I'm going to go off a a basic assumption (so let me know if I'm off): You're trying to launch on Kickstarter because you believe your project could have mass-market appeal.
Even if it is more of a niche you're going after, it's not a demographically based one, so the niche is still pretty broad.
With that assumption, the first thing I would say... forget about Raspberry.
Not the programming element, just forget about talking about it. Nobody cares.
I'll qualify that - the only people that really care that your project is built using Raspberry are extra techy. That may or may not be your niche, but if it is, consider another one. From my (albeit limited) understanding, the guys who love/understand the significance of Raspberry will probably just try to take your idea and do it better, or critique everything "could've" done (which is not what you want going on in the comment section.
I haven't read the thread that Jessica mentions above, but definitely go there.
From what I've seen, kickstarter is all about leveraging the net to accelerate and rapidly spread the same simple thing that has sold products and garnered support for ideas for at least the last 50,000 years: a good story.
Sure, getting press or foundations to drive traffic is important - do it - but the key is to get the 1000 people they drive to share it with their networks.
You don't need cinematic quality video (though it could help), you just need a good story told in that short, engaging (if not entertaining) video, and people will share it. In terms of traffic, that's the point.
Of course, you really want people to buy it, and so woven into that story must also be the demonstration of tangible value. How are you saving people energy, space, time, or money, is it believable, and do they care?
The most obvious example in recent memory would be "The Coolest." The video beautifully demonstrates the features of the cooler, yes. However, with every demonstration, the inventor is also explaining and demonstrating the benefits.
What made it a viral and commercial success, however, was the story behind it. The guy thought of every pain-in-the-posterior problem he'd ever had with a cooler and fixed them. Turns out that story resonated with hundreds of thousands of folks - they had all experienced at least some of the same frustrations, and so the solution was easy to buy.
I'd compare that to a video I saw about a microwave updated with Raspberry. It was "neat" and even sharable (especially by the techy crowd), but it didn't really solve a problem that people felt they had - it actually took longer to "tell" it what to do.
That's also why the Coolest was so successful - People "bought" the value at $299 well before the end of the video. The fact that it was offered at less in the kickstarter gave people a great deal that excited them.
So, yes, look for alternative publicity. But before you gain it, make sure you're telling a compelling story and making a great offer that resonates with people. They'll share it, and that's ultimately how you want the word getting out.