Developers can get their hands on Google's Project Ara modular phone by year's end

Google said Friday that it is nearly ready to let developers get their hands on Project Ara, with a test version of the modular smartphone to be released in the fourth quarter.

A thinner consumer version is due out next year.

The revamped Project Ara design puts the core phone technology together in the phone's frame, with room for six interchangeable module slots. Modules can also be inserted and ejected while the phone is running, Google said.

Onstage Friday at its I/O developer conference, Google demonstrated a camera module, taking a picture of the session discussing Ara. It also talked about other modules, including one to allow diabetics to monitor their blood glucose.

Google said it made enough progress with Ara that it is spinning it out of its advanced projects team and into its own business unit.

Project Ara is Google's contrarian idea that phones should be more like the PCs of old, able to be customized and upgraded with different components over time, such as a better camera or faster processor.

Of course, people stopped upgrading and customizing PCs about a decade ago.

Google had originally planned to do a market test of Ara in Puerto Rico last year, but then scrapped the plan, saying it needed more time for testing

In place of Puerto Rico, Google said it would move the market test to somewhere in the U.S. and hold it this year.