UHF UART Reader

UHF RFID reader module through UART interface designed for rk3128_box device.

Installation

To install run:

pnpm add uhf-uart-reader

or

npm install uhf-uart-reader

or

yarn add uhf-uart-reader

You will need to update your expo project to start going with a prebuilt android directory.

Running this command will generate the android directory:

pnpm expo prebuild --platform android

This is required because we want to modify the build.gradle file in this new directory to set the following:

android {
  ...
  defaultConfig {
    ...
    minSdkVersion = Integer.parseInt(findProperty('android.minSdkVersion') ?: '21')
        compileSdkVersion = Integer.parseInt(findProperty('android.compileSdkVersion') ?: '34')
        targetSdkVersion = Integer.parseInt(findProperty('android.targetSdkVersion') ?: '21')
  }
}

All this is needed because Expo SDK 50+ doesn't allow us to set the minSdkVersion and targetSdkVersion below 31, so we need to set it manually in the build.gradle file.

We also need to add abiFilters in defaultConfig to support armeabi-v7a and arm64-v8a:

android {
  ...
  defaultConfig {
    ...
    ndk { abiFilters "armeabi", "armeabi-v7a" }
  }
}

Once this is done, builds will work as expected.

Usage

connectUhfReader

This connects to the UHF reader on the given serial port and specified baud rate, starts reading in the background and returns a boolean indicating if the connection was successful.

import { connectUhfReader } from "uhf-uart-reader";

const connected = await connectUhfReader("/dev/ttyS0", 115200);

setReaderPower

This sets the power of the UHF reader, the power should be a number between 0 and 100.

import { setReaderPower } from "uhf-uart-reader";

setReaderPower(50);

addUhfListener

Note: This function should be called after connectUhfReader has been called.

This adds a listener to the UHF reader, the listener will be called every time a new tag is read.

import { addUhfListener } from "uhf-uart-reader";

addUhfListener((tag) => {
    console.log(`Tag EPC: ${tag.epc}`);
});

This returns a function that can be called to remove the listener.

disconnectUhfReader

This disconnects the UHF reader, it should be called when the reader is no longer needed.

import { disconnectUhfReader } from "uhf-uart-reader";

disconnectUhfReader();

isUhfReaderConnected

This returns a boolean indicating if the UHF reader is connected.

import { isUhfReaderConnected } from "uhf-uart-reader";

const connected = isUhfReaderConnected();

listSerialPorts

This returns a list of available serial ports on the device (the options that can be passed to connectUhfReader).

import { listSerialPorts } from "uhf-uart-reader";

const ports = await listSerialPorts();

listBaudRates

This returns a list of available baud rates that can be passed to connectUhfReader. The baud rates are hardcoded to the following values: [9600, 19200, 38400, 57600, 115200].

import { listBaudRates } from "uhf-uart-reader";

const baudRates = listBaudRates();