DIY electronic RFID Door Lock with Battery Backup

Mainboard

Elmue build a RFID electronic door lock using PN532 Controller, Vehicle Battery and Teensy 3.2 board.

The advantage of an electronic door lock is that the above security issues do not apply.
It is much better to have a safe door lock which prevents that the thief can enter than to have an alarm system which makes noise when the thief is already in. Until the police arrives he will be gone and probably some precious things will be missing. Secure locks are always better than alarm systems or cameras.

DIY electronic RFID Door Lock with Battery Backup – [Link]

RELATED POSTS

Reverse engineering the popular 555 timer chip (CMOS version)

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Ken Shirriff reverse engineer the CMOS version of 555 timer IC and explains how it works.

This article explains how the LMC555 timer chip works, from the tiny transistors and resistors on the silicon chip, to the functional units such as comparators and current mirrors that make it work. The popular 555 timer integrated circuit is said to be the world’s best-selling integrated circuit with billions sold since it was designed in 1970 by analog IC wizard Hans Camenzind[1].

Reverse engineering the popular 555 timer chip (CMOS version) – [Link]

6 Digit Serial Display Driver with CAT4016

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6 Digit serial display project has been designed around CAT4016 IC from ON semi. The CAT4016 is a 16 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs.

A high-speed 4-wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration. A serial output data pin (SOUT) allows multiple devices to be cascaded and programmed via one serial interface. The device also includes a blanking control pin (BLANK) that can be used to disable all channels independently of the interface.

Thermal shutdown protection is incorporated in the device to disable the LED outputs if the die temperature exceeds a set limit.

Features

  • 6 Digit 1 inch 7Segment Display
  • Supply Input 3V to 5.5V
  • Serial interface up to 25 MHz clock frequency
  • LED current 20mA (Range from 2 mA to 100)
  • LED current set by external RSET resistor
  • 300 mV LED dropout at 30 mA
  • Thermal shutdown protection
  • R1,R2,R3 Current Set Resistors

6 Digit Serial Display Driver with CAT4016 – [Link]

ACS730 – Hall-effect current sensor with 1MHz bandwidth

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Allegro MicroSystems has released its first ever 1MHz bandwidth Hall-effect current sensor IC, boasting a 210ns response time.

The ACS730 provides an economical and precise solution for AC or DC current sensing and is aimed at industrial, commercial, and communications systems for motor control, load detection and management, switched-mode power supplies, and over-current fault protection.

ACS730 – Hall-effect current sensor with 1MHz bandwidth – [Link]

Fluke/Philips PM66xx Frequency Counter OCXO Upgrade

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In this post Dan Watson documents an OCXO upgrade board he designed for the Fluke/Philips PM66xx line of frequency counters.

A few months ago I purchased a Philips PM6674 frequency counter on eBay. It’s an older 9 digit counter with two channels that has a maximum input frequency of 550MHz. The design feels dated compared to more modern counters, such as my Agilent 53131A.

Fluke/Philips PM66xx Frequency Counter OCXO Upgrade – [Link]

Arduino IR remote and Software controller

IR_remote

This is a DIY Infrared remote for speakers, replacing the original. Arduino Nano and controlled via a custom .NET application and placed in a laser cut enclosure.

This one is an interesting one, it’s something we’ve been looking at for a while and figuring out how to solve it. We have sets of speakers and projectors and the users keep losing the remotes, or misplaced/stolen. Usually this wouldn’t be a problem, we’ll just contact the supplier or manufacturer and order replacements. Except we can’t any more.

We have a set of Vision AV-1000 wall mounted active speakers, connected to an EPSON projector. Projector remotes are easy to come by, but the AV-1000 remote is no longer manufactured. The speakers do not have any manual controls for the input selection, bass/treble etc. only a volume control on the back.

Arduino IR remote and Software controller – [Link]

ESP8266 Wifi controlled Home Automation

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geekrex @ instructables.com shows us how to use ESP8266 Wifi module for home automation. He writes:

ESP8266 is a great thing for starting to Wifi And IOT. It is also cheap and be used for making cool projects connected to the Internet .Learn how to make a simple IOT Project with it ESP8266 WLAN Module could be a self contained SOC with integrated TCP/IP protocol stack that may offer any microcontroller access to your WLAN network.

ESP8266 Wifi controlled Home Automation – [Link]

Rechargeable batteries with nanowires last forever

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by Harry Baggen @ elektormagazine.com:

Researchers at the University of California (USA) have developed a nanowire-based material that allow a rechargeable battery to be charged and discharged hundreds of thousands of times without any loss of capacity. This would virtually eliminate the need to replace a battery made from this material during the lifetime of the device it powers.

Rechargeable batteries with nanowires last forever – [Link]

LTC4380 – Low Quiescent Current Surge Stopper

LTC4380

The LTC4380 is an ultralow quiescent current (IQ) surge stopper, providing compact overvoltage and overcurrent protection for always-on 4V to 72V electronics in automotive, industrial and avionic systems. The LTC4380 replaces traditional shunt circuits composed of bulky inductors, capacitors, transient voltage suppressors (TVS), and fuses with a simple IC and series N-channel MOSFET solution, saving board space and enabling continuous operation through transient voltage or current surges. The LTC4380 protects downstream electronics from input overvoltage up to the MOSFET rating, while also protecting the power supply from output overload. Device current consumption is a mere 8μA in normal operation and 6μA in shutdown mode, prolonging battery run and standby time.

LTC4380 – Low Quiescent Current Surge Stopper – [Link]

USB to UART Converter with GPIO – MCP220

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The Module is based on The MCP2200, which is a USB-to-UART serial converter which enables USB connectivity in application that have a UART interface. The device reduces external components by integrating the USB termination resistors. The MCP2200 also has 256-bytes of integrated user EEPROM. The MCP2200 has eight general purpose input / output pins. Four of the pins have alternate functions to indicate USB and communication status.

Specifications 

  • Supply 3- 5V DC
  • On Board TX & RX LED
  • USB activity LED outputs (TxLED and RxLED)
  • Mini USB Interface
  • 6 + 6 PIN Header Connector for I/O and RX-TX Signals
  • UART signal polarity option General Purpose Input/output (GPIO) Pins
  • Eight (8) general purpose I/O pins
  • Supports Full-Speed USB (12 Mb/s)

USB to UART Converter with GPIO – MCP220 – [Link]