SXSW is a marathon event, from the Interactive conference to the music festival--and it can be hard to keep all your gadgets charged and running.

So the conference organizers have collaborated with Austin-based Sol Design Lab to make the firm's SolarPumps available at locations around downtown Austin.

The SolarPump is a free, solar-powered charging station for electric bikes, scooters, cell phones, and laptops--basically anything that uses a standard electric cord to charge. Beth Ferguson created the pump in February 2009 as her project for her MFA at the University of Texas at Austin. Ferguson combined the reclaimed body of a 1950's gas station pump with solar panels to get people thinking about solar energy.

"We've used kind of a fun combination of 1950's gas pumps with solar panels for people to really start questioning and seeing the humor and really start thinking about a new form of transportation and energy for the city," she told Austin's KVUE News.

The SolarPump combines 1950s vintage gas pumps with solar panels to create an electronics-charging station. © Sol Design Lab

A new "enhanced vision system" from General Motors could help drivers by highlighting landmarks, obstacles and road edges on the windshield in real-time. Such a system can point out to drivers potential hazards, such as a running animal, even in foggy or dark conditions, GM says.

Head-up displays (HUDs) are already used to project some information--like a car's speed or directions--directly in front of the driver, through the windshield, or even through a side view mirror. These sorts of displays have started appearing in high-end cars, and typically work by projecting light to create an image on part of the windshield.

To turn the entire windshield into a transparent display, GM uses a special type of glass coated with red-emitting and blue-emitting phosphors--a clear synthetic material that glows when it is excited by ultraviolet light. The phosphor display, created by SuperImaging, is activated by tiny, ultraviolet lasers bouncing off mirrors bundled near the windshield. Three cameras track a driver's head and eyes to determine where she is looking.

"We definitely don't want the virtual image that's on the display to complete with the external world; we just want to augment it," says Thomas Seder, the lab group manager for the Human Machine Interface group at GM.

The new display, which so far has only been tested in simulations, wouldn't be incorporated into cars until 2018 at the earliest, says Seder. The team hopes to pair the technology with night vision and find a way to combine the work with other sensors in the car to keep costs down, he adds.

"I'd like to couple with other systems and not have it be a standalone. That will help cost reduce it dramatically," says Seder.

See how the system, which was developed with partners from Carnegie Mellon University and the University of Southern California, works in the video below.

Here at South By Southwest Interactive, the keynote interview of Daniel Ek, the 26-year-old founder of European music service Spotify, provided some satisfying insight into the major new music site.

Spotify has built a lovely music application that uses a peer-to-peer architecture to stream music at lightning speeds (a real improvement over the sometimes spotty service that comes with many other music streaming applications). The site is only licensed in Europe, but Ek says the site has 7 million users in 6 countries, and he's been working hard to get it licensed in the United States. Users can listen to music for free, with ads, or can pay for a subscription that grants access to perks such as the Spotify mobile app, and song downloads.

I couldn't help noticing, however, Ek's artful dodge to the question of how artists are paid by his service. The subject was broached by an audience member, who identified himself as an independent musician and thanked Ek profusely for the great application. He wanted to know how much he would be paid.

"It's complicated," was, in essence, Ek's reply. But he did reveal that it's a revenue sharing model; artists get paid a proportion of whatever Spotify gets paid, presumably based on the number of plays on the site they receive.

Ek's reply was disappointing because this is the million dollar question for many music sites. Pandora's been on the verge of going under for years in part because they've paid artists even when they couldn't afford to. It's clever of Spotify to find a way to be cash-positive where other sites have failed, but it means the artists must wait to be paid a fair rate.

There see other problems too. For example, pop stars are likely to draw the highest proportion of plays, but how does that relate to which fans pay a subscription fee? It seems that part of what Spotify will need to figure out is what brings money to the site and how to reimburse artists fairly.