diff --git a/README.md b/README.md
index bfc0450..437ffd8 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,45 @@
-# homebridge-gpio-electromagnetic-lock
+# Homebridge GPIO Electromagnetic Lock
 Homebridge plugin to control electromagnetic lock via Raspberry Pi GPIO pins.
+
+## Motivation
+I haven't found similar script working with Raspberry Pi GPIO.
+
+## Installation
+1. install homebridge
+   `npm install -g homebridge`
+2. install this plugin
+   `npm install -g homebridge-gpio-electromagnetic-lock`
+3. update your `~/.homebridge/config.json` file (use `sample-config.json` as a reference)
+
+## Configuration
+Sample accessory:
+```
+"accessories": [
+  {
+    "accessory": "ElectromagneticLock",
+    "name": "Lock",
+    "lockPin": 5,
+    "doorPin": 16,
+    "activeLow": false,
+    "reedSwitchActiveLow": false,
+    "unlockingDuration": 2,
+    "lockWithMemory": true
+  }
+]
+```
+
+Fields:
+
+- `accessory` must always be *ElectromagneticLock*
+- `name` accessory name, e.g. *Lock*
+- `lockPin` pin for unlocking lock (use *gpio numbering*, not *physical*)
+- `doorPin` [optional] door contact sensor, ignored when *lockWithMemory* is set to false
+- `activeLow` [optional, default: *true*] true: relay activated by low state (0), false: relay activated by high state (1), affects *lockPin*
+- `reedSwitchActiveLow` [optional, default: *true*] true: reed switch activated by low state (0), false: reed switch activated by high state (1), affects *doorPin*
+- `unlockingDuration` [optional, default: *2*] how long *lockPin* should be active (seconds)
+- `lockWithMemory` [optional, default: *true*] true: electromagnetic lock that stays unlocked until full door cycle, false: stays unlocked only for *unlockingDuration* seconds
+
+## Troubleshooting
+- check platform: [Homebridge](https://github.com/nfarina/homebridge)
+- check plugin dependency: [rpio](https://www.npmjs.com/package/rpio)
+- or create issue
diff --git a/config-sample.json b/config-sample.json
index 96a2bbd..fd6ebd0 100644
--- a/config-sample.json
+++ b/config-sample.json
@@ -13,7 +13,9 @@
       "lockPin": 5,
       "doorPin": 16,
       "activeLow": false,
-      "reedSwitchActiveLow": false
+      "reedSwitchActiveLow": false,
+      "unlockingDuration": 2,
+      "lockWithMemory": true
     }
   ]
 }
diff --git a/index.js b/index.js
index 87d768b..58ad22b 100644
--- a/index.js
+++ b/index.js
@@ -16,7 +16,7 @@ module.exports = function(homebridge) {
 }
 
 function ElectromagneticLockAccessory(log, config) {
-  _.defaults(config, {activeLow: true, reedSwitchActiveLow: true});
+  _.defaults(config, {activeLow: true, reedSwitchActiveLow: true, unlockingDuration: 2, lockWithMemory: true});
 
   this.log = log;
   this.name = config['name'];
@@ -25,8 +25,8 @@ function ElectromagneticLockAccessory(log, config) {
   this.initialState = config['activeLow'] ? rpio.HIGH : rpio.LOW;
   this.activeState = config['activeLow'] ? rpio.LOW : rpio.HIGH;
   this.reedSwitchActiveState = config['reedSwitchActiveLow'] ? rpio.LOW : rpio.HIGH;
-  this.pollTransition = config['reedSwitchActiveLow'] ? rpio.POLL_LOW : rpio.POLL_HIGH;
-  this.doorWasOpenedAfterUnlocking = false;
+  this.unlockingDuration = config['unlockingDuration'];
+  this.lockWithMemory = config['lockWithMemory'];
 
   this.cacheDirectory = HomebridgeAPI.user.persistPath();
   this.storage = require('node-persist');
@@ -39,7 +39,12 @@ function ElectromagneticLockAccessory(log, config) {
     this.currentState = cachedCurrentState;
   }
 
-  this.targetState = this.currentState;
+  this.lockState = this.currentState;
+  if (this.currentState == STATE_UNKNOWN) {
+    this.targetState = STATE_SECURED;
+  } else {
+    this.targetState = this.currentState;
+  }
 
   this.service = new Service.LockMechanism(this.name);
 
