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The fingerprint sensor is combination of R305 FP+PIC MCU board that can read different fingerprints and store in its own flash memory. The sensor can perform three functions namely Add(Enroll) , Empty Database or Search Database and return the ID of stored fingerprint.
Any of three functions can be called simply by making the pin low of the sensor or pressing onboard three switches. The response is either error or ok which is indicated by onboard LED. The response is also returned as single serial data byte. The return byte is a valid ID or error code. The response byte is a single byte at 9600 bps thus making whole sensor very easy to use. We have provided indicating LEDs and function switch already so it s ready to use when you receive it. Just give power and start using the sensor using onboard switches. Then you can move on making external application using these functions.
Features
Easy to use
Status LEDs
Function Switches
Single byte response
Works at 5V
UART 9600bps response
Inputs and Outputs of Sensor
Input: Two ways to trigger the function of fingerprint sensor
Onboard switch: Add, Empty or Search.
Make pin low from external microcontroller for 5ms as per function required to be executed.
Outputs(Response): Two ways to monitor output response after a function is executed
Onboard LEDs: ERROR or OK
Read byte after executing function
Types of function
There are namely three functions you can call for the fingerprint sensor. We will see each in brief.
Add(Enroll) Function: Adds a fingerprint to database and return a byte of newly added ID. Return values are from 0x00 to 0xFE. In case of error like no finger placed, return code is 0xFF. Here 0xFF means error executing function
Search Function: When a finger is put and search funtion is called, it returns a matching ID if found in its existing memory. Return values are from 0x00 to 0xFE. In case of error like no finger placed, return code is 0xFF. Here 0xFF means error executing function.
Empty Function: When you wish to empty all fingerprint data stored on sensor you can use this function. After executing this function, you will get 0xCC as OK or 0xFF in case of error.
Application Example
We will use an example of AT89S52 MCU to interface but can be any MCU like AT89C51 or AVR or PIC. Since the sample code is in C language. The logic will remain same across all C compilers.
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Fingerprint Scanning Section: This involves scanning the finger and generating a template corresponding to the alignment of ridges and valleys present in a fingerprint image. This template becomes a character file and will be stored in your database.
Fingerprint search section: This includes identifying a fingerprint by searching for each template that is stored in your database. The fingerprint to be identified will compare all the templates and generate positive or negative recognition. In today's safe world bio-metric security is at the top. Unlike other techniques that make use of passwords and numbers, which are necessary to be remembered, bio-metric techniques make use of human body parts like fingerprints or even irises of your eyes and as we know these things are unique to all by Which makes bio-metric systems the most effective over others. In this project I connected a very popular R305 fingerprint scanner with AtMega 16 micro-controller. This module communicates through the UART protocol with the micro-controller, ie it makes use of Rx and Tx pin of the micro-controller to interact with it.
Now talking about this module, comes preloaded with the scanner as well as the detection section and we are left with 4 pins for the connections. These 4 pins are: VCC, GND, Rx and Tx. It works on 3.3 to 5V supply and its Rx and Tx pin connects to the Tx and Rx pin of the micro-controller respectively. The mode is semi-duplex for serial communication asynchronous and the default transmission speed is 57600bps, but can be changed between 9600 115200bps.
When powering up, it takes approximately half a second to initialise, during this period the module can not accept commands. The system sets aside a 512-byte memory (16 pages x 32 bytes) for the user's notebook, where data that requires shutdown protection can be stored. There is an image buffer and two 512-byte buffers in the RAM space of the module. This buffer is used for image storage and the image format is 256 * 288 pixels. You can use two character file buffers to store both the character file and the template file. The system leaves aside some space within Flash for storing fingerprint templates, it's a fingerprint library. It is not volatile by nature. This module also serves the purpose of providing any random number of 32 bits.
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hi am sudam bhagwat i want the c code for interfacing R305 with PIC18F4520
