How to make a fingerprint sensor door lock with Arduino UNO development board!

Arduino UNO development board

How to make a fingerprint sensor door lock with Arduino UNO development board!

Learn how to use the sensor module, I2C LCD, and Arduino UNO development board to make a fingerprint-controlled door lock.

In this article, I will show you how to make a smart door lock using a fingerprint sensor and Arduino UNO. The door lock will open only when the fingerprint scanned by the user matches the fingerprint recorded on the system. If the fingerprint entered is wrong, the door will remain closed.

Required hardware

● Arduino UNO development board

● Fingerprint sensor module

● I2C LCD display

● Relay module

● Door lock

● 7 to 12V power supply

● Jumper cable

Circuit diagram and description

First, connect the fingerprint sensor to the Arduino UNO development board. Please make sure that the fingerprint sensor you use can work with Arduino through serial communication.

The default pins for serial communication on Arduino UNO are pin 0 (RDX) and pin 1 (TXD) of the board, but we will use other pins for serial communication. In this article, we will use the SoftwareSerial library in the code.

The following are the connections required between the fingerprint sensor and the UNO development board:

Then connect the I2C LCD module to UNO. The connection is as follows:

Then, connect the relay module to the Arduino UNO as shown in the circuit diagram below.

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Fingerprint door lock circuit diagram.

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To control the door lock, you need a 7 to 12V battery-I used three 18650 batteries.

For more information, please refer to the following link:

3D printing

What is 3D printing?

Ordinary printers used in daily life can print computer-designed flat objects. The so-called 3D printers have basically the same working principle as ordinary printers, except that the printing materials are somewhat different. The printing materials of ordinary printers are ink and paper, while 3D printers contain metal. Different “printing materials” such as ceramics, plastics, sand, etc. are tangible raw materials. After the printer is connected to the computer, the “printing materials” can be superimposed layer by layer through the computer control, and finally the blueprint on the computer becomes In kind. In layman’s terms, a 3D printer is a device that can “print” real 3D objects, such as printing a robot, printing a toy car, printing various models, and even food. The reason why it is commonly called “printer” is based on the technical principles of ordinary printers, because the process of layered processing is very similar to inkjet printing. This printing technology is called 3D stereo printing technology.

There are many different technologies for 3D printing. Their difference lies in the way of available materials and the construction of different layers to create parts. Commonly used materials for 3D printing include nylon glass fiber, polylactic acid, ABS resin, durable nylon materials, gypsum materials, aluminum materials, titanium alloys, stainless steel, silver-plated, gold-plated, and rubber materials.

single board computer

What is a single-board computer?

A complete computer based on a single circuit board, including microprocessor, memory, Ethernet, I/O, video, and audio output. The core architecture of the design is the microprocessor. The first true single-board computer was probably the MYCRO-1, built on an Intel 8080 CPU.

A single-board computer has a configuration similar to other plug-in cards and is designed for use in the backboard. Some architectures are completely dependent on the single-board computer, such as PICMG, ISA, PCI, Compact PCI, VME, and so on. In the PC world, the intelligence and interface/control circuits are placed on inserts that have been inserted into the passive (or active) type backboard. The result is similar to a motherboard-based system, except that the baseboard determines the slot configuration. The base plate can be in a combination of slots (ISA, PCI, PCI-X, PICMG, etc.), usually with a total number of 20 or less, which means that the base plate can be installed in a 19″ rack housing or some wall-mounted compact cases.

In the single board computer is any computer need to apply the ideal solution, but the space is precious as the booth application type, single-board computer, can be used in the aircraft, and industrial machinery in the data center, many computers needs such as Internet service providers, many single board computer can be installed to a server rack system.

The greatest advantage of a single board computer is the small space requirements and extremely low power consumption. In addition, a single board computer can be manufactured according to strict cost-saving specifications in a place where the computer does not have to be presented such as sound, environment, and audio jacking can simply be ignored by the design.

Learn ARM development

Learn the meaning of ARM development

As long as you learn one kind of processor, there are many ARM core processors for you to use. From the above, you can see that many companies provide chips based on this core, such as the world-famous INTEL, TI, MOTOROLA, and other companies. ARM chip. In the embedded field, 8-bit processors are no longer competent for some complex applications, such as GUI, TCP/IP, FILESYSTEM, etc., and ARM chips are very suitable for these occasions with their powerful processing capabilities and extremely low power consumption. Therefore, more and more companies are considering the use of ARM processors when selecting products. From this perspective, for college students, if you have mastered ARM development technology, it is also useful for finding a good job. Very advantageous.

In addition, the ARM craze has been launched in China, as can be seen from the indispensable ARM forums in various electronic forums, so you don’t have to worry about having problems and no place to communicate.

How to start learning ARM

ARM learning can be divided into COS development and design based on ARM core and development and application based on ARM SOC. Since the webmaster is doing ARM SOC applications, I will discuss the application development of ARM chips, not about ARM chip design.

