jellyfish

I found this http://www.mutr.co.uk/prodDetail.aspx?prodID=1074 and thought, you could fix three together with some kind of tilt switch and a solar panel to make an underwater balancing robot. It would look really kool in a big jar or something.

pete

oh man, that'd be awesome. A robotic jellyfish!

PS. woah!

yeh i've seen that before. Not solar powered though

Hi,

1. You'd need a heck of a solar panel to drive 3 of those pumps.
2. You don't need pumps to balance it underwater, just something to stabilize it at a certain dept and a sensible weigth deployment.

Not really. Probably wouldn't work 24 hours a day but just use a set of 2 rechargable batteries each with a panel to trickle charge them. If it's too heavy then glue on some balloons.

Hi,

Yes really (assuming it was the size of the solar panel you commented).

There's a couple of things in it that you don't quite seem to realize...
As you probably know, each set of battery cells have a certain factor of efficiency - an energy loss in the charge/recharge process, due to chemical inefficiency, heat production and self discharge.
Mounting an extra set means you have to compensate a larger loss => P_out/P_in gets smaller.

The pumps you linked to are small DC-motors, eating lots of current.
A solar panel which isn't able to supply at least P_pump/(P_charge*1.4 will be too small, and more batteries will only worsen that.
A more viable route would be to use 3 propellor motors.


Regards,

Soeren

Couldn't find any underwater motor things. Dono what they're called, waterproof motors?

Maybe I'm not following the scale of this project but if I wanted to see some motors into the water just for the sake of it I'd use distilled water and just throw some toy motor for a splash along with the battery. IIRC extra-distilled water can be bought at the drugstore (pharmacy) cuz I remember buying a bottle when I was in junior high for chemistry lab.

BTW, now that I mention it myself, there are also bottles of distilled water sold as "iron water" here. Not that it has iron, they are for using it with the iron to, uh, iron, your clothes because if you use tap water sediment will grow on the iron's steam orifices. My point: I think that one is cheaper.

...or throw it into cooking oil, or corn syrup, whichever has the less viscosity.

Hmm interesting. never seen this iron water though

go to your supermarket, they call it either distilled water or de-ionised water here

Yes really (assuming it was the size of the solar panel you commented).

There's a couple of things in it that you don't quite seem to realize...
As you probably know, each set of battery cells have a certain factor of efficiency - an energy loss in the charge/recharge process, due to chemical inefficiency, heat production and self discharge.
Mounting an extra set means you have to compensate a larger loss => P_out/P_in gets smaller.

The pumps you linked to are small DC-motors, eating lots of current.
A solar panel which isn't able to supply at least P_pump/(P_charge*1.4 will be too small, and more batteries will only worsen that.
A more viable route would be to use 3 propellor motors.


Regards,

Soeren

no, not really, just use a solar engine and a capacitor, rather then batteries, like a BEAM robot

Mmm that was my kinda idea. Don't really know how to build the circuit though or use caps. Do you put them in series like a battery and it charges up and then releases a lot more current but continueous? I really should experiment

Hi,

Oh please, get a perspective.
It's really really simple... The pumps needs a heck of a lot of power compared to even large (fo the physical size of the pumps) solar panels (and I'm not even mentioning the losses involved), so if you're happy with a slight move every third day, perhaps you might get it off, but otherwise...

But there's no need to use pumps as mentioned

Hi,

distilled (or de-ionised) water will be polluted (ionised) the moment you breathe on it and will conduct current, so that's a bad idea

You could use some kinds of vegetable oil, but they're all greasy and slightly "colored".
The higher mass would mean less upward thrust would be needed though.