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Fingerprint Identification With NodeJS Using U.are.U Devices
By Godwin Udofia in October 2022 ~ NodeJS

Scanners tested

This was tested with the U.are.U 4000B and 4500 scanners.

The DPFJ and DPFPDD libraries

I stumbled upon this library, that aims to allow communication between a nodejs application and the DLL/SO of the DPFJ and DPFPDD libraries created by DigitalPersona/HID Global.

Initializing the reader

Once the fingerprint reader is connected, it must first be initialized.

const { UareU, CONSTANTS } = require("uareu-node");

const uareu = UareU.getInstance();

let reader;

const initializeScanner = async () => {
  return await uareu
    .loadLibs("./bin/dpfpdd.dll", "./bin/dpfj.dll")
    .then(() => {
      uareu.dpfpddInit();
    })
    .then(async () => {
      const devices = await uareu.dpfpddQueryDevices();

      if (devices.devicesNumber > 0) {
        return devices;
      }
    })
    .then((res) => res && uareu.dpfpddOpen(res.devicesList[0]))
    .then((res) => res && (reader = res))
    .catch((err) => {
      throw err;
    });
};

The DLL files at .loadLibs("./bin/dpfpdd.dll", "./bin/dpfj.dll") are provided by DigitalPersona/HID Global

Fingerprint identification

The application: an ElectronJS application that captures fingerprints to record staff attendance.

const identifyForAttendance = async () => {
  await uareu.dpfpddCancel(reader);

  return await uareu.dpfpddCaptureAsync(
    reader,
    CONSTANTS.DPFPDD_IMAGE_FMT.DPFPDD_IMG_FMT_ANSI381,
    CONSTANTS.DPFPDD_IMAGE_PROC.DPFPDD_IMG_PROC_DEFAULT,
    identifyForAttendanceCallback
  );
};

const identifyForAttendanceCallback = async (data) => {
  uareu
    .dpfjCreateFmdFromFid(
      data,
      CONSTANTS.DPFJ_FMD_FORMAT.DPFJ_FMD_ANSI_378_2004
    )
    .then(async (res) => {
      let FMD_LIST = await AllFingerprints();
      let result;

      for (let index = 0; index < FMD_LIST.length; index++) {
        const fmd = FMD_LIST[index];

        result = await uareu.dpfjCompare(res, fmd);

        if (result.resultMessage === "Fingers match.") {
          await RecordAttendance(fmd.Staff);

          ipcMain.emit("staff:found", fmd);
          return;
        }
      }

      ipcMain.emit("staff:notfound");
    })
    .catch((error) => {
      console.log(error);
    });
};

Fingerprint enrolment

See this article to learn how to enrol fingerprints.

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