Project: PC Power-on Combination Lock? |? O J Ford


Posted on Feb 7, 2014

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


Project: PC Power-on Combination Lock? |? O J Ford
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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...




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