The curious case of the Nintendo Switch and the Anechoic Test Chamber

Connection drop outs with one of the wireless Joy-Con controllers were, apparently, a problem threatening to blight a promising future for a bright young product.

The Switch, you may remember, was launched in March 2017 and the hybrid console proved a hit with reviewers and users. But within days, it became clear that many users were experiencing connection problems. And it only affected the (Clue: mechanically different) left-hand Joy-Con.

So what had gone wrong, and how did Nintendo manage to fix the performance issue?

Anechoic test chamber

Well, the answer lay in a deep, silent chamber. A Satimo anechoic test chamber, to be precise.

This is, a six-metre cube used to carry out automated three-dimensional measurement and visualisation of wireless device behaviour. It can be used to test body-worn technology using body phantoms or real live test subjects, to optimise real-word RF performance.

Sam Turner, of Cambridge Consultants, tells of how his company examined the detachable wireless controllers in great detail, comparing the original model with the latest Switch version.

“In order to analyse Joy-Con connectivity in normal use, we placed them in a hand phantom model within the chamber. As Satimo allows us to test standard wireless protocols without dismantling the devices, or placing them into a specific test mode, we were able to test the Joy-Cons with a standard wireless connection to a Switch console (whilst playing Zelda).”

“Figure 1 (above) shows the Equivalent Isotropic Radiated Power (EIRP) for a left-hand Joy-Con from an original Nintendo Switch, whilst Figure 2 (below) shows the same test with the most recent product. The performance improvements made by Nintendo are evident, with the new Joy-Con performing around 3dB higher when averaged across the 2.4GHz Bluetooth channels.”

He shares that the Switch and the Joy-Cons are built around standard off-the-shelf Bluetooth components (the Broadcom BCM20734 dual-mode Bluetooth chipset) commonly used in Human Interface Devices (HID) like keyboards and joysticks.

Hand phantom

And it turns out performance can vary in free space:

“Interestingly, the performance of the original left-hand Joy-Con is noticeably worse when measured in the hand phantom than when measured in free space. This illustrates the importance of testing RF devices in the environment in which they will be used – human tissue is very good at blocking radio signals and detuning antennas. Just because a device works well on the lab bench does not guarantee it will in its intended environment.”

“The shape of the transmit power may also have affected the performance of the device. The outage feedback from the original Joy-Con only came from a subset of users – for many users they worked fine. Figure 3 (above) illustrates the left controller in relation to the original Switch console. In this position, much of the transmitted power is directed towards the floor, or the player, rather than towards the console. In this case the connection will be dependent on multipath reflections and may perform quite differently depending on the person or room in which it is used. As the controllers can be used in different orientations, wireless performance may also depend on what game is being played.”

In conclusion, he says, the Satimo analysis demonstrated the significant impact the human body, local environment and the way in which a device is held can have on connectivity performance.

Read the full analysis »

As the story goes, there’s a happy ending. Cambridge Consultants says Nintendo’s fast fix paved the way for the Switch to sell almost five million units during the remainder of 2017.

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