A lock is a very essential part of any house or apartment or office. A man can go away from his house peacefully after locking the house. Otherwise, there is a chance of stealing. At this time the mechanical locks are used which have levers and can be unlocked by key. Each lock has a different key. But after getting old, these locks can be damaged by rust. So the owner has to buy another one.
Nowadays there is an electronic number lock introduced in the market which can be easily operated by passwords. In this project, we are going to build an electronic number lock system. We show here how an electronic number lock works with a relay and switches. In the place of load, you can connect door motor, locker locks, and any type of electric locks.
Principle Behind Electronic Number Lock System
The electronic number lock is described here as an electronic unit operated with a mechanical number lock. Three selected numbers are operated one by one so the relay connected to the load can be operated. When the code has been entered, the load connected to the relay gets the power and starts working.
- EC103D SCR (x3)
- 1KΩ Resistor (x3)
- 10KΩ Resistor
- 4.7KΩ Resistor
- BC148 Transistor
- SL100 Transistor
- 12V Relay
- Push Switch (x11)
- 12V Power Supply
The 8th Anniversary of PCBWay Has Begun! Enjoy Heavy Discount
PCBWay has come with an amazing discount. PCBWay is here to celebrate its 8th Anniversary and offer free coupons worth $200, Anniversary sales and lucky draws that are available while supplies last. So please hurry up. You can get upto 92% off on PCB prototypes and 65% off on PCB assembly and 30% off on FPC/Rigid-Flex during the anniversary sale. Log in with your account and claim exciting coupon codes and you may end up as the lucky winner of one of two Raspberry Pi 4 Model B boards.
This giveaway is especially for those who had ever purchased their products before and share with them the joys of DIY electronics. During the promotion time, each customer (who had made one or more orders) will have two chances to draw the lucy draw and one extra chance will be given if you place an order during the promotion time.
So just go to their website and grab these offers as fast as possible.
Order PCB From PCBWay
There are so many forums or communities for electronics online in today’s technical world, and one of the famous ones for PCB manufacturing is the PCBWay. PCBWay is a place that brings manufacturers and customers together. They have more than a decade of experience in this field of fabrication, prototyping and assembling PCBs. PCBWay has proved its focus on its customers’ needs in terms of cost-effectiveness, delivery, and quality.
How PCB Manufacturing Process Done in PCBWay
Standard quality for any product needs to be maintained using some parameters. PCBWay gives that opportunity through quality control in designing and manufacturing. At first, they ensure the accuracy, clarity, and validity of the PCB files that we sent to them.
Then all the boards will go through the most stringent tests other than the basic visual check. They adopt most of the testing and inspecting equipment used in the industry, such as Flying Probe Tester, X-Ray Inspection Machine, and Automated Optical Inspection (AOI) Machine. PCBWay are having 50+ new engineers on the daily basis around the world using PCBs for their work, who trust for their reliable quality. They produce high-quality pink, orange, grey, and even transparent solder mask. Moreover, according to people’s needs, they can also provide Black core PCB. Check it out for a High-Quality PCB solder mask. There are some pictures below of the new colours of solder musks.
Features of PCBWay
PCB Prototyping & Manufacturing: PCBWay produces FR-4 and Aluminum boards and advanced PCBs like Rogers, HDI, Flexible and Rigid-Flex boards, at a very reasonable price. Just check this Instant Quote to order premium PCBs for your hobby projects.
PCB Assembly: It not only offers PCB Prototyping but also offers PCB Assembly service. You can order a full PCB board with attached components by uploading your file. SMT & THT assembly starts from only 30$ including free stencil and worldwide shipping. The components can be sourced and provided by PCBWay, or by clients themselves.
Open Source Community: It not only offers PCB Prototype & Assembly service but also gives opportunities to students for sponsorships. I think this is so great. They feature their projects on the website also.
3D Printing & CNC: It also produces Rapid Prototyping like 3D printing, CNC Machining, Sheet Metal Fabrication, and Injection Molding. The quality of the product is too premium and reliable. And also the best part is that you will receive your order within a minimum of 3 days.
PCBWay Store: More boutique gift modules are waiting for you to discover, giving your creativity wings. You can order all types of electronic equipment, components and many more with exciting offers. Go with the link and buy your needs, PCBWay Store.
Services: PCBWay offers great servicing of their products. It takes only 3 to 15 days according to courier service to deliver your products. Also, it has a live support facility. Whenever you have any problems, you can always reach a live customer service person to respond to your emails or messages. They have the “Return and Refund” principle, for every unusable board caused by PCBWay, they will rebuild and refund the order soon.
Guide for Ordering PCB from PCBWay
Block Diagram of Electronic Number Lock System
Working Principle of Electronic Number Lock System
The working principle is so simple because there are very few components are used in this project. Here three switching circuits are used with SCR. Each switch can be ON one after another. Each switching circuit consists of push buttons called the ‘number’. The other switches are connected to the ‘wrong use of the system’ circuit. Any three of them can be selected as shown in the circuit diagram.
By entering the correct three switches the circuit will turn on, otherwise, the circuit remains turn off. There are two conditions to make the system turns off. Firstly, when the positive voltage is switched off, the SCR is turned off. Secondly, when the gate has a high negative current the SCR remains turned off.
In this circuit, three SCRs are connected in series. The anode and cathode of the SCRs are connected to the negative by 1KΩ resistance. This resistance works as a load for SCR1 and SCR2 respectively. By these resistors, a very small amount of current can pass.
SCR3 is connected to the base of the BC148 transistor in series with 10KΩ resistance. The collector and emitter of the BC148 transistor are connected to the collector and base of the SL100 PNP transistor respectively. The 12-volt relay is connected between the positive and collector terminal of SL100. The emitter of SL100 is connected to the ground.
Three switches S1, S2 and S3 are connected to the gate terminal of SCR1, SCR2 and SCR3 respectively. The other switches are connected between the SCR’s gate and negative terminal with 100Ω resistance. When S1 is pressed, the SCR1 gate terminal gets the positive voltage through resistor R1 and turns on. When S2 is pressed, the SCR2‘s gate gets the positive voltage through the SCR1 cathode and then SCR2 turns on.
At last, when S3 is on, the SCR3‘s gate terminal gets positive voltage and SCR3 turns on. The cathode of SCR3 is connected to the base of T1 which gets positive voltage. So T1 and T2 are also turned on at the same time. The T2 activate R1 and the relay starts to conduct.
Now the condition is what will happen if the wrong switch is pressed. If any wrong switch is pressed the SCR1 gets more negative current through R2. So SCR1 turned off. The SCR2 and SCR3 were also turned off because of their anode voltage are zero.