usb

USB Cherry MX Numpad

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Almost a year ago, I bought my first mechanical keyboard. It's a Filco Ninja Majestouch-2 Tenkeyless (with Cherry MX Brown switches). It's an absolutely amazing keyboard to type on and is built like a tank, well worth the admittedly shocking price. However, the "tenkeyless" in the name means that it does not have a numpad. The keyboard is available with a numpad aswell, but the reason why I did not want one is that I am left-handed, and much prefer the numpad to be on the left side of the keyboard. A normal numpad would be almost useless for me.

Another reason why I got the tenkeyless version was this: not having a numpad also gave me an excuse to build my own! It's taken a year, but I finally managed to get around to doing it. That is what this post is all about.

AD9833-based USB Function Generator

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One tool that I've been missing at my lab at home is function generator. They tend to be a bit expensive, so I haven't bought one. I thought this might be a good opportunity to try and make one myself. I found a pretty common DDS (direct digital synthesis) chip, called AD9833. Then just strap a USB-enabled AVR micro there and maybe some analog electronics.

This board doesn't do any of the special analog magic to allow for variable amplitude or offset for the signal. The output is fixed to 0-4v. I'm planning to make another completely analog board for adjusting amplitude and offset.

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