In the datasheet, it had a hookup guide for each, so I made the necessary connections for 12V. The strike I found has four, because it was designed to be compatible with either a 12V or 24V power supply. You can plug in the power supply or turn on a surge protector into which it's plugged, and the strike should make a faint buzzing and the gate should transition from fixed to movable.ĭepending on your model, your electric strike may have two wires or four. Check the power supply to determine which wire is the positive and which is ground, then connect the wires to the electric strike in a temporary fashion with alligator clips. You can add a barrel jack connector if you wish, however I just cut the connector off the power supply and stripped the wires. Test the strike by connecting it to the 12V power supply. Now, when you swipe a tag, if it is approved then the relay board should activate for 3 seconds, illuminating an LED and making an audible click before shutting off. Be sure to change this in the python script if you use a different signal pin. The power and ground connections can be made to any 5V and GND pins, however I used Pin 2 for my 5V pin and Pin 4 for my ground. Since you should already have the RFID reader working at this point, I recommend connecting the relay board to the Pi as seen in the diagram below.
MAGNETIC CARD READER AND WRITER RASPBERRY PI SWIPE CODE
When a code is found, it will check if it is on the list of approved codes and either report the name of the associated user or report that the code wasn't found on the list. When run, the script should continuously monitor the RFID reader. The Python script requires root privileges in order to read signals from the RFID reader that is plugged in over USB, so run the script using the "sudo" prefix. Create a text file to contain the list of users and their IDs and copy over the test code supplied to get started. Next, set up your Raspberry Pi with the latest version of Raspbian OS and create a directory to work in. They read the RFID number, and then they output it as ASCII characters sequentially. This is because these USB RFID readers emulate a keyboard. If you open notepad and swipe, you'll see the tag's code appear. Its power light will illuminate, and if you swipe a tag over it, the reader will beep and the light will blink once. To start, connect your RFID reader over USB to a computer running Windows. Maybe writable would be cool on a future project, but I don't see a need for it on this one. You can also get writable tags to store information, but I just went with permanent tags bearing a simple ID number. The rest of this guide should apply regardless of which option you take, just be aware that all your RFID tags and all your RFID readers will need to match. I used 125kHz because that was what I initally bought, and the two seem functionally identical, but 13.56 seems slightly more common and thus easier to buy tags for. The cheap, questionably manufactured products I suggested come in either one. There are many others for advanced applications such as active RFID technology like that used in a car's remote keychain fob, but if you're looking to unlock a door, just get one of these. What I found, however, is that there are two dominant standards for basic applications: 125kHz and 13.56MHz. This question wasn't well addressed in the tutorials I used, and most guides on this are confusing. Suggestions for better sources are welcomed. I try to void shopping at Amazon and others exploitative marketplaces, but I don't know of a reputable source for these low-cost Chinese RFID readers, so I went with NewEgg. It's a ready-to-use solution at a very low price, so this is what I recommend. If you search for an RFID reader on any of these or just Google, you'll see dozens of the little black boxes you see below for anywhere from $5 to $20.
The last category consists of dozens and dozens of identical, cheap, Chinese electronics sold through Amazon, NewEgg, AliBaba, and the like. The second category includes ultra-premium products from RFID-focused engineering firms such as the Thingmagic Elara USB RFID reader from. These are all cost around $40 at least and require some technical knowledge to set up. Adafruit has an RFID shield for Arduino, and an assembled RFID reader with a PS/2 Interface. SparkFun has a couple of RFID antennas and compatible RFID boards. The first is as an antenna and board from the conventional DIY sellers. As of when I'm writing this in 2019, RFID readers come in three forms, if we discount hand-held readers and other devices that don't fit our use case.
One of the obstacles I faced when building this is the apparent immaturity of the DIY RFID market.
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