Briefing Paper Electronic door locks and access control Guy Kasier E&D Systems Available online January 2011 Source: DOM Home of the Future
Introduction Electronic door locks and access control Central locking is fitted as standard in most cars. You can lock and unlock your car from a distance by pressing the buttons on your car key. You no longer have to put the key into the lock and turn it. When locking or unlocking your car, you also get a visual indication from the flashing lights on the car. When you unlock it, the interior light will come on for a while if it is dark. This helps you to see the ignition lock properly. When we come home, things are generally different. We have to take a key out of our jacket pocket or handbag, push it into the cylinder lock of the front or back door, and turn it to open the door. This is a big difference in convenience compared to the door lock of your car. In this article, we look at the possibilities for using electronic locks and access control in houses and apartments. This could not only be an interesting addition for comfort and safety in the individual house or apartment, but in new or renovated homes for elderly people, the use of electronic locks could make the difference between being able to live alone independently, or moving to an old people s home or care centre. The conventional cylinder lock For many decades, the cylinder lock has been used to secure the home against unwanted visitors. In our hectic and sometimes complicated modern society, they sometimes have their disadvantages. If the key is lost, a new one has to be made by a locksmith. Even worse is when we have also given a key to an outsider who then disappears into the night (the cleaner, for example). In cases like this, we not only have to replace all the keys of the people living there, but also the cylinder locks. For elderly people with a shaky hand, it is often very difficult to get the key into the lock. Furthermore, with a conventional cylinder lock, it is not possible to operate the lock from a distance. This is a disadvantage for people with reduced mobility in particular. When somebody calls, it takes rather a long time before the resident can open the door manually. By this time, the postman may already have moved on. The conventional electric door lock You often see a conventional electric door lock at the main entrance of apartment buildings. They are connected to the intercom or videophone system. The resident only has to press a button on the internal set to activate the door lock for a few seconds. During this time, the visitor can open the door. The electric door lock is built into the doorpost and only opens and closes the latch. This is not an immediate disadvantage for the main entrance door of an apartment building. However, it is for an individual house or apartment. After all, here you also want to activate the double lock (the second protection), and that cannot be done with a regular electric lock. 1
A conventional electric door lock is installed in the doorpost. Generally a 12 or 24VAC supply voltage is required to energise the coil of the lock. Mechatronic cylinders A conventional cylinder lock can be easily replaced with a mechatronic version. A small battery and electronics are built into the cylinders of these locks. The key also has on-board electronics and often also a battery. The door can be opened by pushing the key into the cylinder lock. The electronic part examines whether or not this key can allow access. Only when these two match (the mechanical part and electronic part) can the door be opened by turning the key. This technique is not more convenient, but it is more secure. In large buildings, it can save the cost of installing the same cylinder locks everywhere by giving the same keys to all employees, but with access restrictions imposed in the electronic part to certain rooms for certain employees. For mechatronic cylinders, a key still has to be used. (Source: Dom) Digital cylinders One step further in the electronification of the door lock is the use of digital cylinders. They also have a battery and electronics. Depending on usage, the battery has a lifetime of two to five years. When the battery is almost empty, it is indicated by a flashing LED when, for example, opening the door. You then have enough time to replace the battery. Another method consists of refusing access for a while before the door can be opened. Conventional keys are generally not used with digital cylinders. The residents are given a transponder in the form of a credit card or a tag. A radio frequency identification (RFid) is incorporated into it. In order to gain access to the home, the transponder just has to be held in the vicinity of the digital lock. A green and red LED indicates whether or not access is granted. With ordinary digital cylinders, the user himself has to turn the button of the cylinder to actually open the lock. However, there are also digital cylinders that have a small motor. This version opens the lock automatically when the right transponder is presented. The battery lifetime is reduced to around one year as a result. 2
Most receivers have a small reception range. As a result the transponder has to be placed relatively close to the receiver to open the door. However, there are also systems with a larger detection range of a few metres. In these cases, the transponder can stay in the jacket pocket or handbag to open the door. The vicinity of the transponder carrier is sufficient to generate a response. A transponder can take on different forms. (Source: Dom) Depending on the application, digital cylinders are available in a number of varieties. (Source: Kaba) 3
