#2440: ChopperChopper

Today’s invention is a new form of armament for military helicopters.

A belt of bullets (with no gunpowder) is fed up a tube inside the drive shaft of the main rotor (red circles).


This emerges from the end of a rotor blade.

At this point, a computer-controlled chopping device precisely times the separation of a bullet from its belt (white box), so that it flies off tangentially towards its target.

Each rotor blade can therefore act as a catapult arm, delivering enormous firepower (as long as the timing carefully avoids the tail rotor).

#2433: Stepstereo

Today’s invention is shoes -with sound effects.

The shoes would have ultra-soft, crepe soles, but they would also contain a pair of speakers wired to an mp3 player.


The wearer could choose a sound effect (using a wireless controller) and then, as each foot touches the ground, the chosen sound plays -as a footstep.

Aside from potential pythonesque humour (coconut shells) this could enable a user to appear more assertive by playing a loud, crunching step.

The footsteps’ volume could also be turned up by way of announcing someone’s arrival or warning pedestrians that the shoe wearer was running down a busy street behind them.

#2427: KiteKits

I read a story today about a plan to create planet lander craft in the form of kites.

Today’s invention takes this a step further.


Imagine dropping large numbers of flat-sheet kites over any planet with an atmosphere.

These would glide down -each landing very gently.

The kites would each have a small electric vehicle attached to one corner, allowing them to move across the ground and self-assemble at one location.

Each kite would act as a single layer in a 3D printed electromechanical machine -potentially of great size and complexity.

This would then drive off and perform some mission, without ever having been shaken up on impact with the ground.

#2425: BombTomb

If a dirty nuclear bomb is planted in a city, even if it can be found, it could be very hard to defuse.

Today’s invention is a way to move any such device to safety with maximum speed.


The bomb would be placed (perhaps by a mobile robot) in a spring-mounted box atop a tunnelling machine with its axis vertical. This would also contain a small, remotely controlled explosive device.

The drill would be fired up, creating a path, perhaps through many floors within a building, towards the ground.

A cable attached to the box would allow the whole system not to crash downwards at any time.

Eventually, when ground level was reached, the drill would rapidly create a vertical shaft around the bomb in the box, channelling the spoils behind as backfill (and perhaps also pumping in concrete, if the situation allowed this).

With a deep enough shaft, the added, trigger explosive could be detonated, allowing any radiation from the nuclear blast to be absorbed by the surrounding earth.

The depth

#2397: Racquiet

It can be annoying when a tennis player decides to grunt every time they hit the ball.

My working theory is that this tendency is about more than attempting to sound dominant to one’s opponent.


I think that it’s at least partly an unconscious ploy to disguise the noise made by the ball’s contact with the strings of a racquet.

There is a lot of information contained in that signal about the impact location on the strings and about whether the ball is now backspinning or not.

Given that no-one hits the ball anywhere near the speed of sound in air, this information may reach an opponent in time to allow their body to prepare very slightly for its arrival.

Today’s invention is therefore a device attached to a tennis racquet which makes a bumping noise, loud enough to drown out the most ardent grunting, and yet stays the same, irrespective of any details of the ball’s behaviour.

This would have the effect of making it much harder for players to anticipate where the next shot was going and thus lessen the need to disguise the impacts by disturbingly loud utterances.

#2389: Batterotation

Battery chargers are a bit boring.

Today’s invention is a way to reinject a little extra drama.


Imagine a charger with no LED to indicate when the cells are charged.

Instead, there is a single small motor, fed from the mains and rotating the batteries slowly via a little gear.

When charging is complete, the batteries will have turn from showing eg a red outer side to a uniform green.

It would also be possible to have a message on the underside of the batteries, which would be revealed when they were ready.

#2388: Touchistory

In future, when we are surrounded by domestic and workplace robots, it may be necessary to identify which was the one that made a dent in the car door or dropped that wine glass.

You could attempt to film them continuously or read back location logs for every one of the joints of a humanoid ‘bot, but both these approaches would require enormous amounts of datalogging and storage.


Today’s invention is therefore synthetic ‘fingerprints’ for robots.

These machines would have minute inkjet nozzles embedded within their ‘hands’ and elsewhere on their limbs.

These would react to any contact pressure by squirting a tiny spot of a personalised spray onto the surface in question.

The prints could be applied to surfaces that don’t work for human prints (eg fur) and they might be fluorescent under UV light, so that any errors or accidents could be easily detected and the droid responsible suitably adjusted.

#2384: ConDots

The Gates Foundation recognises the importance of condom use to world health, so my application to them for funding will be based on today’s invention.

I’ve made suggestions before based on Alan Turing’s work on pattern formation.


In order to make men keener to use condoms, they should be patterned with spots (rather than stripes).

The effect of this is an apparent visual size increase, thus greatly incentivising the use of condoms.

I hope the image effectively illustrates this comparison (although the average contrast is not exactly equal in upper and lower images).

(My attempts to use other size illusions, such as Muller-Lyer were less convincing).

#2380: Biquad

Today’s invention allows cycling to continue even on frosty roads.

Two cycles have their seats removed and are then joined by a single brace which slots into the seat post location on each and keeps the frames parallel.


This component has a single seat attached, as shown.

A rider can sit and propel this stable, four-wheeled vehicle using the two inner pedals, whilst steering via the inner ends of the handlebars (which could be linked together to coordinate the angle of turn).

#2366: Divairsion

If you are an airforce tasked with enforcing a no-fly zone, or if you need to intercept a plane without destroying it, your options are currently limited.

Today’s invention is an unmanned aerial vehicle which might help.


This is capable of flying at great speed and with none of the manoeuvring restrictions imposed by a flesh-and-blood crew.

The aircraft would approach and attach itself across one of the control surfaces of the target plane (probably using small harpoons and a number of high-tensile wire lassos).

It would then fire a retro rocket, causing both craft to slow significantly and allowing other such interceptors to catch up and latch on to flaps or ailerons.

Their coordinated activity would allow the target plane to be directed away from its current course and forced to make an emergency landing onto eg a nearby body of water (or a remote runway using the UAVs’ own wheels).

In this way, interesting military secrets could be obtained or terrorists thwarted, without loss of life.