the mechanical octopus project

[ronen]

phase one of my plan was to build a submerged raft that would move underwater

built a prototype and it was a complete failure
the idea was for a user to have like a console consisting of several bicycle brake handles
which would pull on the cables of the brakes which in turn would go right into the octopus and pull on something
in the end a holed rubber ball would contract and expand creating jet propolsion

but it turned out that the cables themselves always return the device back to its starting position.
ill try to make a new video so that you can understand more clearly

would love any ideas because i really want to make this succeed

of course this is not a men only thread!!i just didnt knew where to put it

i sent chris the video but its morning in the US so until he sees my msg ill try to elaborate a little

we were given an assignment to get inspiration form the animal world to create a toy for kids that would raise their interest in science

i decided that a mechanical animal built without engines and pumps in a way that an 8 yo kid could understand how it works would have the effect. a kid who is surrounded by mechanical animals and toys which he understands their way of operating would in my opinion have all the incentive to explore his mechanical potential

the game part of the assignment was that we would create a "battleships" game of the 21 century
and i hope you are familiar with the game
(except meg who is too young so i have no hopes there)
what would happen is that once you decide which square you want to try
you would send the submerged octopus under it and than with mechanical arms which i havent built yet it would sink whatever is above him
hence an octopus was picked

http://www.raptureforums.com/ronenmechanicaloctopus.wmv

http://www.net-games.co.il/online-ga...ttleships.html

[Carl]

Sounds like what is happening is that the ball is contracted blowing out water moving the ball forward. Then the the ball is relaxed causing it to expand sucking in water and moving it in the opposite direction.

What you need is to put a hole at the other end of the balls diameter with check valves at each hole. One valve to keep water out and the other to keep water in the ball. That way the thrust will always be in the same direction.

[ronen]

you are right to some extent
it does happen but its not the main cause
as you can (or cant) see in the video that chris kindly added i talk about this myself
but when i tried it in a small bath of water than i saw the problem was from the cable itself
it just moves all the times and moves the device with it
i am no thinking about replacing the metal cable with sewing wire

[Carl]

I can see where the cable stiffness would be a problem with such a small mass.

[ronen]

the toy is done
in the end i couldnt overcome the problems in the mechanism and had to significantly simplify the toy
to the point where im kind of ashamed to even present it
but it is what it is so i hope tommorow ill film it and upload it so you can see

[micah719]

You need something to stop it moving back.

How about a hinged rod sticking out in the direction of the water jet. The end should be grippy rubber, so it can be dragged along the bottom but when pushed against stops movement of the octopus frame. Either tilt the jet so the frame tilts and lifts the "stoppers" on the other side, or extend the rod from the other side and attach a vane that catches a part of the water jet. If the rubber stopper on the end of the rod can turn on the rod, it gives another axis of movement, or perhaps rotation. Basically some kind of anchor that it can pull up when it wants to move, but drops when it needs to stay still. Or how about making the bottom of the octopus out of grippy rubber, and direct a part of the jet so the octopus levitates on its own water cushion when it wants to move...

looks like fun!

[ronen]

You need something to stop it moving back.

How about a hinged rod sticking out in the direction of the water jet. The end should be grippy rubber, so it can be dragged along the bottom but when pushed against stops movement of the octopus frame. Either tilt the jet so the frame tilts and lifts the "stoppers" on the other side, or extend the rod from the other side and attach a vane that catches a part of the water jet. If the rubber stopper on the end of the rod can turn on the rod, it gives another axis of movement, or perhaps rotation. Basically some kind of anchor that it can pull up when it wants to move, but drops when it needs to stay still. Or how about making the bottom of the octopus out of grippy rubber, and direct a part of the jet so the octopus levitates on its own water cushion when it wants to move...

looks like fun!

those are good ideas
but presentation is day after tommorow and i still have all calculations and solidworks drawings to make
so.. next semester
and i already have an idea:
a mehcanical card dealer! what do you think?

[micah719]

I was a croupier for 3 years, back in my sinful pre-Lord days. At 2am, dealing 5000+ cards an hour, I was mechanical. So were some of the players, but I suspect they may have been chemically augmented.

Sounds like an interesting project, how many cards, what speed, what kind of application?

[Meg]

the toy is done
in the end i couldnt overcome the problems in the mechanism and had to significantly simplify the toy
to the point where im kind of ashamed to even present it
but it is what it is so i hope tommorow ill film it and upload it so you can see

Congrats Ronen. Looking forward to seeing the project!

[king'sbloomingrose]

Sounds really really fun! Are you studying to be an engineer? My older brother is an engineer too, only he works as a chemical engineer. I'd love to see the octopus!

[ronen]

thanks for the replays
always nice to see that people take interest
i made a mistake though
in the whole excitement of presenting the project i forgot to take pictures
so all i have at my computer are pictures of previous models (that didnt work)
they are sort of raggedy but that is on account of being only used to see if the mechanism will work or notoctopus1.jpg

the final version of the project was made out of silicon casting which didnt turn out too well
and was based on water pipes
but frankly it wasnt very good

[ronen]

octopus1.jpg

the pic with the pipe was not the one i intended to post...

[Meg]

thanks for the replays
always nice to see that people take interest
i made a mistake though
in the whole excitement of presenting the project i forgot to take pictures
so all i have at my computer are pictures of previous models (that didnt work)
they are sort of raggedy but that is on account of being only used to see if the mechanism will work or notoctopus1.jpg

the final version of the project was made out of silicon casting which didnt turn out too well
and was based on water pipes
but frankly it wasnt very good

I looked at all the pictures, Ronen, but I don't know much about engineering. What were you trying to make it do, and what sort of problems did you have with it?

[ronen]

i tried to make a toy that swims underwater in a distance up to several feet from the user
the challange was that i wanted the user to have complete control over the toy like with a remote
except that i wanted to use no electricity in the project
i was pretty certain at first that such things existed since it must have been needful a few centuries back
but it turns out that finding help on this subject was almost impossible
using steel cables for the connection between the user and the toy didnt work because they would just force the toy back into its starting position
eventually i built the submarines game
but i used pumps and latex tubes which was too basic for the level im supposed to be competing on now
but i just couldnt find any other way to go at it

[Meg]

Interesting challenge, Ronen, trying to make it work without electricity. There was indeed an early submarine, that was based on a concept thought out by Leonardo da Vinci. It did work, in its own way, and without an engine, but some gearing was still required for propulsion, as shown by the line sketch:

"Turtle": the first military submarine - Other - Sea

I think there's still a lot of merit to your idea, but I still stick to my squid concept:



They have those 2 long arms for reach, and the shorter ones for control. Its the long ones I would have seen as useful for your design, but however they're powered, they still must be caused to move and controlled. The key would be inside the cable. I hope, when you have time, that you continue to tinker with this concept, its a good one. And I pray that your next project be both challenging and fulfilling

[ronen]

very interesting article
thanks meggie