Introduction

Wanna slack off abit but scared to be busted? Here is the all-in-one wireless tripwire that help you automatically switch your computor program when motion is detected! Best of all, it uses MicroPython to program OpenMV so you can even add some "whitelist" using face recognition, and it also use RTL8722DM_MINI as the Bluetooth Keyboard, so you can even trigger a custom script upon motion detected~??

Demo

Project Details

A hearty combination of "Machine Vision" and "Bluetooth HID" function yields this "Office Tripwire" device.

How it works:

Essentially, it works by letting the OpenMV device to constantly comparing the current frame captured with the last frame, if the difference is greater than a set threshold, then a signal will be generate on a GPIO pin to alert the Ameba (AMB23 RTL8722DM), which then functions as a bluetooth keyboard and send a "Alt + Tab" keystroke over bluetooth to the connected device whose primary program will be switch to the next program.

Arduino Code

#include "BLEHIDDevice.h"
#include "BLEHIDKeyboard.h"
#include "BLEDevice.h"


BLEHIDKeyboard keyboardDev;
BLEAdvertData advdata;


#define ENABLE_PIN 9


void setup() {
  Serial.begin(115200);
  advdata.addFlags();
  advdata.addCompleteName("AMEBA_BLE_HID");
  advdata.addAppearance(GAP_GATT_APPEARANCE_HUMAN_INTERFACE_DEVICE);
  advdata.addCompleteServices(BLEUUID(HID_SERVICE_UUID));


  BLEHIDDev.init();


  BLE.init();
  BLE.configAdvert()->setAdvData(advdata);
  BLE.setDeviceName("AMEBA_BLE_HID");
  BLE.setDeviceAppearance(GAP_GATT_APPEARANCE_HUMAN_INTERFACE_DEVICE);
  BLE.configSecurity()->setPairable(true);
  BLE.configSecurity()->setAuthFlags(GAP_AUTHEN_BIT_BONDING_FLAG);
  BLE.configServer(3);
  BLE.addService(BLEHIDDev.hidService());
  BLE.addService(BLEHIDDev.battService());
  BLE.addService(BLEHIDDev.devInfoService());


  pinMode(ENABLE_PIN, INPUT);


  BLE.beginPeripheral();
}


int flag = 0;


void loop() {
  if (BLE.connected() && digitalRead(ENABLE_PIN) && flag == 0) {
    Serial.println("Sending keystrokes");
    keyboardDev.keyReleaseAll();
    delay(100);
    keyboardDev.keyPress(HID_KEY_ALT_LEFT);
    delay(100);
    keyboardDev.keyPress(HID_KEY_TAB);
    keyboardDev.keyReleaseAll();
    delay(100);
    flag = 1;
  } else {
    flag = 0;
    delay(100);
  }
}

Future Improvement:

The same function can be achieved by just using a PIR sensor. However, with OpenMV, you may add in a hint of AI by enabling the Face Recognition feature on OpenMV, then this device could potentially only triggers when a face that is not on the whitelist  is detected, making it actually useful and fun.

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PS: This project is also posted on Hackaday.io at

https://hackaday.io/project/183782-wireless-tripwire-with-machine-vision