Automated Home Access Using RFID By: Harrizon Sanchez Travis AFB, California Good afternoon. I am Harrizon Sanchez , one of your off campus classmates. I am from Fairfield , California. Today I will be presenting my project about Automated Home Access using radio frequency identification (RFID). (NEXT SLIDE)

Overview Background Project Summary Phidgets RFID reader Electronic Door Strike Powerbolt 1000 Electronic Deadbolt Control Circuit Circuit Diagrams Conclusions I will talk about: Background about my project. Then I will give you a brief summary . Then I’ll give a quick description of the major parts of the project , specifically the Phidgets RFID reader, electronic door strike, electronic dead bolt, and its modified control circuit. Then next, I will show you the circuit diagrams I used to wire my project together and then proceed to conclusion. So lets begin (NEXT SLIDE)

Background Never used RFID before Ideas for RFID application Lots of material available on line Wanted to learn new concept Ideas for RFID application Pet identification Supply chain management Passport protection Access control I have never used an RFID before. And since this class is about getting out and learning new material about automation, I decided to do an RFID project and learn new concept, at least a new concept to me. So when it was mentioned in class, it caught my attention and I did some reading about it. I thought at first , where am I going to find my self a reader, am I going to have to build one? So I Googled RFID and there’s tons of information about RFID online . So what is RFID? Basically, radio-frequency identification is a technology that uses communication through the use of radio waves to exchange data between a reader and an electronic tag attached to an object, for the purpose of identification and tracking. What are some applications? It is used for pet identification, supply chain management, passport protection, access control, automation… etc. (NEXT SLIDE)

Project Summary Build a RFID Control Box Use a Phidgets RFID reader to detect tags Use DPDT Relay to activate electronic strike & deadbolt Modify control circuit of electronic deadbolt Use laptop to control access to the door So what did I do for this project? I built an RFID control box that contains my RFID reader that detects tags and uses a relay to activate the electronic strike and deadbolt. I also modified the electronic deadbolt circuit so it will retract the bolt when RFID sense an authenticated tag. And finally, used my laptop to control access to the door. I did this by compiling a VB code I downloaded online, which allowed my reader to only accept tags during certain times as indicated on my Access database. (NEXT SLIDE)

Phidgets RFID Reader Reads tags brought within 3 inches of the reader Reads any tag with EM4102 protocol On-Board LED Board connects directly to a computer’s USB port Drivers and source code for sample application The RFID reader I used is a Phidgets RFID reader. It has a USB connector which allows it to be programmed and connected to a computer. It reads tag brought within 3 inches provided the tags are compatible with EM4102 protocol. For this application , I ordered 2 passive 125 KHz clamshell type cards to play around with. They are about the size of a credit card, but thicker to accommodate larger wire coil antenna. This type of tag is usually used for low-frequency applications, such as this project. One thing about the RFID reader (and any hardware plugged in to a computer) is that you have to make sure you have the correct version of drivers and library installed in your computer for it to work. I learned this the hard way and took me a while to realize that the drivers I installed were not meant for this version of the reader. Hence, the source code that I downloaded didn’t work the first time. (NEXT SLIDE)

Output Screen for the Software Here are sample outputs when I finally got the correct version of drivers and library for my RFID reader. By the way the code I downloaded was named “DooRFID”. It can be modified to do a lot of stuff other than just telling a relay to open and close a circuit. Like sending an email notification, tracking how many times a door has been accessed etc… But since I am a beginner with this , I just started with the basic s; but I am definitely going to expand this project when I get the chance. Real quick, the first box shows you that the reader is scanning for tags. The second box, shows you the interface where you can program the RFID to allow certain tags to access the door only at certain times. Then the third box, lets you know if you are granted permission or not after you hover your tag over the RFID control box. (NEXT SLIDE)

Electronic Door Strike Mortise Type Accepts variable AC or DC voltage Power Source 16VAC Power Supply rated at 10VA I used a regular electronic door strike on this project. Nothing special. But just in case you are not aware, most access-control solutions use some type of an electronic door strike, which gives way when activated so you don’t‘ have to unlock or turn the door knob, you just push or pull the door to open. It works by having the AC power rush through the magnetic coil windings inside the door strike, pulling up and vibrating the pin that normally keeps the strike in a closed and locked position. The one I used for my project uses 16 VDC , hence I had to find a power supply that matches my electronic door strike. (NEXT SLIDE)

Powerbolt 1000 Electronic Deadbolt Control box has open and close switch that made the hack easier Has an option for standard key in case batteries die Automatic door locking after 30 seconds What is so special about this specific type of electronic deadbolt? I have gone to five different stores and none of the electronic deadbolts have a open and close switch imbedded on their control circuit which makes it very difficult to gain control or hack the control circuit of the electronic deadbolt. Powerbolt 1000 was the only one that had an open and close switch or button , that made my effort to control this device very less painful. As you can see on the picture, I showed the open and close button and I’ll show you on the next slide how I wired or modified the control circuit. (NEXT SLIDE)

Control Circuit Close & Open Switch 5V Reed Relay Electrolytic Capacitor Resistor To make this work, I needed a relay, a capacitor and a resistor. The diagram is pretty self explanatory. It looks something like this picture when wired. But let me share real quick why we used these components. The electronic dead bolt’s embedded open button --if you can imagine an actual button-- is designed so the dead bolt would open after the button is pressed and then released, not as soon as it is pressed. That means the RFID control box relay will not open the deadbolt until the relay is switched back off, which means the deadbolt will retract, but the electronic strike will be locked again, since the circuit is open and no current is flowing to its magnetic windings. Hence the cheap way of mitigating this, instead of rigging a timer circuit , is to use another relay for the open button, a capacitor and a resistor. When the reed relay is activated, it closes or “presses” the open button circuit. The capacitor is quickly saturated and current stops flowing. At that point reed relay opens, simulating the act of releasing the open button, then the bolt retracts. The 10K ohms resistor allows the capacitor to discharge once the power is cut from the circuit. If the resistor was not there, the capacitor could not discharge and would remain saturated, meaning you could only unlock the deadbolt once every 5 to 10 minutes. (Next Slide)

Circuit Diagram The circuit diagram on top shows the connection for the RFID control box (which you saw how it looks like on Slide 4) to the electronic strike power source and electronic strike and to deadbolt circuit. Notice the protection diode across the relay’s coil pins. The protection diode is necessary to sink the high voltage currents generated when the relay is switched off. If not protected, the high voltage spike has no place to go except through the circuit the relay is connected to and can end up damaging the circuit components. The one at the bottom shows how the power source and electronic strike are wired to the RFID control box. And from the previous slide I showed you how the electronic deadbolt circuit is wired to the RFID control box. (NEXT SLIDE)

Conclusions Correct/updated drivers for RFID reader Have the latest library for RFID reader before compiling your code Beyond just opening door Tags need to be compatible / same protocol before they can be recognized by a specific RFID reader These pictures shows the set up once both access control measures --the electronic strike and electronic deadbolt-- are connected to the RFID control box. Now this is just to show you the concept, but in real world application, you'd have to wire the door to where wires are secured and probably harden the control box. So in conclusion, I really had fun doing this project and really looking towards expanding it , to include email notification capability and remote access through my home network. But that will probably happen when I have extra cash. Lessons I learned from doing this project: The importance of making sure you have the correct or updated drivers and library for your components, and making sure your RFID reader and tags are compatible, i.e. supports the same protocol. (NEXT SLIDE)

Questions? Email sanc5183@vandals.uidaho.edu If you have any questions about this project you can email me here. Again I am Harrizon Sanchez, and thanks for listening.