For over 30 years, Barry Fox has trawled the world's weird and wonderful patent applications each week, digging out the most exciting, intriguing and even terrifying new ideas. His column, Invention, is available exclusively online.

Read previous Invention round-ups:

Wall-beating bugging, Eyeball electronics, phone jolts, Personal crash alarm, Talking tooth, Shark shocker, Midnight call-foiler, Burning bullets, A music lover's dream, Magic wand for gamers, The phantom car, Phone-bomb hijacking, Shocking airport scans, Old tyres to printer ink and Eye-tracking displays.

Coffee-beer

A drink somewhere between coffee and beer could soon be on the menu. Nestec, part of the Nestlé empire in Switzerland, has filed patents in every major market round the world on a "fermented coffee beverage" that pours and foams like beer, but smells of strong coffee and packs a concentrated caffeine kick.

The beverage is made in a similar way to beer, but fine-tuned temperature control stops the formation of ethyl alcohol. So the new drink could go down well with people who want a long tall pick-me-up while driving.

Nestlé admits it was tricky to preserve the characteristic coffee smell in the production process. Coffee beans are roasted normally, and the chemicals containing the natural aroma collected in a cryogenic condenser, before being converted into coffee oil. The remains of the roast are then ground to powder, mixed with yeast and sucrose, and fermented for 4 hours at just below 22°C. At this temperature the yeast can still metabolise but does not generate alcohol.

The aroma oil is then mixed in with the liquid and nitrogen is injected to make it foam. Adding a touch of extra sugar also helps trap the aroma until the drink is poured, Nestlé claim.

Read coffee-beer patent, here.

Cellphone chaperone

Watch out nannies, baby-sitters and wayward teenagers. An innocent-looking cellphone from Sony-Ericsson also works like a remote bugging device.

It’s always good to know that a baby-sitter, elderly relative or child out late is carrying a cellphone. But it’s also worrying when they don’t answer a "just-checking" call.

The new device provides a simple solution. Software on the handset checks the number of each incoming call against an address list, to see if the caller has been previously flagged. If they have, the phone rings in the usual way but switches to auto-answer after a predetermined number of rings. So the called phone becomes a live microphone listening to whatever is happening nearby.

The device can also be remotely switched to speakerphone so that the caller can shout “are you OK?” down the line and into the vicinity of the phone. If the phone has been set to voicemail, the caller can key in a code to override the diversion and force the phone into auto-answer mode.

Read the cellphone chaperone patent, here.

Video flasher

Shooting video in low light normally means using a floodlight, but this quickly gobbles up batteries in small devices.

Now Philips Lab in Eindhoven, the Netherlands, has a new idea – a white-light LED that rapidly switches on and off, working only in the spilt seconds when its light is really needed.

The camera uses a sensor that collects light at about 30 frames per second. The timing circuit also sends control pulses to the white LED, so that it provides light just when the sensor needs it, and does not waste power while the sensor is sending its signal to memory.

This, Philips reckons, will let low cost camcorders and even camera phones handle video in dimly lit rooms without flattening batteries before the home movie, or conference call, is finished.

Read the video flasher patent, here.