@@ -47,21 +52,23 @@ function ElectromagneticLockAccessory(log, config) {
   this.infoService
     .setCharacteristic(Characteristic.Manufacturer, 'Radoslaw Sporny')
     .setCharacteristic(Characteristic.Model, 'RaspberryPi GPIO Electromagnetic Lock')
-    .setCharacteristic(Characteristic.SerialNumber, 'Version 1.0.3');
+    .setCharacteristic(Characteristic.SerialNumber, 'Version 1.1.0');
+
+  this.unlockTimeout;
 
   // use gpio pin numbering
   rpio.init({mapping: 'gpio'});
   rpio.open(this.lockPin, rpio.OUTPUT, this.initialState);
+
+  if (this.doorPin && !this.lockWithMemory) {
+    this.log("Electromagnetic lock without memory doesn't support doorPin, setting to null. Consider using separate contact sensor.");
+    this.doorPin = undefined;
+  }
+
   if (this.doorPin) {
     rpio.open(this.doorPin, rpio.INPUT);
-    if (this.currentState == STATE_UNSECURED) {
-      this.log('Lock is unsecured, waiting for door cycle.');
-      this.doorWasOpenedAfterUnlocking = true;
-      try {
-        rpio.poll(this.doorPin, this.secureLock.bind(this), this.pollTransition);
-      } catch (error) {
-        this.log('Door is already polling for events.')
-      }
+    if (this.lockWithMemory) {
+      rpio.poll(this.doorPin, this.calculateLockWithMemoryState.bind(this));
     }
   }
 
@@ -76,16 +83,6 @@ function ElectromagneticLockAccessory(log, config) {
 }
 
 ElectromagneticLockAccessory.prototype.getCurrentState = function(callback) {
-  if (this.isDoorOpen()) {
-    this.targetState = STATE_UNSECURED;
-    this.currentState = STATE_UNSECURED;
-    this.doorWasOpenedAfterUnlocking = true;
-    try {
-      rpio.poll(this.doorPin, this.secureLock.bind(this), this.pollTransition);
-    } catch (error) {
-      this.log('Door is already polling for events.')
-    }
-  }
   this.log("Lock current state: %s", this.currentState);
   callback(null, this.currentState);
 }
@@ -96,64 +93,75 @@ ElectromagneticLockAccessory.prototype.getTargetState = function(callback) {
 }
 
 ElectromagneticLockAccessory.prototype.setTargetState = function(state, callback) {
-  if (state) { // can't lock electromagnetic with memory
-    callback(null, this.currentState);
-    return false;
-  }
-
-  this.log('Setting lock to UNSECURED');
-
-  rpio.write(this.lockPin, this.activeState);
-  this.service.setCharacteristic(Characteristic.LockCurrentState, state);
-  this.currentState = state;
-  this.targetState = state;
-  this.storage.setItemSync(this.name, this.currentState);
-  rpio.sleep(2);
-  rpio.write(this.lockPin, this.initialState);
-  if (this.doorPin) {
-    if (rpio.read(this.doorPin)) {
-      this.doorWasOpenedAfterUnlocking = true;
-      rpio.poll(this.doorPin, this.secureLock.bind(this), this.pollTransition);
-    } else {
-      rpio.poll(this.doorPin, this.waitForDoorCycleAndSecureLock.bind(this));
-    }
+  this.log('Setting lock to %s', state ? 'secured' : 'unsecured');
+  if (state && this.lockWithMemory) {
+    this.log("Can't lock electromagnetic lock with memory.");
+    this.service.updateCharacteristic(Characteristic.LockCurrentState, state);
+    setTimeout(function() {
+      this.service.updateCharacteristic(Characteristic.LockTargetState, this.targetState);
+      this.service.updateCharacteristic(Characteristic.LockCurrentState, this.currentState);
+    }.bind(this), 500);
+    callback();
+  } else if (state && !this.lockWithMemory) {
+    clearTimeout(this.unlockTimeout);
+    this.secureLock();
+    callback();
   } else {
-    this.log('Setting lock to SECURED');
-    this.service.setCharacteristic(Characteristic.LockTargetState, STATE_SECURED);
-    this.service.setCharacteristic(Characteristic.LockCurrentState, STATE_SECURED);
-    this.currentState = STATE_SECURED;
-    this.targetState = STATE_SECURED;
-    this.storage.setItemSync(this.name, this.currentState);
+    rpio.write(this.lockPin, this.activeState);
+    this.service.setCharacteristic(Characteristic.LockCurrentState, state);
+    this.lockState = state;
+    this.storage.setItemSync(this.name, this.lockState);
+    this.unlockTimeout = setTimeout(this.secureLock.bind(this), this.unlockingDuration*1000);
+    callback();
   }
-
-  callback();
 }
 
