# Grove 125KHz RFID Reader ![](https://raw.githubusercontent.com/SeeedDocument/Grove-125KHz_RFID_Reader/master/img/Grove-125KHz_RFID_Reader.jpg) This Grove-125KHz RFID Reader is a module used to read uem4100 RFID card information with two output formats: Uart and Wiegand. It has a sensitivity with maximum 7cm sensing distance. There is also [the electronic brick version](http://www.seeedstudio.com/depot/electronic-brick-125khz-rfid-card-reader-p-702.html?cPath=52) of this module. It can help you with project like internet of thing and access control system. And you should use the module below while using RFID reader: * [RFID tag combo (125khz)](http://www.seeedstudio.com/depot/rfid-tag-combo-125khz-5-pcs-p-700.html?cPath=19_24) [![](https://raw.githubusercontent.com/SeeedDocument/common/master/Get_One_Now_Banner.png)](http://www.seeedstudio.com/depot/grove-125khz-rfid-reader-p-1008.html) ## Specifications * Voltage: 4.75-5.25V * Working Frequency: 125 KHz * Sensing Distance(Max): 70mm * TTL Output: 9600 baudrate, 8 data bits, 1 stop bit, and no verify bit * Wiegand Output: 26 bits Wiegand format, 1 even verify bit, 24 data bits, and 1 odd verify bit !!!Tip More details about Grove modules please refer to [Grove System](http://wiki.seeed.cc/Grove_System/) ## Platforms Supported ## Demonstration Here we show how to read RFID information using the Grove - 125KHz RFID Reader. Connect Grove - 125KHz RFID Reader to UART of Grove - Base Shield. ![](https://raw.githubusercontent.com/SeeedDocument/Grove-125KHz_RFID_Reader/master/img/RFID_reader.jpg) ### Uart Mode (Jumper set to the left two pins) You would need to select the jumper to "U" to enter this mode, and the setting is: 9600bps, N, 8, 1, TTL output ```c /* link between the computer and the SoftSerial Shield at 9600 bps 8-N-1 Computer is connected to Hardware UART SoftSerial Shield is connected to the Software UART:D2&D3 */ #include SoftwareSerial SoftSerial(2, 3); unsigned char buffer[64]; // buffer array for data receive over serial port int count = 0; // counter for buffer array void setup() { SoftSerial.begin(9600); // the SoftSerial baud rate Serial.begin(9600); // the Serial port of Arduino baud rate. } void loop() { // if date is coming from software serial port ==> data is coming from SoftSerial shield if (SoftSerial.available()) { while(SoftSerial.available()) // reading data into char array { buffer[count++] = SoftSerial.read(); // writing data into array if(count == 64)break; } Serial.write(buffer, count); // if no data transmission ends, write buffer to hardware serial port clearBufferArray(); // call clearBufferArray function to clear the stored data from the array count = 0; // set counter of while loop to zero } if (Serial.available()) // if data is available on hardware serial port ==> data is coming from PC or notebook SoftSerial.write(Serial.read()); // write it to the SoftSerial shield } void clearBufferArray() // function to clear buffer array { // clear all index of array with command NULL for (int i=0; i