Joysticks and Smoothing Caps

Today we tested out the [ SainSmart Joystick ]. It works. What do I need it for? For demoing the ezDSP. The idea is to change parameters / swap filters through a joystick. This seems like a good application because I would get to use the SAR ADCs, change filter weights in real-time, convolve, and output some interesting  audio!

So today was the joystick check. The best part was using caps to smoothen out the transitions between different levels output by the joystick’s pots. I felt really good, because I finally realized that a cheap way to implement an interpolation function is to go analog – throw in a cap (with bigger caps giving longer, smoother transitions.) Well, its an exponential interpolation, but if you are interested in a specific polynomial interp, couldn’t that be expressed as a combination of exponentials? Probably, as polynomials do have Fourier transforms 🙂

For the filtering application I am thinking, I would rather like a smoother transition between different states, so I tried different caps out.

A gotcha to be careful about is the scope’s probe. It has two modes 1x, and 10x. My understanding is that the 10x mode offers 1/10th the actual voltage readings. I have been using the 1x mode, but I’d like to see where 10x might come in handy.



One thought on “Joysticks and Smoothing Caps

  1. Today was a significant day. For the first time in my electrical engineering career, I realized the importance of learning about the tools we rely on so heavily as engineers. Well, its easy to pick on a few keywords such as “decoupling” and “smoothing”, but true engineering demands understanding how the tools work, so that the understanding can be applied to making solutions, or expanded to form better tools. It just felt good to reflect back to physics class and think about why bigger capacitors show higher time constants, or why bigger caps tend to be electrolytic. Interesting day in science!


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