Door Ajar Alert - Have you ever accidentally left your front door ajar and had a pet or your little kid escape? Here is a smart solution to this problem. This circuit alerts you every...__ Electronics Projects for You
Door Alarm - Hangs up on the door-handle; Beeps when someone touches the door-handle from outside __ Contact Flavio Dellepiane, fladello @ tin.it
Door/window sensor resists tampering - 01/21/99 EDN Design Ideas: The simple, inexpensive circuit in Figure 1 detects a failure (or deliberate tampering] on lines connected to normally closed switch sensors. For example, common door interlocks and door/window sensors consist of normally open or normally closed magnetic reed switches. Depending Page includes several designs. Scroll to find this one __ Circuit Design by Paul Nocella, Q Research, Brookline, NH
Doorbell with Security Feature - This doorbell system works such that when someone presses your calling bell switch during the night, not only the bell rings but the bulb connected to it also glows. in order...__ Electronics Projects for You
Doorbell-Controlled Porchlight - This add-on circuit automatically turns on your porchlight when your doorbell rings, so you can see the person ringing the doorbell at the doorstep. This also helps to guard against burglars, ...__ Electronics Projects for You
Doorbell-Controlled Security Switch - One way to check whether anybody is at home is to ring the doorbell. Burglars too use this very technique. The circuit described here comes handy in such a situation. it...__ Electronics Projects for You
Doorbell-Cum-Visitor Indicator - This doorbell circuit can also give identification of the visitor to your home in your absence. When you’re home, you can use it simply as a normal doorbell. The circuit (see Fig....__ Electronics Projects for You
Driveway Alarm - You can install this system in the driveway itself to detect intrusion by a vehicle, person or large animal. it sounds an alarm when any intrusion takes place. As shown in Fig....__ Electronics Projects for You
Economical Pump Controller - The automatic pump controller eliminates the need for any manual switching of pumps installed for the purpose of pumping water from a reservoir to an overhead tank (refer Fig.1). it automatically...__ Electronics Projects for You
Electric Field Disturbance Monitor-Alarm Discriminator + Battery Monitor - This schematic is the alarm discriminator plus the batterry monitor of my "Electric Field Disturbance Monitor". The system can detect human and animal motion by the electric fields they disturb. . . Circuit by David A. Johnson P.E.-March, 2002
Electric Field Disturbance Monitor-Front End + Power Supply Circuit - This schematic is the power supply and front-end sections of my field monitor, "Electric Field Disturbance Monitor". The system can detect human and animal motion by the electric fields they disturb. . . Circuit by David Johnson P.E.-March, 2002
Electronic Bicycle Lock - The electronic bicycle lock described here is a worthwhile alternative for bicycle owners who want to make their bicycles 'intelligent' at reasonable cost. One of the benefits of building it yourself...__ Electronics Projects for You
Electronic card-lock system - This is a circuit for a phototransistor detector based lock system. The system takes input in the form of punched cards that may have holes in any location corresponding to photo transistors. When a correct match is found in the lock depending upon the combination of the holes, a relay is driven and a tone is generated. __ Electronics Projects for You
Electronic Combination Lock - This 7-digit combination lock can be easily hard-wired for any combination that you choose. The circuit uses a 4-bit, divide-by-8 Johnson counter (IC 1) , ten pushbutton switches and npn transistor T1. At power-‘on, ’...__ Electronics Projects for You
Electronic combination lock based on PIC - This is my electronic combination lock to use with an outdoor gate. The functionality is implemented in software. it turns on a relay (usually to open a door) for a few seconds. Uses a PIC 16F84A. __ Designed by Peter Jakab
Electronic Combination Lock with AVR - CodeLock AVR electronic combination lock is realised with Atmel AVR microcontroller AT89C2051 or AT90S2313 or ATtiny2313 or ATtiny45. Program in hex code is 2 kB long. One user code (Ver.1) is consisted of 1 to 8 digits. One user code (Ver.2.1, 2.2, 2.3) is consisted of 1 to 4 digits. if you buy the chip (Ver.2.1, 2.2, 2.3) than you can enter 1 or 8 user codes that are consisted of 1 to 9 digits.
Electronic door codelock PIC16F84 - This is my electronic combination lock to use with an outdoor gate. The functionality is implemented in software. it turns on a relay (usually to open a door) for a few seconds if someone enters the valid code. Alternatively, it works as an ON/OFF switch, which toggles the relay each time the code is entered __ Designed by Peter Jakab
Electronic Door Key - This circuit is basically a short-range, infrared remote-controlled electromagnetic relay driver. it can be used to control door motors or solenoid-based locks using a compact and handy remote handset. The circuit comprises...__ Electronics Projects for You
Electronic Door Lock - Home burglary incidents are on the rise. Homes without proper security measures in place are particularly more vulnerable. But, it is easy to avoid home break-ins by using a simple solution...__ Electronics Projects for You
Electronic Eye Security System - The electronic eye security systems available in the market are expensive, and programming is very difficult for a microcontroller based system. Here is a simple and inexpensive electronic eye security system...__ Electronics Projects for You
Electronic Keypad - The IC is a quad 2 input "AND" gate, a CMOS
4081. These gates only produce a HiGH output, when BOTH the inputs are HiGH. When the key wired to 'E' is pressed, current through R1 and D1 switchs Q5 on. The relay energises; and Q5 is 'latched on' by R8. Thus, the Alarm is set by pressing a single key, say one of the two non-numeric symbols __ Designed by Andy Collison
Electronic Lock - 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 __ Designed by Bill Bowden
Electronic Lock - This is a simple but efficient Electronic lock. This lock can be used to protect any electronic systems from unauthorized usage. To get access the uses needs to know 8 digit pass-code or password. When the user enters correct 8 digit password followed by "Enter" button, it activates the relay allowing access to the system controlled by relay. if the 8 digit pass-code is incorrect, after pressing "Enter" button, the circuits reset's itself without turning the relay on. __ ` Sigmatone
Electronic Locker - This circuit is an Electronic Locker. it is controlled by a switches combination (by a code). There is a switch matrix on the door of the locker. This one is a unit of switches connected into 4 arranged of 4 columns for a total of eight terminals__
Electronic Police Siren - The sound produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors is discharged and both transistors. __ Designed by Ron J.
