Elon Musk makes ‘free battery’ bet
The Tesla boss says if he can’t install a battery storage system in 100 days he will do it for free.
The 3D-printed house built in 24 hours and other tech news
BBC Click’s Dan Simmons looks at some of the best of the week’s technology news.
Smartphones conscripted in cancer fight
Scientists want volunteers to donate processing power to the search for cures for childhood cancers.
Machines v hackers
Security could increasingly rely on smart machines that spot cyber threats rather than on humans.
AirBnB raises $1bn of investment funding
Home rental company AirBnB has raised $1bn in investment funding in a deal that values the firm at $31bn.
Weird names
The stories behind CIA’s weird names for its hacking tools, from “Weeping Angel” to “Starving Weasel”.