May 27, 2005

A4Tech NB-50: Batteryless and wireless mouse

Author: Jem Matzan

When I first saw the press release for the A4Tech "battery-free" wireless optical mouse, I figured there was some kind of marketing wizardry involved. Maybe there weren't "batteries," per se, but it was rechargeable through some other means? Or did it contain some revolutionary new mouse technology, like harnessing the kinetic energy of mouse movements? Or something more esoteric, like powering the mouse with my own sense of self-satisfaction? Turns out it's actually powered by RFID -- and it ended up being a great mouse, especially considering the $20 pricetag.

Most optical mice get their power through USB or PS/2 connectors, or through AA batteries. As any wireless optical mouse user knows, batteries don't last too long in mice -- six months if you're a lightweight, three months if you spend a lot of time on your computer. Some mice are more power-efficient than others, and some come with integrated rechargeable batteries and a charger to stick the mouse into when not in use. But sooner or later the battery situation becomes an annoyance. Corded mice can be equally annoying due to the encumbrance of the mouse cord.

The NB-50 mouse pad does have a cord, and it connects to the computer via USB. So in a sense, the NB-50 is not truly cordless and is constrained by the length of the mouse pad cord, but the mouse itself is cordless.

The mouse does not have to make direct contact with the mouse pad to receive power. You can raise the mouse about two inches off the pad before it loses signal, and can put various objects between the two without causing significant interference. I could successfully place conventional mouse pads and "gaming surfaces" such as the Ratpadz GS on top of the NB-50 pad and use the mouse on them without any trouble. Teflon mouse tape is also safe to use -- in fact I'd recommend it, as the mouse pad will become worn after months of regular use.

The mouse pad contains internal circuitry that powers the mouse. If you experience interference with other radio signals, the mouse pad has a "tune" button; press it and the device reconfigures itself on a different frequency. On top of the circuitry is a flat, textured plastic pad that is optimally smooth for mouse use. There is practically no wrist strain in using the NB-50, and I found its textured surface to be comparable to the majority of expensive "gaming surface" mouse pads. The size of the pad is less than stellar -- about 6" wide and 8" long -- but is still suitable for everything I could think of during testing.

The mouse pad cannot be operated on any metal surface. Since the warnings about this are printed on the box, in the manual, and on the mouse pad itself, I figured it was in my best interest to avoid finding out why metal and power-over-RFID don't mesh.

Physical design

The A4Tech NB-50 is a relatively comfortable mouse. I say "relatively" because true comfort depends on the size and shape of your hands. My hand fit onto the mouse with a minimum of "pinky drag" and I didn't have to arch my hand too much to fit it in a position to reach all of the buttons. This is not the most comfortable mouse I've ever used -- that title belongs to Microsoft's Intellimouse Explorer 3.0 -- but it is better than most optical mice.

The mouse includes five buttons, but the fourth and fifth buttons are hard to reach -- I couldn't press them without repositioning my hand. The primary mouse buttons are not separate pieces of plastic, but molded to the rest of the mouse frame. I've found that mice that use this design tend to last longer than the ones with discrete buttons. The scroll wheel moves in smooth steps.

Working with

Setting up the mouse with a modern installation of is simple. Just connecting the mouse should yield perfect operation, minus the two extra buttons above the scroll wheel. If you'd like to add functionality for those two buttons (the standard functions are "forward" and "back" in your browser history), create a file in your user's home directory called.Xmodmap, and put the following text into it:

pointer = 1 2 3 6 7 4 5

Then edit your/etc/X11/xorg.conf file and ensure that the following options are in the "InputDevice" section for your mouse:

Option    "Buttons" "7"
Option    "ZAxisMapping" "6 7"

If you're working from within X11, close all of your programs, log out, and restart the X server by pressing Ctrl-Alt-Backspace. When the server restarts, log in again and your mouse will have full functionality.


The A4Tech NB-50 is the best bang for the buck in an optical mouse that I have seen. It's inexpensive, durable, relatively comfortable, and technologically impressive. I used it for everyday work and to play Unreal Tournament 2004 and never had any complaints about it. If you buy this mouse, spend the extra $5 and get some Teflon mouse tape to put on the mouse's feet. This will greatly extend the life of your mouse pad. Without the tape, you can expect to get four to six months of use out of it before it starts to wear down, making mouse movement harder on your wrist.

Using the mouse with GNU/Linux requires no special driver or other software to achieve full functionality. The NB-50 works perfectly with GNU/Linux and may also work in the *BSDs. It does require a slight bit of configuration file hacking to get the extra buttons to work, but that is a fact of all mice and

Device Mouse and mouse pad
Manufacturer A4Tech
OS Support Windows ME/2000/XP/2003, GNU/Linux, Mac OS 9 and OS X
Market Desktop users
Price (retail) $20
Previous version NB-30
Product Web site Click here
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