I think we should first understand the ARM core and don’t need to go too deep, after all, it is not engaged in chip design. Then it is more important to get familiar with the ARM instruction set. Although C is used to develop programs nowadays, many initialization programs are written in assembly. Then, to master the use of an integrated development environment (IDE), be sure to use it proficiently. It is recommended to use IAR EWARM and ADS1.2. The manual is available in the installation directory after the IDE installation is complete.

Then buy an ARM learning board according to your learning direction and interest (if you are familiar with the hardware, general development boards are now provided with schematic diagrams for free, you can make a version according to the schematic diagram of the development board), for example, if you want to do some networking For programming, you can choose S3C4510B. This chip with a 100M network (many ARM processors can also expand a network port, usually 10M, such as RTL8019AS and CS8900, etc.) The chip price is less than 50 yuan, which is very suitable. If you want to make a PDA, you can choose S3C44B0X, S3C2410, and other chips with LCD interfaces.

General development boards will have some simple routines. Through these routines, you will gradually become familiar with the steps of ARM programming and the use of IDE. During this process, you will gradually eliminate the mystery of ARM. Finally, when you are more proficient, ARM is A tool under your control, a cheap and powerful tool.

embedded development characteristics

MCU, ARM, FPGA, embedded development characteristics

Today, I would like to share with you my views on the characteristics of microcontroller, ARM, FPGA, and embedded development. If there is any omission, I hope you will leave a message to remind me.

1. Features of SCM:

(1) Restricted by the degree of integration, the on-chip memory capacity is small, generally the internal ROM: less than 8KB;

(2) Internal RAM: less than 256KB.

(3) High reliability

(4) easy to extend

(5) Strong control function

(6) Easy to develop

2. Features of ARM:

(1, comes with cheap program memory (FLASH) and non-volatile data memory (EEPROM). These memories can be written repeatedly, which makes the program development experiment more convenient and work more reliable.

(2) High speed, low power consumption. The working speed of the AVR microcontroller is 30-40 times that of the M51 microcontroller under the condition of the same external crystal vibration. And add the sleep function and CMOS technology, so that its power consumption is much lower than the M51 microcontroller.

(3) Industrial grade products. With large current output can be directly driven ××× and relay, a watchdog timer, to prevent the program to fly, thus improving the anti-interference ability of the product.

(4) super function simplified instruction, with 32 general working registers, equivalent to M51 microcontroller in 32 accumulators! The bottleneck effect of the single accumulator is overcome.

(5) The program is easy to download. AVR microcontroller can be downloaded in parallel or serially, without an expensive programmer. In addition, it can be downloaded online! That is to say, you can modify and burn the program directly on the circuit board.

(6) With analog comparator, pulse width modulator, analog-to-digital conversion functions. It makes analog signal processing in industrial control more simple and convenient.

(7, parallel port, timing counter, interrupt system and other important resources of the SCM internal functions have been greatly improved so that it is more suitable for the real-time control of the industrial production process.

(8 )its clock frequency can be connected to the external or use the MCU internal oscillator, its frequency can be set in 1MHz-8MHZ, making the hardware development and production more concise.

(9) Powerful communication function, built-in synchronous serial interface SPI, universal serial interface UART, two-wire serial bus interface TWI(I2C), make network control, data transmission more convenient.

(10) Super secret function, the application can use multiple protection lock functions. It can quickly complete the commercialization of manufacturers’ products at low prices and so on. In addition to the above features, “zero peripheral” is also an important feature of the AVR embedded microcontroller. Because the chip has built-in program memory, crystal oscillator, and increased online assembly function.

So AVR microcontroller chip connected to the DC power supply, download a program that can work independently. No additional external equipment, no need to use expensive programmers and emulation devices. This has brought us convenient conditions for learning and development.

3. FPGA features:

(1) The design of ASIC circuit using FPGA (special-purpose integrated circuit), users do not need to chip production, can get the common chip.

(2)FPGA can be used as a pilot sample of other full-customized or semi-customized ASIC circuits.

(3) There are abundant triggers and I/O pins in FPGA.

(4)FPGA is one of the devices with the shortest design cycle, the lowest development cost, and the lowest risk in the ASIC circuit.

(5)FPGA adopts high-speed CMOS technology, low power consumption, and can be compatible with CMOS and TTL levels.

It can be said that the FPGA chip is one of the best choices for the small-batch system to improve system integration and reliability.

FPGA is stored in the chip RAM program to set its working state, so it is necessary to work on the chip RAM programming. Users can use different programming methods according to different configuration modes.

When power-on, the FPGA chip reads the data from EPROM into the on-chip programming RAM. After the configuration is completed, the FPGA enters the working state. After power down, the FPGA recovers into a white chip, and the internal logic relationship disappears. Therefore, the FPGA can be used repeatedly. FPGA programming does not need a special FPGA programmer, just use the general EPROM, PROM programmer can. When you need to modify the FPGA function, just change an EPROM. In this way, the same FPGA, different programming data, can produce different circuit functions. Therefore, the use of FPGA is very flexible.