Electronic Safety Lock Based on Attiny26 - This safety-lock can be work with up to 8 different telecards (empty or not) as access keys. Each telecard can be registered or unregistered from the system, by press the corresponding button. __ Designed by © Vassilis Serasidis
Electronic safety-lock with telecard as key - This safety-lock circuit use the new Atmel AVR microcontroller series, the ATtiny26. This micros (and new ATmega8 , ATmega16 etc) are powerful microcontrollers with new features like internal RC calibrated oscillator for 1, 2, 4 __ Designed by Vassilis Serasidis
Electronics Card-Lock System - The circuit presented here can be used as a lock for important electronic/electrical appliances. When card is inserted inside its mechanism, depending upon the position of punched hole on the card, a...__ Electronics Projects for You
Emergency Light - A simple circuit that activates a light when the power is out. A version with a lightbulb and another with white LED light included. __ Designed by Jose Pino
Emergency Light & Alarm - Powered by two AA Ni-CD batteries; Four switchable options __ Contact Flavio Dellepiane, fladello @ tin.it
Emergency Photo Lamp - This emergency light can be powered either by a rechargeable battery (like 3.6V Ni-Cd) or a non-rechargeable battery (3.0V CR2032). The white LED (LED1) glows automatically when the power fails and...__ Electronics Projects for You
Emergency Power - This unit was constructed in a plastic 4-outlet juction box ($5 from Home Depot). The front panel is cut from 60-thou Lexan, and a scrapped Pep-Boys battery charger provided the transformer. The PIC 16F870 keeps track of battery voltage as well as both charging and discharging currents. __ Designed by Luhan Monat-Mesa Arizona
Emergency Siren Simulator - This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Emergency-Cum-Ultraviolet Light - This circuit serves both as an emergency light (using a 6W fluorescent tube) and an ultraviolet light (using a 6W ultraviolet tube). Step-down transformer X1, diodes D1 through D4, capacitor C1 and...__ Electronics Projects for You
Enhanced 5 Digit Alarm Keypad - This is an enhanced 5 digit keypad which may be used with the Modular Alarm System. This switch will suit the Modular Burglar Alarm circuit. However, it also has other applications. The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. Choose the five keys __ Designed by Andy Collison
Enhanced Shed / Garage Alarm - Battery-Powered Alarm Circuits: This is an enhanced version of the simple Garage/Shed Alarm. The Entry and Exit delays have been increased to about 30-seconds - and I'veadded a timed Siren cut-off and automatic Reset. I'vealso replaced the LED with an entry Buzzer. These enhancements mean that the new version will have a much wider application. __ Designed by Ron J.
Estimating available applicaiton power for Power-over-Ethernet applications - Many existing Ethernet devices are being converted from wall-adapter power sources to utilize the newly released iEEE 802.3af Power-over-Ethernet (PoE) standard. Powersystem efficiency formerly was not much of an issue with a wall adapter—but PoE changes that. __ Designed by Texas Instruments App Notes, 25-Feb-05
Ethernet based Security System - The need for Security systems have rapidly grown from being specialized for high-risk areas (like banks, companies , governmental institutions) , to be available and demanded rapidly by the average public. in the last ten years, small businesses have rapidly grown and expanded and the need of reliable, cheap and effective security system is becoming a must , not only for the business owners , but also at homes __ Contact IQ Technologies
Everything-that-moves alarm - A crucial failing of proximity detectors is their unreliable and tricky nature. This is where they are used to detect humans, not to speak of smaller living beings. One common approach is to detect __ Designed by © Rev. Thomas Scarborough
Expandable Multi-Zone Modular Burglar Alarm - Multi-Zone Burglar Alarm Circuits: This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. it has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. By using the Expansion Modules, you can add as many zones as you require; some or all of which may be the inertia (shock) sensor type. __ Designed by Ron J.
Expandable Transistor Based Burglar Alarm - Multi-Zone Burglar Alarm Circuits: This transistor based alarm features automatic Exit and Entry delays - together with a timed Bell Cut-off and system Reset. Along with the Exit/Entry zone - the basic alarm board has one instant Zone. This will be adequate in many situations. However - the modular design means that it's easy to add as many zones as you like to the system. Details of a Four-Zone expansion module are provided. __ Designed by Ron J.