Animation of how power lock system works (simple relay operation) Power door locks (also known as electric door locks or central locking) allow the driver or front passenger to simultaneously lock or unlock all the doors of an automobile or truck, by pressing a button or flipping a switch. Power door locks were introduced on the luxury Scripps-Booth in 1914, but were not common on luxury cars until Packard reintroduced them in 1956. Nearly every car model today offers this feature as at least optional equipment. Early systems locked and unlocked only the car doors. Many cars today also feature systems which can unlock such things as the luggage compartment or fuel filler cap door. It is also common on modern cars for the locks to activate automatically when the car is put into gear or reaches a certain speed. See also: Remote keyless system Pressing a button on the key unlocks all of the car doors. Another button locks the car. In 1980, Ford Motor Company introduced an external keypad-type keyless entry system, wherein the driver entered a numeric combination —either pre-programmed at the factory or one programmed by the owner— to unlock the car without the key.
Early- to mid-1980s Nissan Maximas could also be installed with a keypad, which would also retract the windows and moonroof once the car was successfully unlocked by pushing a specific button on the keypad. During the 1990s the Subaru Legacy could also be opened by pulling the drivers external door handle a specific number of times to enter a passcode number that would unlock the driver's door only. Today, many cars with power door locks also have a radio frequency remote keyless system, which allows a person to press a button on a remote control key fob, the first being available on the French made Renault Fuego in 1982.[1] Currently, many luxury makers also allow the windows to be opened or closed by pressing and holding a button on the remote control key fob, or by inserting the ignition key and holding it in the lock or unlock position in the external driver's door lock. The remote locking system confirms successful locking and unlocking through either a light or a horn signal, and usually offers an option to switch easily between these two variants.
Both provide almost the same functionality, though light signals are more discreet while horn signals might create a nuisance in residential neighborhoods and other busy parking areas (e.g. short-term parking lots). Some manufacturers offer the ability to adjust the horn signal volume. Other cars have a proximity system that is triggered if a keylike transducer (Advanced Key or handsfree) is within a certain distance of the car. Power Management IC (PMIC) MOSFET and IGBT Gate Drivers Simple Code Lock Circuit This simple code lock circuit described here is of an electronic combination lock for daily use. It responds only to the roght sequence of four digits that are keyed in remotely. If a wrong key is touched, it resets the lock. The lock code can be set by connectiong the line wires to the pads A, B, C and D in the figure. For example, if the code is 1756, connect line 1 to A, line 7 to B, line 5 to C, line 6 to D and rest of the lines-2,3,4,8 and 9 to the reset pad as shown by dotted lines in the schematic.
Schematic of the code lock circuit The code lock circuit is built around two CD4013 dual-D flip-flop ICs. The clock pins of the four flip-flops are connected to A, B, C and D pads. The correct code sequence for energisation of relay RL1 is realised by clocking points A, B, C and D in that order. The five remaining switches are connected to reset pad which resets all the flip-flops. Touching the key pad switch A/B/C/D briefly pulls the clock input pin high and the state of flip-flop is altered. The Q output pin of each flip-flop is wired to D input pin of the next flip-flop while D pin of the first flip-flop is grounded. If correct clocking sequence is followed then low level appears at Q2 output of IC2 which energises the relay through relay driver transistor T1. The reset keys are wired to set pins 6 to 8 of each IC. (Power-on-reset capacitor C1 has been added at EFY during testing as the state of Q output is indeterminate during switching on operation.) This simple code lock circuit can be usefully employed in cars so that the car can start only when the correct code sequence is keyed in via the key pad.
The code lock design can also be used in various othee application. 2-Year Camera Protection Plan New (3) from $12.99 + $0.99 shipping Sold by Docooler and Fulfilled by Amazon. Docooler RFID Proximity Door Entry Access Control System + 10 Key Fobs (Style 1)DetailsGeneric K80 Door Access System Electric Power Supply Control DC, 12V 3A/AC 110V FREE Shipping on orders over . DetailsAGPtek 60kg 130LBs Holding Force Electric Magnetic Lock for Door Access Control System Electromagnet… 1.2 x 5.2 x 5.4 inches Door Controller Size: 11.7 x 11.7 x 2.1 cm Traditional appearance with useful function and high quality Professional design, great for home and office high security, come with user manual Operating voltage: DC 12V Static current: <0.6A Card quantity: 800pcs/800pass word Maximum card-sensing distance: 10cm-20cm RF card type: EM or EM compatible card 3 options to open your door (admin user selectable): Card (Key Tag) & Password Card (Key Tag) Only Password Only Package Content: 1 x RFID Access Control Panel 10 x RFID Key-fobs 1 x User instruction 1 x Bag of accessories plastic insert for fixing and screws Product Information Product Dimensions 5.4 x 5.2 x 1.2 inches Item Weight 8 ounces Shipping Weight 8 ounces (View shipping rates and policies) ASIN B009NQUPZW Customer Reviews 3.6 out of 5 stars Best Sellers Rank #13 in Industrial & Scientific > Commercial Door Products > Commercial