Two editors’ crazed quest to turn Microsoft’s home console into a portable gaming system.

Glenn Derene and Anthony Verducci

Before we discuss the wonder that is the Xbox Backpack, let’s go through the reasons why such an invention isn’t at all necessary. First, there are already two respectable portable video-game platforms: Sony’s PlayStation Portable (PSP) and Nintendo’s DS (with the 3DS coming out soon). These are lightweight, pocket-size, affordable and more than adequate for on-the-fly fun.

Second, the Xbox 360 was never intended to be portable. It is, in fact, distinctly non-portable. When you combine the main unit with its big honkin’ power supply, the combo weighs 4 kilograms. The power requirements for this beast are formidable; ours draws almost 200 watts of power (the newest version draws less) – nearly three times the load of an Apple MacBook laptop. The power supply converts AC mains current into two separate voltages of DC power, and the plug into the Xbox is totally proprietary. Unsurprisingly, no battery on the market can power it.

Add to that a delicate, spinning optical drive, the lack of an integrated display and a massive heat exhaust that requires active ventilation, and you’ve pretty much outlined the engineering challenges we set for ourselves when we stubbornly insisted on building this thing into a backpack.

Why bother? Oh, come on, you know why – because it’s there, because it’s difficult and because no portable gaming system is as cool as the Xbox 360. Plus, we’re pretty sure no one else is walking around with a dual-display, battery-powered Xbox that allows you to play Halo: Reach while camping – and we crave that kind of geek credibility.

Yet we also know our limitations. We were pretty sure we could build an Xbox 360 into a backpack with X-Acto blades, screwdrivers, electrical tape and – for the stubborn parts – a Dremel angle grinder. Yet we were also pretty sure we were going to need to hit up some outside expertise on the battery pack. So we contacted Xbox peripheral manufacturer Performance Designed Products, and begged for some help (see right for details).

Start with a strong bag

Choosing our backpack wasn’t easy. We needed something with structure, but a true hard shell was going to be difficult to work with. After a bit of searching, we found the Boblbee Amphib Pro 30, a brightorange, lightweight, ultra-modern-looking dry-bag/backpack combo constructed of ballistic nylon with foam backing (see boblbee.com). Strong, yet easy to cut holes into, the Amphib Pro was also just big enough to fit an Xbox – in other words, barely big enough to fit anything else, including our hands. As you can imagine, it’s fairly difficult to work in such tight quarters, so all of the constituent components, the wiring and the assembly sequence had to be decided upon and planned out before we hard-mounted anything inside the pack.

We knew we could get the Xbox into the backpack, but what good is an Xbox without a screen? (That’s a rhetorical question – you need a screen.) At first, we took the easy route and bought a batterypowered 17 cm Viore portable TV (South African equivalents go for around R1 100). This el cheapo set lacks hi-def inputs – sporting only a composite video minijack – but hi-def is a rarity at this screen size. Plus, the Viore has a built-in tuner for on-theroad TV watching as well. More importantly, it was small enough to be installed in one of the few crevices of unused space in the pack, so we cut a screen-sized hole in the back of the pack to fit it in.

in the back of the pack to fit it in. A screen mounted to the pack is nice to have, but it didn’t seem like the optimal solution. After all, you’d need to take off the backpack to play a game. Our quest for a truly mobile game-playing experience led us to the unwieldy piles of neglected gadgets in our lab, where a quick dig revealed an additional option – the Myvu Crystal personal media viewer. Essentially a pair of opaque glasses with tiny, built-in 640 x 480-pixel screens, the Myvu display had always seemed to us like a technology in search of a practical application. Now, combined with our completely impractical creation, it sort of makes sense. (At least, it does until one of us walks into a bus while playing Gears of War.)

When in doubt, use Velcro

As you might expect, it took many hours of trial and error and a few emergency trips to a nearby home centre and electronics supplier to wire, bolt, Velcro and tape it all together. We had to make some compromises: our 5-kg battery pack was too big to fit inside, so we strapped it to the exterior, making our high-tech bag resemble a World War II radio backpack. And at 12 ¼ kilograms total, the backpack is no picnic to carry around. Yet, astoundingly, it works.

We’ll end with a note of warning and a surprising bit of encouragement to anyone who dares attempt a mobile Xbox system: first, prepare your extensor muscles – your lower back is not going to thank you for this project. Second, if you are willing to lug this thing around, you really can take a fully networked entertainment system with you. We were able to play games as well as watch movies and even TV outside. It felt like being in a living room made of dirt. At least until the battery died.

Parts list

The Frankenpack

1 Mainboard

To fit the guts of the Xbox inside our backpack, we removed the system’s outer plastic casing, then bolted its internal metal cage to the shell of the backpack. To maintain airflow, we drilled intake and exhaust holes in the pack.

2 Drives

Like most of the Xbox’s working parts, the hard drive is hidden within the confines of the backpack. But to load games, we needed the optical drive to eject out the side. So we mounted the Xbox faceplate and the DVD drive to the outside of the pack.

3 Wireless

What’s better than a portable, battery-powered Xbox 360? A portable, battery-powered, completely networked Xbox 360! We kluged up the connectivity with an Xbox wireless networking adapter and a 3G hotspot.

4 Displays

Not one, but two displays! Our 17-cm portable TV had its own internal battery and was mounted to the back of the pack. For forward-facing action on the go, we also rigged up Myvu Crystal video glasses (prices start at around R2 000).

Power pack

Custom-designed juice box

The new Xbox 360 is a model of efficiency, specced to a maximum power draw of 135 watts. Our build, however, used an older model rated for 175 watts. The only off-theshelf battery we could think of that could handle that kind of load was a gel-cell battery of the sort used to power scooters and electric wheelchairs. But even that wouldn’t have worked, since the Xbox requires DC power at dual voltages (12-volt and 5-volt). We were in over our heads, engineering-wise, so we called up Performance Designed Products (pdp.com), which designs accessories for game systems such as the Xbox, PlayStation and Wii, to enlist the expertise of the company’s battery experts. They tested the Xbox’s power profile, then designed a 12-cell lithium-polymer battery stack with a step-up circuit and voltage regulator tuned to the Xbox 360’s power requirements. It powers our Xbox backpack for 2 to 3 hours per charge. According to PDP product developer Gerry Block, a talented DIYer could put one together, but at a US cost of R24 000, he probably wouldn’t want to.

