Google's modular smartphone initiative, Project Ara, is facing a challenge to "work as a normal-size phone and not have a fridge" in the hand of the end user, according to Ara collaborator Dave Hakkens.

Phonebloks, a modular phone concept created by Dutch designer Hakkens, is one of the templates Project Ara is based around.

“We’re trying to help wherever we can,” said Mr Hakkens, who next week flies to the US to view a prototype of the device which “looks pretty promising” despite the “big challenge” of ensuring various modules aren’t obtrusive for the user.

Project Ara revolves around different, interchangeable modules such as a camera or processor. The concept made a somewhat stumbling debut publicly last week as the prototype Hakkens referred to was brought on stage by Google's technical lead on the initiative, Paul Eremenko, during the Google I/O developer conference in San Francisco. The screen on the device froze during the presentation.

“It boots around 75 per cent of the time so it was pretty unlucky for them,” said Mr Hakkens. “There are still bugs and errors.”

As part of Project Ara, Google has created a developer prize challenge that is “aimed at the creation of novel modules that would be used daily, and for something you can’t do with a smartphone today” and which has a top prize of $100,000 (more than €73,000).

Respected US technology analyst Robert Enderle predicted in May that the project may struggle to gain sway with consumers as any successful phone "needs to be cool looking, and given their work so far with Google Glass, making something attractive doesn't appear to be in Google's DNA".

Barry Smyth, director of UCD, UCC and the DCU-based Clarity Centre for Sensor Web Technologies, said: "I find it hard to wrap my head around this as a mass consumption consumer device."

Prof Smyth said while there are “a couple of [Google] Glass developers” at UCD and Project Ara “is the sort of thing that would appeal to us”, as yet no researchers have taken on the developer challenge.

Prof Smyth can see some particular-use cases for Ara, such as a "photographer who wants a better lens" or "a health conscious person who wants to plug in extra sensors", adding that should "brands get behind different modules, such as Canon or Leica with the camera", then it could "get interesting".

Mr Hakkens noted that he recently had a conversation with headphones company Sennheiser about the project, noting they "would love to build audio speaker blocks for phones".

The basic endoskeleton of an Ara device is rumoured for release in January next year, with a likely starting price of around €40.