https://github.com/kenbell/giv-lora

https://github.com/kenbell/giv-lora

Last synced: about 2 months ago
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• Host: GitHub
• URL: https://github.com/kenbell/giv-lora
• Owner: kenbell
• Created: 2024-02-08T13:59:25.000Z (12 months ago)
• Default Branch: main
• Last Pushed: 2024-02-08T14:12:25.000Z (12 months ago)
• Last Synced: 2024-10-13T08:13:20.681Z (3 months ago)
• Language: Go
• Size: 502 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# giv-lora - protocol sniffing for GivEnergy LoRa modules

GivEnergy support their domestic battery systems reading solar generation over a LoRa link.  They recently changed the module used from 'GIV-LORA' which is a Heyuan IOT-L2S-B1 module, to 'GIV-LORA-LCD' with GivEnergy branding.

This repo consists of a description of the new 'GIV-LORA-LCD' [hardware](./HARDWARE.md) internally and the software required to sniff the broadcast LoRa communications.

## Getting Started

Familiarity with the Go programming language is assumed, since there is currently no configuration capabilities - the source code will likely need to be modified to your circumstances.

To get started, you'll need some readily-available hardware components for approx 35GBP.  See [Dongle Instructions](./DONGLE.md) for details on creating and flashing the firmware of a dongle.

* Plug in the prepared dongle

* Get the source: `git clone https://github.com/kenbell/giv-lora`

* Locate which UART/COM port the dongle is plugged into

* Find which channel the LoRa modules are using (press 'Func' button)

* Run the app from the `app` folder using `go run . -port  -ch `

If all is well a screen like this should appear and start populating:

![screenshot](./images/screenshot.png)

## LoRa

The end-user accessible LoRa configuration is limited to selecting 1 of 51 possible channels (frequencies).  The Spreading Factor and Bandwidth appear to be fixed.

* Header: Explicit

* Spreading Factor: 7

* Bandwidth: 125kHz

* Frequency: (51 channels, default 15)

   - Ch  0: 430.1 MHz

   - Ch  1: 430.3 MHz

   - Ch  2: 430.5 MHz

   - Ch  3: 430.7 MHz

   - Ch  4: 430.9 MHz

   - Ch  5: 431.1 MHz

   - ...

   - Ch 26: 435.3 MHz

   - ...

   - Ch 50: 440.1 MHz

    Formula: 430.1 MHz + ch * 200 kHz

## Protocol

The LoRa payload appears to be a proprietary protocol.  An example packet is: `88 41 3b c5 1a ff ff 10 01 66 b8 bb`

The fields are apparently:

  * Signature (2 bytes): `88 41`

  * Packet Seq No (1 byte): `3b`

  * Net ID(?) (2 bytes): `c5 1a`

  * Destination (2 bytes): `ff ff` (broadcast)

  * Source (2 bytes) `10 01`

  * Payload (variable): `66` 'f'

  * Checksum (2 bytes): `b8 bb`

The checksum is CRC Modbus 16 over the entire packet (excluding the checksum itself).

In this example, the payload was the single character 'f' - in practice it is one or more [modbus ADUs](https://en.wikipedia.org/wiki/Modbus#PDU_and_ADU).