The path to riches in Silicon Valley has, for decades, been paved with software.

But entrepreneurs and investors are now inching back towards hardware start-ups, writes Chris Dixon, Andreessen Horowitz investor, in a recent blog post. High start-up costs, lengthy start times, and complex manufacturing concerns long deterred entrepreneurs and investors from building a business around hardware.

But tangible technology is generating entrepreneurial energy thanks to its good performance on crowdfunding sites, the spread of tablets (which enables creators to build products that incorporate or are controlled by tablets), improved electric motors, and improved wireless connectivity, Dixon writes, citing Paul Graham.

“It’s going to be bigger than software in some ways, because what we saw with the software revolution was an efficiency play,” said Eric Klein, partner at Lemnos Labs, to Wired. “Everything became more efficient--how we do banking, just go industry by industry. That was in the digital world. Now imagine taking that same efficiency play and overlaying it in the physical world.”

Regular hardware start-up meetups that support would-be hardware entrepreneurs are on the rise in number of cities: San Francisco and New York, as well as Boston, Pittsburgh, Austin, Chicago, Dallas, Detroit, Melbourne, Stockholm, and Toronto, Wired reported. Hardware-oriented incubators and accelerators are hot on their heels, launching on both coasts in the U.S. and in China.

If you're thinking of starting a hardware company, Dixon had four key things to keep in mind, including B2B versus B2C customer acquisition and continued challenges with manufacturing.