Seeing new projects and innovative hacks is one of the things I love most about being an engineer. Making things work and building systems from scratch, such as this frequency counter, is the type of small project that can build a lot of motivation and inspiration in yourself and others. The theory of this project is straightforward, read input, display output. However, the complex ingenuity that it takes to create such a project separates the engineers and scientists from the everyday man.
To build this project from "Hamsterworks", two main components are needed: a Papilio One FPGA(field programmable gate arrays) board, and an eight digit seven-segment display board. Additionally, for accuracy a GPS module was added on but is unnecessary, the internal crystal within the FPGA board can also be used but is less accurate.
The FPGA board is the brains of the operation. Much like a microprocessor works, FPGAs can handle input, output, and make decisions. However, programming an FPGA is much different, they allow programmers to have control over logical gates and memory bits. So in a sense, it gives you a control over the hardware and you can “manipulate” the logic to work how you want. One advantage FPGAs have over MCUs is they can run extremely fast. Therefore, the board fits in perfect for a frequency measuring experiment.
Utilizing the GPS module for a highly accurate clock (down to a few nanoseconds) and the FPGA board, the system counts how many rising edges pass within any given second. Reading this value gives us our frequency and then it is simply displayed onto the eight seven-segment display board. While this project may be simple, it is a great way to exploit and learn about FPGA technology. Since their release in 1984 they have slowly began to gain momentum and the market for their technology is expected to grow to $3.5 billion by 2013. Seems like now is a good time to get hold of one of those development boards.
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