-ElectromagneticLockAccessory.prototype.waitForDoorCycleAndSecureLock = function() {
+ElectromagneticLockAccessory.prototype.calculateLockWithMemoryState = function() {
   rpio.msleep(20);
-  if (rpio.read(this.doorPin)) {
-    this.doorWasOpenedAfterUnlocking = true;
-    return;
+  let doorOpen = rpio.read(this.doorPin) ? true : false;
+  if (doorOpen && this.lockState == STATE_UNSECURED) {
+    this.log('Door has been opened, lock: secured, current state: unsecured.');
+    this.lockState = STATE_SECURED;
+    this.currentState = STATE_UNSECURED;
+    this.targetState = STATE_UNSECURED;
+  } else if (doorOpen && this.lockState == STATE_SECURED) {
+    this.log('Door has been opened, lock already secured, current state: unsecured.');
+    this.currentState = STATE_UNSECURED;
+    this.targetState = STATE_UNSECURED;
+  } else if (!doorOpen && this.lockState == STATE_SECURED) {
+    this.log('Door has been closed, lock already secured, current state: secured.');
+    this.currentState = STATE_SECURED;
+    this.targetState = STATE_SECURED;
+  } else if (!doorOpen && this.lockState == STATE_UNSECURED) {
+    this.log('Door has been closed, lock: unsecured, current state: unsecured.');
+    this.currentState = STATE_UNSECURED;
+    this.targetState = STATE_UNSECURED;
+  } else {
+    this.log('State unknown, door open: ' + doorOpen + ', lock state: ' + this.lockState);
+    this.lockState == STATE_UNKNOWN;
+    this.currentState = STATE_UNKNOWN;
   }
-  this.secureLock();
-}
-
-ElectromagneticLockAccessory.prototype.secureLock = function() {
-  if (!this.doorWasOpenedAfterUnlocking) {
-    return;
-  } 
-  this.log('Setting lock to SECURED');
-  this.service.setCharacteristic(Characteristic.LockTargetState, STATE_SECURED);
-  this.service.setCharacteristic(Characteristic.LockCurrentState, STATE_SECURED);
-  this.currentState = STATE_SECURED;
-  this.targetState = STATE_SECURED;
+  this.service.updateCharacteristic(Characteristic.LockTargetState, this.targetState);
+  this.service.updateCharacteristic(Characteristic.LockCurrentState, this.currentState);
   this.storage.setItemSync(this.name, this.currentState);
-  this.doorWasOpenedAfterUnlocking = false;
-  rpio.poll(this.doorPin, null);
 }
 
-ElectromagneticLockAccessory.prototype.isDoorOpen = function() {
-  return this.doorPin && rpio.read(this.doorPin);
+ElectromagneticLockAccessory.prototype.secureLock = function() {
+  rpio.write(this.lockPin, this.initialState);
+    if (!this.doorPin && !this.lockWithMemory) {
+      this.service.updateCharacteristic(Characteristic.LockTargetState, STATE_SECURED);
+      this.service.updateCharacteristic(Characteristic.LockCurrentState, STATE_SECURED);
+      this.currentState = STATE_SECURED;
+      this.targetState = STATE_SECURED;
+      this.storage.setItemSync(this.name, this.currentState);
+    } else if (!this.doorPin && this.lockWithMemory) {
+      this.service.updateCharacteristic(Characteristic.LockTargetState, STATE_SECURED);
+      this.service.updateCharacteristic(Characteristic.LockCurrentState, STATE_SECURED);
+      this.service.updateCharacteristic(Characteristic.LockCurrentState, STATE_UNKNOWN);
+      this.currentState = STATE_UNKNOWN;
+      this.targetState = STATE_SECURED;
+      this.storage.setItemSync(this.name, this.currentState);
+    }
 }
 
 ElectromagneticLockAccessory.prototype.getServices = function() {
diff --git a/package.json b/package.json
index 5941960..8904504 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "homebridge-gpio-electromagnetic-lock",
-  "version": "1.0.3",
+  "version": "1.1.0",
   "description": "Homebridge plugin to control electromagnetic lock via Raspberry Pi GPIO pins",
   "license": "MIT",
   "keywords": [