react-native-soil-device-sdk

React Native SDK for a USB Type‑C soil sensor cable (CH34x/CH340) that talks Modbus‑RTU over USB Serial and (optionally) reports readings to your server with an offline queue.

Android only. USB Host / OTG is required. iOS does not allow generic USB-serial access in normal apps.

What you get

• List USB serial devices (CH34x/CH340 preferred)
• Connect / disconnect
• Read 8 soil parameters from Modbus holding registers 0x0000–0x0007:
  • temp (°C), hum (%), EC (µS/cm), salinity (mg/L), N/P/K (mg/kg), pH
• Optional: API-key verification (/api/verify) and reporting (/api/data) with offline FIFO queue

Install

npm i react-native-soil-device-sdk
# or
yarn add react-native-soil-device-sdk

Peer deps you must install (for offline queue + online detection):

yarn add @react-native-async-storage/async-storage @react-native-community/netinfo

Android setup

1) Enable USB host

android/app/src/main/AndroidManifest.xml

<uses-feature android:name="android.hardware.usb.host" />

<application
  android:usesCleartextTraffic="true"
  ... />

2) (Recommended) Add USB intent filter (auto-open your app when the cable plugs in)
Create android/app/src/main/res/xml/soil_device_filter.xml in your app:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <!-- WCH CH340/CH341 -->
  <usb-device vendor-id="6790" />
</resources>

Then add this inside your MainActivity in the app manifest:

<intent-filter>
  <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
</intent-filter>

<meta-data
  android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
  android:resource="@xml/soil_device_filter" />

Quick start

import { SoilDeviceSdk, SoilDeviceClient } from "react-native-soil-device-sdk";

// 1) Configure once at app startup
SoilDeviceSdk.configure({ apiKey: "YOUR_API_KEY" });

// 2) Create a client
const client = new SoilDeviceClient({
  mode: "once",
  proactiveReportingSeconds: 2,
  slaveId: 1
});

// 3) List, connect, read
const devices = await client.getDeviceList();
await client.makeConnection(devices[0]);

const data = await client.getPrintingValue();
console.log(data);

State management examples

See: example/src/state/*

• useState / hooks: example/src/App.useState.tsx
• Context + useReducer: example/src/state/context/*
• Redux Toolkit: example/src/state/redux/*
• Zustand: example/src/state/zustand/*
• MobX: example/src/state/mobx/*
• Recoil: example/src/state/recoil/*

Notes / limitations

• You must physically plug the USB sensor in and accept the Android permission prompt.
• On some devices, manufacturer/product names are only available after permission is granted.