Building a better controller — thumbsticks

This is a potentiometer. The device for measuring the position of any analog thumbstick

There are very few peripherals in Cod: a monitor, a controller, a headset, and that’s pretty much it! Headsets and monitors are provided by the league, so there is very little room to maneuver in terms of improving technology with those items. That leaves the controller.

I mentioned this in a previous article on innovation in Cod, but controller innovations have been few and far between. Scuf introducing the paddles in 2012 allowed players to use more of their hand when playing and that was revolutionary. I want to look at another part of the controller today, one that hasn’t gotten much attention lately.

Thumbsticks remain a big issue for professional console gamers

The thumbsticks themselves are a big issue when using a controller frequently. The grip and friction caused by frequent use can cause tearing and expose the plastic underneath. Once this happens, it makes the stick very hard to use.

I think every person who has used a controller frequently knows this pain

A compounding problem here is that, with a traditional controller (not Scuf/BB/etc.), the thumbsticks are difficult to replace and impossible to replace without unscrewing the backing and removing the circuit board to expose the sticks from behind. This is something players don’t want to do and is also potentially bad for the lifespan of the controller. Scuf and Astro now have products that allow for easy thumbstick removal without taking apart the controller. However, this doesn’t solve a much bigger problem with thumbsticks:

Stick Drift

Stick drift has come into the news recently with people showing that Sony is making controllers that are basically guaranteed to get stick drift, but, as I mentioned, there is no easy way to replace sticks in a traditional ps4 controller. This is like when Apple makes iPhones start to have battery issues just in time for you to buy the latest model. It is more expensive to fix the issue so you are forced to buy a brand new product. Watch this video for more on the stick drift scandal:

Probably the most interesting info about stick drift and controllers in general, to me, is that the mechanism for controller thumbsticks is very old. Each thumbstick uses two potentiometers to tell the controller where the sticks are. Without going into too much detail, a potentiometer is basically just 3 parts: a track, a wiper that moves along the track as the thumbstick moves, and a fixed contact point.

The fixed contact point on each end (1 and 3), wiper (2), and conductive track that a current is sent through.

We can measure an electrical current between point 1 and the wiper (2). If the wiper wasn’t here, the current would run fully between 1 and 3 in the above diagram, but the wiper shortens the electricity’s travel and the voltage is lower, proportional to how close the wiper is to point #1. The relative voltage can tell us exactly where the wiper is. Since the wiper is moved by a thumbstick, we know where the thumbstick is moved as well. There are actually two potentiometers in each controller thumbstick, one for the x-direction and one for the y.

This video does a great job describing how the joysticks work with potentiometers:

You don’t need to understand exactly how the thumbsticks measure position, you just need to know one thing about how they work: a metal wiper rubbing along a metal track. Any time there is friction, the lifespan of the product drastically shortens. The metal track slowly stops sending a reliable signal as the wiper wears against it. Stick drift actually comes from the potentiometer not being able to tell when the stick ISN’T being moved anymore, hence the drift.

Flashback to the year 2000

The Playstation 2 is released in October 2000, with a new controller designed for it. I’m sure the PS2 controller brings much nostalgia to many people, but I bet you didn’t know that the mechanism under each thumbstick is exactly the same as the PS3, PS4, AND new PS5 controllers would have.

The potentiometers are the silver boxes with green cases covering each metal track (top)

The above image is from 2008 in PS2 controller blog.

See if you can spot the potentiometers here. PS5 controller release

This image is from a 2020 video of the new PS5 controller. Notice anything similar? Sony has not changed potentiometer parts AT ALL since 2000. This is not unique to Sony, either. Nintendo is also currently facing lawsuits for joystick drift because of these EXACT potentiometers (same brand too!). Microsoft mirrors its competitors with outdated tech.

Another issue that can cause stick drift is debris. This is why thumbsticks have a domed cover on the bottoms, to protect from dust accumulation. However, it will happen, and faster with more frequent use. The push-button action of the thumbstick can also create plastic debris as the stick scratches against the controller case.

The result of stick scratching on the controller case.

Conclusion

I think the biggest issue that people don’t talk about is the fact that a PS4 or Xbox controller was not made for professional gaming.

Consider a mouse that is used in an accounting office. Adding a new button to this mouse would not make it a gaming mouse. Gaming mice have changed the weight, response time, circuitry, mechanisms, and ergonomics, just to name a few differences. Right now, the thumbsticks we use are 20-years old technology. This is a great area for innovation.