Sega Solved the Drift Issue Almost 30 Years Ago—Here’s How

With new hand-held consoles or peripheral controllers there is always the same question:  “Will it drift”? But, if stick drift is so ubiquitous, why haven’t we solved it once and for all—or has it already been solved? Let’s take a walk down memory lane, back to the ’90s. That’s the 1990’s to those of you reading from the year 2100.

Sega Introduced Drift-Proof Sensors in 1994

Those of you here in 2022 might still remember Sega’s Saturn. A scrappy gaming console from 1994/95 aiming to compete with the Sony PlayStation (yes, the original PlayStation). And even fewer of you might have enjoyed the game “Nights into Dreams” on the Sega Saturn—a game that came bundled with a revolutionary controller dubbed the Saturn 3D Controller.

That special controller was the basis for the standard controller on Sega’s Dreamcast when it was released in 1998 in Japan (one year later in most other countries). The special thing about those controllers was not only the presence of a joystick as an alternative input method to the D-pad but also the use of a tech called “Hall effect sensors.”

Sensors in the controller detected the movement of the trigger buttons as well as the position of the joystick. Back then, engineers knew Hall effect sensors aren’t as prone to wear and tear as the standard potentiometers. As we’ve explained before, a potentiometer relies on sliding part of the controller against a sensor to read resistance to measure the position. The more the wiper travels, the less reliable the center point becomes. With the Hall effect, and the magic of magnetism, there’s no physical contact between the button and the sensor.

Okay back to 2022: this tech still isn’t standard controller tech—at least not on the joystick module. Most current-day controllers do use that Hall effect tech, but just for reading the trigger buttons.

Until now.

There’s another controller with a joystick powered by magic: The GuliKit King Kong 2 Pro.

So what else can we do but take it apart next to the Dreamcast controller to see what has changed in those 25+ years?

Sega Dreamcast Controller vs. GuliKit King Kong 2 Pro

Battery tech has come a long way since this Dreamcast controller, but the King Kong 2 Pro definitely shares some similarities, both have simple Phillips screws on the exterior—granted the Dreamcast’s are moderately recessed.

Turns out 30 years hasn’t changed much. The Sega’s four Hall sensors are mounted in a star formation(green board) and the two sensors in the King Kong 2 Pro are near the joystick (black board). You may think you recognize the blue components mounted to the GuliKit stick, but while they’re in very potentiometer-like housings, those are magnets!

What Makes Hall Effect Sensors Drift-Proof?

Now that we’ve seen how tech has evolved (or hasn’t evolved) in recent years, it is time to look behind the tech and uncover the mystery of these magical Hall effect sensors and see how things actually work. Check the in-depth Hall Sensor explainer video below to get the nitty gritty (we’re talking real time multimeter readings) review of the GuliKit system.

If you’re looking for the textbook edition, let’s break this Hall effect explainer into a bulleted list:

• First, you need some electrons going from one point to another through a conductor—that makes an electrical current “I.”
• We also need a magnetic field “B” which is created by (drum roll) literally any magnet.
• When we now combine those two and have the magnetic field interfere with the electrical current, the electrons experience something called Lorentz force “F”.

That force generates an “unbalance” of positive and negative charges in the conductor which is recognized as the Hall voltage “U_H”. That voltage changes with how much the magnetic field interferes (how far away the magnet is) and can be measured.

Combine this with two sensors along two axes and you have positional data of the stick, all without any wear and tear on the measuring parts. Wikipedia sums the advantage up like this: “Hall effect devices … are immune to dust, dirt, mud, and water. These characteristics make Hall effect devices better for position sensing than alternative means such as optical and electromechanical sensing.” And yeah, you guessed it, potentiometers are electromechanical.

Why Aren’t Hall Effect Sensors Used Everywhere?

Well, they’re maybe more common than you think. We’ve seen them measure the position of motors, and can be found in many a tinkerer’s Arduino-based project. A common use case that many of you might have seen but not noticed is the water level sensor in coffee makers—a magnet drops with the water level, disturbs the electric field in the sensor, and the coffee maker tells you to fill up the tank.

But coming back to the reason we are looking into those Hall effect sensor: analog stick drift.
Although manufacturers have implemented that Hall sensor tech in their controllers for reading the trigger buttons (not just if it gets pushed but also how far you pull the trigger) it has not been seen in many joysticks, yet. So, why not? Is it too expensive, will it fail equally fast, is it not accurate enough, does it require a bigger form factor?

Hall effect setups are a few cents pricier, magnets and Hall sensors are prone to eventual wear—but we’re talking decades, so you’d think they’re worth the price. Hall sensor accuracy does depend on the resolution of the ADC (analog-digital converters) that transform the Hall effect back into electrical signals, so this could actually be a limiting factor. But it definitely isn’t about sizing, at least not any more.

We’ve come a long way since the 90’s tech of the 3D Controller, looking over at the GuliKit King Kong 2 Pro, we see proof of what’s possible. With Hall sensors the size of potentiometers, we’re approaching a golden upgrade era—it already exists for the Steam Deck’s joystick module. We’re excited to see how they will perform—not just in terms of functionality and reliability but also how easy it will be to install them.

Stay tuned for more info on stick drift, upgrade kits, and all things repair.