3. Features of embedded system

The system kernel is small

Because the embedded system is generally used in small electronic devices, the system resources are relatively limited, so the kernel is much smaller than the traditional operating system. For example, in the ENEA OSE distributed system, the kernel is only 5K, and the Windows kernel? There’s no comparison.

② strong specificity

Embedded system is highly personalized, in which the combination of a software system and hardware is very close, generally for the hardware of the system for transplantation, even in the same brand, the same series of products also need to be modified according to the changes and changes of the system hardware. At the same time for different tasks, often need to make major changes to the system, the compilation and download of the program should be combined with the system, this kind of modification and the general software “upgrade” is completely two concepts.

③ system simplification

Generally, there is no obvious distinction between system software and application software in embedded systems, so it is not required to be too complicated in functional design and implementation. This helps to control the cost of the system on the one hand, and also helps to achieve system security on the other.

④ High real-time system software (OS) is the basic requirement of embedded software. And the software requires solid-state storage to increase speed; Software code requires high quality and reliability.

(5) If embedded software development wants to move towards standardization, it must use a multitasking operating system

Applications of embedded systems can run directly on a chip without an operating system. However, to reasonably schedule multiple tasks, utilize System resources, System functions and interface with expert library functions, users must select the RTOS (Real-time Operating System) development platform by themselves, to ensure the real-time performance and reliability of program execution, reduce development time and ensure software quality.

⑥ Embedded system development needs development tools and environment.

Due to its itself cannot develop bootstrap, even after the completion of the design of the user is usually can’t modify the program function, must be to develop a set of development tools and environment, these tools and the environment is generally based on general computer soft hard piece of equipment and a variety of logic analyzer, mixed-signal oscilloscope, etc. Development often has the concept of host and target machine, the host is used for the development of the program, the target machine is the final execution machine, development needs to be combined alternately.

cheap ARM computers

Single-board computers are popular. What can cheap ARM computers do?

In recent years, single-board computers similar to the Raspberry Pi can be said to be very popular. The biggest feature of this type of product is its small size and simple product structure. It is developed based on the ARM architecture, which means that it does not natively support what everyone is familiar with. X86 architecture applications. Not long ago, Hardkernel launched its new generation single-board computer ODROID XU4. The price of only $75 makes this little guy quite cost-effective, but can this kind of cheap ARM-based mini-computer replace traditional PCs?

From the point of view of parameters, the overall performance of ODROID XU4 is the same as that of current mid-range smartphones. It is equipped with a Samsung Exynos 5422 octa-core processor clocked at 2GHz and 2GB RAM. The motherboard has an Ethernet interface and 2 USBs. 3.0 interface, 1 USB 2.0 interface, 1 HDMI video interface, and 1 GPIO interface, and even a CPU cooling fan can be installed, and the memory chip needs to be purchased separately. Due to the ARM architecture, ODROID XU4 can run operating systems designed based on the ARM architecture, including Debian, Ubuntu, and Android.

Due to the special attributes of the ARM architecture, the palm-sized ODROID XU4 does not run standard x86 applications, such as Office, Acrobat, and Spotify, like mini PCs and barebones. Therefore, it is difficult for many ordinary users to adapt. Fortunately, there are also many software versions of Linux that can run on ARM-based devices.

If the software you want to use only exists on the PC platform of the x86 architecture, then there is also an emulator like Exagear Desktop to choose from, but the emulator means lower operating efficiency, and the effect of running Office is not bad, but if you run 3D For large-scale applications such as games or Photoshop, cheap ARM-based computers are still a little weak. After all, it is indeed difficult for the Galaxy S5 to run LOL smoothly.

Since the hardware performance and software environment are not as good as x86 architecture traditional PCs, who are these ARM architecture single-board computers suitable for? The first is those developers with special purposes, such as various IoT smart devices. Of course, if you have strong hands-on ability, you can also convert it into a TV box or even a cloud server.

Best Single Board Computers

2021 Best Single-Board Computers for Every Use and Budget

It’s 2021, you know computers, notebooks, etc., but have you heard of single-board computers? This is a very interesting thing, more and more developers and smart home products are using it.

Compared with computers and notebooks, Maybe some people have heard of single-board computers, but they don’t know the specifics.

What is a single-board computer?

As the name suggests, a single-board computer is a device with all of its components such as RAM, a GPU, and CPU baked-in. Compare that to a traditional desktop PC where the motherboard comes sans memory and processors. Furthermore, most SBCs feature smaller footprints than their desktop counterparts. Still, there’s variation. Whereas some maker boards arrive in credit card-sized form factors, others are decidedly larger.

What can You do With a Single Board Computer?

The first is those developers with special purposes, such as various IoT smart devices. Of course, if you have strong hands-on ability, you can also convert it into a TV box or even a cloud server.

What factors need to be considered when using a single-board computer?

When selecting the best top single-board computer for your needs, you’ll want to consider your priorities. Cost is a factor, and size matters, too.

Of course, what you plan to use your maker board for is essential. For basic tasks that don’t require much computing power, almost any board will do. But you might need a more capable device for multi-tasking or advanced processing.