I designed the PC Power-on Combination Lock (PCPCL) last year for my GCSE Systems & Control project. The exam board stated that we must design a product under the broad category of `Safety and Security`. I already had in mind some ideas for what I wanted to do, so I was glad that not only was the specification rather vague, but also that it exactl
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y described the topic of what I had in mind. I wanted to design a product that would increase the level of security protecting a desktop PC. Software passwords are all very well, but a way around them is just a Google search or Linux Live CD away. Clearly for the average user, that`s enough by way of deterrent, but I was interested in something for small businesses, whose PC`s may contain some sensitive information, but lack enterprise-level security. I decided my project should entail a hardware level of security, that prevents the computer from even turning on without a supplied password. With that in mind, I wrote my own design brief and specification along those lines laying out some more ideas for what the device absolutely must do, what it should do, and some looser could do` ideas. Originally, I was using combinational logic from independent gates to make just one combination of four inputs send the output, Q high. However, later, this proved messy and I ended up using a PIC microcontroller from Microchip to nip it in the bud with just a single IC, whereas using several gates obviously involved several ICs, which caused a problem trying to minimise PCB size. This wasn`t just a cost-cutting exercise, I was quite strict from the outset that the device should fit within the smaller ATX drive bay standard (3. 25 ³). Using a PIC had other advantages, too. I was able to incorporate almost all functionality of the circuit...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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