From the new scientist back page:

Battery brainwave
IT SEEMS such a waste to throw away a battery because a digital camera
cannot draw enough power to light up the LCD screen, when you know there is
still some juice left in it to do...something. A UK company, SnailAway,
reckons it has found that use: most discarded batteries can still give a
snail or slug a small shock. Connect one to a closely spaced pair of bare
wires, and any slug or snail crossing the electric fence will bridge the gap
with its wet slimy body, feel the volts and turn tail.
You are spared the guilt of waste, the plants are spared slugs, and
hedgehogs are spared lethal slug-poison.

( http://www.newscientist.com/backpage...mg18625051.800 )

Bob

"Bob Smith (UK)" bob@nospamplease wrote in message
...
From the new scientist back page:

Battery brainwave
IT SEEMS such a waste to throw away a battery because a digital camera
cannot draw enough power to light up the LCD screen, when you know there
is still some juice left in it to do...something. A UK company, SnailAway,
reckons it has found that use: most discarded batteries can still give a
snail or slug a small shock. Connect one to a closely spaced pair of bare
wires, and any slug or snail crossing the electric fence will bridge the
gap with its wet slimy body, feel the volts and turn tail.
You are spared the guilt of waste, the plants are spared slugs, and
hedgehogs are spared lethal slug-poison.

( http://www.newscientist.com/backpage...mg18625051.800 )

Bob

Suspect whatever power is left in the cell would quickly disipate when in
contact with the moisture in the soil...H

"Harold Walker" wrote in message
...

"Bob Smith (UK)" bob@nospamplease wrote in message
...
From the new scientist back page:

Battery brainwave
IT SEEMS such a waste to throw away a battery because a digital camera
cannot draw enough power to light up the LCD screen, when you know there
is still some juice left in it to do...something. A UK company,
SnailAway, reckons it has found that use: most discarded batteries can
still give a snail or slug a small shock. Connect one to a closely spaced
pair of bare wires, and any slug or snail crossing the electric fence
will bridge the gap with its wet slimy body, feel the volts and turn
tail.
You are spared the guilt of waste, the plants are spared slugs, and
hedgehogs are spared lethal slug-poison.

( http://www.newscientist.com/backpage...mg18625051.800 )

Bob

Suspect whatever power is left in the cell would quickly disipate when in
contact with the moisture in the soil...H




I had a look on their web page. It is a bad description on NS website. It
seems to be two self adhesive copper strips that can only be used on
vertical surfaces (eg plant pots, or if your pots are raised on a paving
stone). Not much use on flower beds unless you build tiny walls around
them, and even then, the slugs could tunnel under.

They had an interesting article in NS a few years ago. A small robotic car
thing that went around catching slugs and snails, that made electricity to
power itself from the decaying bodies of it's victims. I am not a
subscriber, so cannot do a search to find the article.

Bob

Bob Smith (UK) wrote:
[...]
They had an interesting article in NS a few years ago. A small
robotic car thing that went around catching slugs and snails, that
made electricity to power itself from the decaying bodies of it's
victims. I am not a subscriber, so cannot do a search to find the
article.

The publication date wasn't shortly after the end of March, by any
chance, was it?

--
Mike.

"Mike Lyle" wrote in message
...
Bob Smith (UK) wrote:
[...]
They had an interesting article in NS a few years ago. A small
robotic car thing that went around catching slugs and snails, that
made electricity to power itself from the decaying bodies of it's
victims. I am not a subscriber, so cannot do a search to find the
article.

The publication date wasn't shortly after the end of March, by any
chance, was it?


Nope!

http://news.bbc.co.uk/1/hi/sci/tech/503149.stm

Just watched War of the Worlds last night, and it reminded me to look for
this.

Bob

I think this might be the article you refered to, but the slugbot is only
mentioned at the end.

Self-sustaining killer robot creates a stink

15:13 09 September 2004, Duncan Graham-Rowe

Microbial fuel cells digest flies to generate electricity.

It may eat flies and stink to high heaven, but if this robot works, it will
be an important step towards making robots fully autonomous.

To survive without human help, a robot needs to be able to generate its own
energy. So Chris Melhuish and his team of robotics experts at the University
of the West of England in Bristol are developing a robot that catches flies
and digests them in a special reactor cell that generates electricity.

So what is the downside? The robot will most likely have to attract the
hapless flies by using a stinking lure concocted from human excrement.

Called EcoBot II, the robot is part of a drive to make "release and forget"
robots that can be sent into dangerous or inhospitable areas to carry out
remote industrial or military monitoring of, say, temperature or toxic gas
concentrations. Sensors on the robot feed a data logger that periodically
radios the results back to a base station.

Exoskeleton electricity
The robot's energy source is the sugar in the polysaccharide called chitin
that makes up a fly's exoskeleton. EcoBot II digests the flies in an array
of eight microbial fuel cells (MFCs), which use bacteria from sewage to
break down the sugars, releasing electrons that drive an electric current
(see graphic).

In its present form, EcoBot II still has to be manually fed fistfuls of dead
bluebottles, but the ultimate aim of the UWE robotics team is to make the
droid predatory, using sewage as a bait to catch the flies.

"One of the great things about flies is that you can get them to come to
you," says Melhuish. The team has yet to tackle this, but speculates that it
would involve using a bottleneck-style flytrap with some form of pump to
suck the flies into the digestion chambers.

With a top speed of 10 centimetres per hour, EcoBot II's roving prowess is
still modest to say the least. "Every 12 minutes it gets enough energy to
take a step forwards two centimetres and send a transmission back," says
Melhuish.

But it does not need to catch too many flies to do so, says team member
Ioannis Ieropoulos. In tests, EcoBot II travelled for five days on just
eight fat flies - one in each MFC.

Donated sewage
So how do flies get turned into electricity? Each MFC comprises an anaerobic
chamber filled with raw sewage slurry - donated by UWE's local utility,
Wessex Water. The flies become food for the bacteria that thrive in the
slurry.

Enzymes produced by the bacteria break down the chitin to release sugar
molecules. These are then absorbed and metabolised by the bacteria. In the
process, the bacteria release electrons that are harnessed to create an
electric current.

Previous efforts to use carnivorous MFCs to drive a robot included an
abortive UWE effort: the Slugbot. This was designed to hunt slugs on farms
by using imaging systems to spot and grab the pests, and then deliver them
to a digester that produces methane to power a fuel cell.

The electricity generated would have been used to charge the Slugbot when it
arrived at a docking station. But the methane-based system took too long to
produce power, and the team realised that MFCs offered far more promise.

Elsewhere, researchers in Florida created a train-like robot dubbed Chew
Chew (New Scientist print edition, 22 July 2000) that used MFCs to charge a
battery, but the bacteria had to be fed on sugar cubes.

For an autonomous robot to survive in the wild, relying on such refined
foodstuffs is not an option, says Melhuish. EcoBot II, on the other hand, is
the first robot to use unrefined fuel. Just do not stand downwind.


"Bob Smith (UK)" bob@nospamplease wrote in message
...

"Mike Lyle" wrote in message
...
Bob Smith (UK) wrote:
[...]
They had an interesting article in NS a few years ago. A small
robotic car thing that went around catching slugs and snails, that
made electricity to power itself from the decaying bodies of it's
victims. I am not a subscriber, so cannot do a search to find the
article.

The publication date wasn't shortly after the end of March, by any
chance, was it?


Nope!

http://news.bbc.co.uk/1/hi/sci/tech/503149.stm

Just watched War of the Worlds last night, and it reminded me to look for
this.

Bob