients)
• The Open-SDI12-Blue Hardware works from 2.8V(!) to 14V Supply (originally SDI-12 requires 9.6V to 14V Supply)
• SDI-12 was first released in 1988 and is free to use

Sponsors

This project was sponsered and supported by:

Link: TerraTransfer GmbH, Bochum, Germany

Installation

• Built with SES (V6.22a ()) and SDK 17.1.0 (: Later Versions of SES require changed project settings!!!)
• Based on JesFs

Use this Directory Structure:

C:\nordic\nRF5_SDK_17.1.0
+---components            // SDK
+---external              // SDK
+---integration           // SDK
+---open_projects
|   \---sdi_blue          // *HERE*
|       +---hardware
|       +---JesFs_Home
|       +---jw_libs
|       +---sensor_libs
|       +---sensor_types
|       +---Tools
|       \---Uni_BLE        

Links

• The SDI-12 Support Group: https://www.sdi-12.org
• Wikipedia: https://en.wikipedia.org/wiki/SDI-12

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