Circuits & Schematics Security - 4

The most peculiar aspect of this design is that the firmware is written in BASIC. I’m a strong advocate of using C for embedded systems, and I use routinely the excellent GCC compiler for AVR development on PC and Linux platforms. But at the ...

Part 2 Part 3 Video surveillance systems have rapidly grown from being a specialized equipment for high-risk areas (like banks and airports), to the point of being standard facilities of most places open to the public. Nowadays, no shopping centre, ...

Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to ...

This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This relay can then be ...

A programmable code lock can be used for numerous applications in which access to an article/gadget is to be restricted to a limited number of persons. Here is yet another circuit of a code lock employing mainly the CMOS ICs and thumbwheel switches ...

In this Instructable I will describe different ways to block or kill RFID tags. RFID stands for Radio Frequency Identification. If you do not know about this technology yet, you should definitely start familiarizing yourself with it, because the ...

A small coil gun that can demonstrate the principal of operation of these devices can be constructed from commonly available materials in about an hour. The energy used in this coil gun is less than lethal so it can be considered reasonably safe. ...

The Geiger counter is a pretty simple device to detect radiations. Many forms of radiations from radio elements (alpha, beta, gamma) can be detected but it is more sensitive to beta and gamma radiations. The Geiger-Muller tube is a simple device, ...

PINs, passwords, secure entry systems; just about everything you access these days needs some form of passive authentication code. Heck, even that Wi-Fi router in your basement uses a mega 63-character password for enabling secure access. Before ...

Here is a white-LED-based emergency light that offers the following advantages: It is highly bright due to the use of white LEDs. The light turns on automatically when mains supply fails, and turns off when mains power resumes. It has its own ...