Saturday, April 19, 2008

FingerPrint Based Security System

Personal Safes are revolutionary locking storage cases that open with just the touch of your finger. These products are designed as "access denial" secure storage for medications, jewelry, weapons, documents, and other valuable or potentially harmful items.These utilize fingerprint recognition technology to allow access to only those whose fingerprints you choose. It contains all the necessary electronics to allow you to store, delete, and verify fingerprints with just the touch of a button. Stored fingerprints are retained even in the event of complete power failure or battery drain.These eliminates the need for keeping track of keys or remembering a combination password, or PIN. It can only be opened when an authorized user is present, since there are no keys or combinations to be copied or stolen, or locks that can be picked. k
eeping track of keys or remembering a combination password, or PIN. It can only be opened when an authorized user is prese
nt, since there are no keys or combinations to be copied or stolen, or locks that can be picked.
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Monday, December 10, 2007

DS1820 Based High Precision Temperature Indicator

This project is an High precision digital thermometer which indicates the temperature on the seven segment display. It has an resolution of 0.06deg. The 1 wire temperature sensor IC from Maxim semiconductors is used as the sensor. The DS18S20 Digital Thermometer provides 9–bit centigrade temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18S20 communicates over a 1-wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of –55°C to +125°C. In this project the negative temperatures are not taken so that it will display the temperature from 0deg to 99.9deg.

Monday, November 19, 2007

Sending Data From The PC to a Microcontroller

In this article we are going to learn how to send data to a microcontroller and make the microcontroller respond to the data. For simplicity we are just going to send data to turn on and off an LED which is connected at port P2.0.

So lets start off with designing a communications protocol. From VB we will send an ASCII 255, as a synch byte, and the on/off state (0 or 1). The microcontroller will wait for two (2) bytes of data. After these two bytes of data are received, it will then either switch on/off the LED

Visual Basic at PC side
To get started open Visual Basic.
Start a new Standard EXE.
Next go to the Project | Components... menu
Check the Microsoft Comm control 6.0.
Click OK.
Next double-click on the yellow phone in the toolbar to add the MSComm control to your form.

Now add two option buttons from the tool bar name as "opton" and "optoff", change the caption to ON and OFF for both buttopns.
Now add a command button named cmdsend from the tool bar, and chage the caption to "SEND"

On To The Code
Now that the form is set up and ready to go, we need to start adding our code to the project. The user will select a pin state from option button, and then click cmdSend to send the data to the microcontroller. So first of all we need to set up the MSComm control, and select one of the pin states to start with. So lets add the following code to our form...

Private Sub Form_Load()
On Error Resume Next
'use comm port 1
MSComm1.CommPort = 1
' 9600 baud, no parity, 8 data bits, 1 stop bit
MSComm1.Settings = "9600,N,8,1"

' Disable DTR
MSComm1.DTREnable = False

'open the port
MSComm1.PortOpen = True
End Sub

Now we just need to add the code to send the data. When the user presses cmdSend, we need to do three things.

Get the pin state...
Send the data...

Now lets put it all together and send the data when we press the cmdSend button...

Private Sub cmdsend_Click()
Dim LED As Long

' Get LED State
If opton.Value = True Then
LED = 0
LED = 1
End If

' Send Out Data
MSComm1.Output = Chr$(255) & Chr$(LED)

End Sub
So we sent out the synch byte (255),followed by the LED state.

Finally we need to close the comm port when the VB project unloads so...

Private Sub Form_Unload(Cancel As Integer)
MSComm1.PortOpen = False 'Close the COMM port
End Sub

That's all at the PC side

Microcontroller Side
Program the MIcrocontroller with the following code

ORG 00H ; Reset
MOV TMOD,#20H ;enable timer1, mode 2 (auto reload)
MOV TH1,#0FDH ;9600 Baud rate
MOV SCON,#50H ;8 bit, 1 stop bit, REN enabled

HERE:JNB RI,HERE ;wait for character to come in
MOV A,SBUF ;get data in A
CJNE A,#0FFH,DOWN ;chk if the char is synch byte ie.offh or 255
;if not jump to clear RI
CLR RI ;get ready to get next byte
WAIT:JNB RI,WAIT ;wait for character to come in
MOV A,SBUF ;get data in A
CJNE A,#00H,NXT ;chk if the char is 0
CLR P2.0 ;switch on LED
SJMP DOWN ;jump to clear RI
NXT:CJNE A,#01H,DOWN ;chk if the char is 1
SETB P2.0 ;switch off LED
DOWN:CLR RI ;get ready to get next byte
SJMP HERE ;keep getting the data
Now run the VB project, select either ON or OFF, and press send. You should see the LED turn ON when you send a ON command, and turn OFF when you send a OFF command.

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Wednesday, October 31, 2007

Digital IC Tester for 74 series using 89C55 Microcontroller

The chip tester verifies the functionality and timing of a variety of 7400 series integrated circuits. Students taking Digital Logic Design Lab, Use these chips often in their laboratory. The IC to be tested should be placed on the ZIF socket and the Microcontroller prompts the user to enter the IC number of the chip to be tested. After entering it the microcontroller will check the IC as per the truth table of the IC which is stored in its ROM. It will check each aand every pin of the IC and produce the Output detaily. Like "Gate 1 is good", "Gate is Bad", "Counter 1 is Good" etcThe Block diagram of the project is given below for referenceFor IC's list that can be tested by this project Click here

Monday, September 24, 2007

Voice Ineractive System For College Automation (AT89C2051 + VB)

Now-a-days every institution needs automation. As a part of college automation, we have decided to do a project “Voice Interactive System for College Automation”. Our project allows the user to know the student’s attendance and marks quickly through the telephone line without the intention of the college authority. In the hardware side embedded system has been used. A 20 pin microcontroller 89C2051 is used because of its compatibility with our hardware. This microcontroller controls the whole hardware. Telephone line is used for communication purpose. Visual Basic has been used for software programming. Presentation in the class and outcome of the university are made reachable to the parents by our project. It will be very obliging to the parents to be acquainted with their son’s/daughter’s recital in the college.