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What i am making here is a USB lock with smartcard key. The idea is that a phonecard reader made with a PIC micro will be able to store a number of different phonecards into memory. Whenever one of these cards is inserted into the slot, it will activate a 4-ports USB On/Off switch. If the card is removed, the USB ports will be de-activated. [ ]

This is a Simple project of  Electronic Lock Circuit diagram. There are six (or more) push switches. To 'unlock' you must press all the correct ones at the same time, but not press any of the cancel switches. Pressing just one cancel switch will prevent the circuit unlocking. When the circuit unlocks it actually just turns on an LED for about one second, but it is intended to be adapted to turn on a relay which could be used to switch on another circuit. Please Note: This circuit just turns on an LED for about one second when the correct switches are pressed. It does not actually lock or unlock anything! Simple Electronic Lock Circuit diagram :   Simple Electronic Lock Circuit Diagram Stripboard Layout : Parts : resistors: 470, 100k ×2, 1M capacitors: 0.1μF, 1μF 16V radial on/off switch push-switch ×6 (or more) stripboard 12 rows × 25 holes red LED 555 timer IC 8-pin DIL socket for IC battery clip for 9V PP3   A kit for this project is available from RSH Electronics: www....

This is simple project of Electronic Door Lock Circuit Diagram. Its easy to build and straight forward. This electronic door lock has a remarkable conception because it uses only one active component. How does it work? Electronic Door Lock Circuit Diagram To put the relay in tension the 4 buttons S1 – S4 must be pressed. If anyone of the 4 butoons S5 – S8 are pushed the relay doesn’t switch. The supply voltage must be equal to the working voltage of the relay. One transistor like BD135 can switch up to 0.5A, at the same time 2N2222 can do only 0.2A. Sourced By: Streanpowers

This is Simple Code Lock circuit. This circuit will turn on a relay when the 8-way DIP switches receives the correct code. Here is the schematic diagram of the circuit: There are two different types of DIP, they are piano-key DIP sw and 8-way DIP sw. This circuit will not draw the current if the switch is kept off. This circuit can give 256 different combination because the combination is in binary. So it would be very difficult for a burglar to keep up with the settings of the switches

This code lock is useful for appliances requiring exclusive or authorised use by those who know the preset code. If desired, the code can be changed. The circuit doesn’t require additional AND or NOT gate operations at the outputs. It uses two pairs of 4-way DIP switches. The code is set using DIP switches DIP3 and DIP4. Then these two switches are hidden inside the assembly. With DIP3 and DIP4, up to 256 code combinations are possible. The unlocking code is set by the user using DIP switches DIP1 and DIP2, which is compared with the preset code entered earlier via DIP3 and DIP4. If the two codes match, transistor T1 conducts. 8-Digit Code Lock for Appliance Switching Circuit Diagram   The codes are compared using two cascaded 4-bit magnitude comparator Ics (IC1 and IC2). If the input nibble present at DIP1 matches with preset DIP3 nibble, output pin 6 of IC1 (connected to input pin 3 of IC2) goes high. Now if nibble present at DIP2 matches with the preset nibble at DIP4, pin 6 of ...

Download PDF version of this page  There are six (or more) push switches. To 'unlock' you must press all the correct ones at the same time, but  not  press any of the cancel switches. Pressing just one cancel switch will prevent the circuit unlocking. When the circuit unlocks it actually just turns on an LED for about one second, but it is intended to be adapted to turn on a relay which could be used to switch on another circuit. Please Note:  This circuit just turns on an LED for about one second when the correct switches are pressed. It does not actually lock or unlock anything! This project uses a 555 monostable circuit. Parts Required resistors: 470, 100k ×2, 1M capacitors: 0.1µF, 1µF 16V radial red LED 555 timer IC 8-pin DIL socket for IC on/off switch push-switch ×6 (or more) battery clip for 9V PP3 stripboard 12 rows × 25 holes Stripboard Layout Circuit diagram

Build a Simple Digital Electronic Lock Circuit Diagram . This is a Build a Simple Digital Electronic Lock Circuit Diagram . The digital lock shown below uses 4 common logic ICs to allow controlling a relay by entering a 4 digit number on a keypad. The first 4 outputs from the CD4017 decade counter (pins 3,2,4,7) are gated together with 4 digits from a keypad so that as the keys are depressed in the correct order, the counter will advance. Simple Digital Electronic Lock Circuit Diagram As each correct key is pressed, a low level appears at the output of the dual NAND gate producing a high level at the output of the 8 input NAND at pin 13. The momentary high level from pin 13 activates a one shot circuit which applies an approximate 80 millisecond positive going pulse to the clock line (pin 14) of the decade counter which advances it one count on the rising edge. A second monostable, one shot circuit is used to generate an approximate 40 millisecond positive going pulse which is applied...

Its easy to build and straight forward. This electronic door lock has a remarkable conception because it uses only one active component. How does it work? Electronic Door Lock Circuit Diagram To put the relay in tension the 4 buttons S1 – S4 must be pressed. If anyone of the 4 butoons S5 – S8 are pushed the relay doesn’t switch. The supply voltage must be equal to the working voltage of the relay. One transistor like BD135 can switch up to 0.5A, at the same time 2N2222 can do only 0.2A.