Systems with door fittings Instead of just replacing the cylinder, it is also possible to replace the entire lock with door fittings. In most cases, they are systems that can be opened with a transponder. In certain cases, there is a keypad for entering a code. Generally, they are motorised systems that not only open and close the latch, but also automatically activate the double lock when the door is closed. These systems also use a battery. Two examples of door fittings with electronics for access control. (Source: Kaba) Other systems There are many other systems. One such method does not use a conventional transponder in the form of a card or tag, but the user s mobile phone, which unlocks the door when in the vicinity. For this, the mobile phone has to have Bluetooth communications facilities. Sometimes the vicinity of the right mobile telephone is sufficient to open the door. (Source: Sorex) 4
Access rights Depending on the version of digital cylinder used, access rights can be allocated according to time. The cleaner can, for example, only gain access to the home with her transponder on Thursdays between 8 and 12 am. The domestic nurse can only gain access from 7 to 10 am and from 4 to 8 pm every day. The meals on wheels service can make its delivery between 11:30 and 13:00. From standalone to... The solutions described above are standalone applications. Every cylinder has to be programmed separately. The cylinder locks do not communicate with the outside world. Things change, however, when we add a communication module to the system. It can be built into a standard recessed box in the vicinity of a digital cylinder. This communicates with the communication module using RF. Depending on the make and version, the communication modules have one or more input contacts, one or more output contacts, or an Ethernet connection. The input contact enables a lock to be operated remotely. This can be done, for example, with a standard pushbutton, a button on the interior intercom or videophone set, a contact in an integrated home system, or a personal alarm system (PAS). Other sensors can also be connected to the input contacts such as a fingerprint reader or a magnetic contact. The above drawing shows RF communications between the communication module and the digital cylinder. A magnetic contact and a fingerprint reader are also connected. However, when the door is left open, the communication module will send a signal to an alarm system. (Source: Dom) If there is an Ethernet connection, it is also possible to operate or reprogramme the lock from outside the home. This is especially important for homes or housing units for single elderly people. When an alarm is given via the PAS system, rapid response care providers can gain access with their transponder. A person who does not have access rights to the home at certain times (for example, at nights) can still be given access rights in an alarm situation. To this end, the digital cylinder lock is temporarily reprogrammed for the care providers who come to assist. They then gain temporary access to the home. 5
The output contacts of the communication module can also be used to make the lighting come on when somebody opens the lock, or to put an alarm system into operation when somebody tries to open the door with an incorrect transponder. The programming In standalone applications, the digital lock is programmed in the vicinity of that digital lock by a programming unit. In systems with an Ethernet connection, it is possible to do the programming from any location with a computer program. As a result of the programming, it is possible to allocate transponders to certain locks, and with time registration. It is then possible to examine who opened what door at what time. This is, of course, only used in large buildings. On the left, there is a manual programming unit, and on the right, a computer screen for access control in large buildings.(source: Kaba, Simons Voss) In the event of the loss or theft of transponders, the locks do not need to be replaced. It is sufficient to just deprogramme the lost transponder. This can then no longer be used by other people. A new transponder can be created at the same time. Other access control systems For homes and housing units, biometric readers (fingerprint and iris recognition) are rarely used because they are too expensive and too complex. In large buildings, they crop up more often. They are primarily used when the security level of a building or certain rooms in a building must be at a very high level. Some houses, and certainly many apartments, feature keypads for entering a code. This generally consists of a module with keys for the figures 0 to 9 and a few additional keys (such as a confirmation key). By entering the right code, a conventional electric lock is activated. However, there are some disadvantages attached to keypads. First of all, the users have to learn a code by heart (in addition to other codes for bank cards, PINs for mobile telephones, codes for accessing internet sites, etc). For some users, this can be a problem. Furthermore, a code can be passed on to anybody, and when a resident moves from an apartment, the code is often not changed. As a result, non-residents can easily gain access to the 6
building. The keys of a keypad are open to dust and dirt. When everyone is always typing in the same code, over the course of time it can be clearly seen which numbers form the code. Entering the code removes some of the dirt and dust from those keys, but leaves the others to grow darker with dirt. This makes it easier to crack the code. A keypad. (Source: Nice) Conclusion Our cars have central locking so that we can operate the lock from a certain distance with the buttons on the car key. This not only increases security, but also convenience and ease of use. In our house or apartment, we often use conventional keys to gain access. The difference is considerable. For elderly people with a shaky hand, conventional keys are difficult to use. For other people it can also be difficult to find the keyhole in a darker environment. By installing electronic locks, it all becomes much easier. If a communication module is also installed, the possibilities are even greater. In such cases, external sensors, actuators and integrated home systems can be connected to the system and the programming and granting of access can be done remotely. 7