[ Aside ] PlayStation Controllers, Obsolete Datasheets

Our senior design team has decided to work on a wrist perturbation device (more details soon…) but as of now, I am trying to learn more about motors and eccentric loads. A gaming console controller is obviously a wonderful piece of technology to loot supplies from!

So, I was able to exchange a partially working controller for a spicy chicken Chic-fil-A sandwich (food is a wonderful currency in college!) This is what it looks like inside:

Controller Controller_apart

The flexible PCB is very cool, but my eyes are on the motors (and the joysticks!)

Here’s the power draw if we fix a 1.5 V source to drive these. Of course, a battery won’t do as good a job as a wall-powered supply, but we are just characterizing the best operating conditions, right?

BigLoad_Power SmallLoad_Power

Interestingly, the PlayStation 3 controllers use two, different loads, with a heavier one on the right side. An ME friend of mine thinks that allows they might have intended to use only one motor at a time, so they can have two vibrational modes without having to design a complex system to change the mass or radius on mRω^2.

We’ll probably have to think through how many different types of vibrational stimuli we would need in our design project (again, details soon!)

Besides, the same ME friend (Roozbeh!) showed me the innards of a classic joystick that he discovered somewhere in the music building. This is one of the neatest jobs I have seen, and the power / ground planes are so cool!

ObsoleteJoyStick_Side ObsoleteJoyStick_Full

There are a couple of ICs on the other side. We looked up their datasheets, and thanks to alldatasheet.com, here they are for future reading! I am attaching these because one of the them is the first “obsolete” datasheet I have ever seen:

OP11 | SSM2018 | Go ADI!

Besides, Roozbeh showed me other cool things he had found:


Photo credits to Roozbeh!



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.