the water is the only way to give energy to the robot, how to do this ?

[robota]

i want to build a robot that the only energy that the robot have is that i put water into the tank in the robot
and this water give energy to the wheels and to the electrical circuit
i will happy receive advises
thanks
robota

[Asellith]

The easy way would be to have a generator hooked to a water wheel. The tank empties onto the wheel and it generates power as it rotates. This can be stored in caps like a solar robot and used to jump short distances at speed or move slowly. You might even want to consider using the waterwheel to create voltage with the generator as well as directly drive the wheels.

Or you could build a hydrogen fuel cell. Not up on my fuel cell theory but I think one of the types can take water and convert that to hydrogen then back to water and produce electricity.

[awally88]

mmm fuel cells.. Hydrogen fuel cells probably wont work due to the fact that the energy needed to extract hydrogen from water is greater than the energy which is produced from combustion of hydrogen.

Also with a waterwheel I'm unconvinced that it would produce enough energy to be worthwhile, unless you have it drive to a tap everytime it needs power and have the pressure from tap water turn a water wheel turbine.  However I believe that that would be hard to implement.

I personally don't think that water power will work, if you are trying for new-technology solution it would probably be better to try something like solar panels as they can be used with relative ease.

Awally

[Asellith]

A Steam engine would work. And be cool. However that needs more then just water because you need a heat source to make the steam.

[AndrewM]

Does it have to be water, or can it be any type of liquid?

[Rebelgium]

I must say I think your goal is very unrealistic.
imho

[SixRingz]

Well it is certainly a tough goal... I think getting enough electricity from the water will be hard, but it is an interesting thought nonetheless! In my mind right now I'm thinking: "Does all robots need electricity?". How about building a robot driven only by kinetic energy from the water.  Impact sensors could change the waterflow to create different behaviours. How cool wouldn't that be? 

[Nyx]

Dissolve HCL in the tank, put in two electrodes made of different metals

[shlodo]

I think its impossible.... The weight of the amount of water required to generate any amount of power (by means of potential energy) will be more than what the electricty u produce will be able to do work in moving the robot. That is, u need more water to produce more energy, but that makes it heavy so u need more energy to move the water.

Hydrogen fuel cell would work, Heaps of people have made homemade versions of these, but u would be producing hydrogen not electricity. U could use this hydrogen to drive a small generator or a tiny combustion engine like from an rc toy. I think that 's the only way u'll be able to use water alone to create such power. Check out these vids:

http://youtube.com/watch?v=t5oNg3-0SOM

http://youtube.com/watch?v=gYRYhoudevQ&feature=related

This will be pretty impressive too because its supposed to be impossible as pointed out earlier, however I think our concept of the conservation of energy has to be revised in this case.
 We must consider the water as a fuel itself. I think thats where the extra energy comes from. They only use a 12v battery. These homemade cells really do work, I've done loads of research already. If ur interested check out a guy called Stanley Meyer (youtube his name) who made a car that runs on water. Many other people have done this, thousands, check out a a dude named Daniel Dingle from phillipines. Its just a suppressed technology.

Anyway good luk

mmm fuel cells.. Hydrogen fuel cells probably wont work due to the fact that the energy needed to extract hydrogen from water is greater than the energy which is produced from combustion of hydrogen.