Author Topic: Voyager2's Robot Fish (Read 17022 times)

voyager2 · « **Reply #30 on:** July 02, 2010, 08:09:02 AM »

frostyg02uk the tail is driven by two round Electro-Magnets.
In the middle is a little metal "hammer" that is attracted by the magnet.
A pivot allows the "hammer handle" to swing back and forth, in turn driving the tail.

I'll use a plastic milk carton(cut up)to form the body with silicone-rubber to join it all up.
Yeah it is a bit ambitious for my second project...
Suppose its better then that 18dof humanoid...

Voyager2

frostyg02uk · « **Reply #31 on:** July 02, 2010, 09:30:51 AM »

I see wow. Well I guess why do something easy that everyone has done and not be challenged. Ambitious is the way to go! Im certainly rooting for your success

voyager2 · « **Reply #32 on:** July 02, 2010, 08:45:50 PM »

OK to clear it up for everyone else I've attached a Google-Sketchup file (zipped) that shows the tail mechanism.
Red shows the pivot, dark grey shows the electro-magnets, white shows the metal "hammer", and light grey shows the tail.

Soeren · « **Reply #33 on:** July 03, 2010, 06:08:19 AM »

Hi,

If you move a (2 part?) coil with fixed magnet(s), you'll have less mass to move.

voyager2 · « **Reply #34 on:** July 05, 2010, 09:01:56 PM »

Hi All,

Quote from: Soeren on July 03, 2010, 06:08:19 AM

Hi,

If you move a (2 part?) coil with fixed magnet(s), you'll have less mass to move.

Do you mean have the electro-magnet in the middle on the boom/arm/thing and have permanent-magnets on either side?

random robots · « **Reply #35 on:** July 06, 2010, 05:53:57 AM »

most likely, yeah

Selenaut-14 · « **Reply #36 on:** July 06, 2010, 06:46:52 AM »

That sounds pretty smart... If you put on on each side with attracting ends going towards each other. This not only increases the secure-ness of the attachement, but it also makes your hammer idea much more powerful.

Selenaut-14 · « **Reply #37 on:** July 06, 2010, 09:50:28 PM »

Hey, I had an idea...

If you were to find a non-flammable epoxy resin coating, you could use it to waterproof all of your electronics... Provided they are already in circuit.

voyager2 · « **Reply #38 on:** July 10, 2010, 11:07:50 PM »

So heres the new tail mechanism.
http://www.filesend.net/download.php?f=5e320258bc5d6b750e958e7c7c57fd30

voyager2 · « **Reply #39 on:** July 12, 2010, 09:37:16 PM »

Hi All,

I'm thinking of powering the electronics with a 10F super cap like the ones from SparkFun.
The coils can be powered with the two batterys 3v @ 400mAh.

Does anyone know of a place I can get 2 MOSFETS that can handle 800mAh(I want some overkill ones)

Voyager2

Alfa_Zulu · « **Reply #40 on:** July 13, 2010, 05:31:28 AM »

fishy fishy

Voyager2 asked me to post something here so I did lol

btw on a serious note, how do you mean you'll just use a capacitor to power the MCU?

Razor Concepts · « **Reply #41 on:** July 13, 2010, 08:02:28 AM »

Super caps have very very high capacity that can basically be used as a battery. I would not reccomend it as it can easily fail, which is bad in a fish.

I like fairchilds logic level mosfets, they work at 4.5 volts which is excellent. Something like a FDS6680 would work nice

voyager2 · « **Reply #42 on:** July 13, 2010, 09:14:46 PM »

Quote from: Razor Concepts on July 13, 2010, 08:02:28 AM

Super caps have very very high capacity that can basically be used as a battery. I would not reccomend it as it can easily fail, which is bad in a fish.

I like fairchilds logic level mosfets, they work at 4.5 volts which is excellent. Something like a FDS6680 would work nice

Do they work at 5v too, and can they be switched directly from the MCU?

I had a wacky idea, can i split the battery so it provides 3 @ 400mAh, from one set of conections, but can supply 6v @ 200mAh from another set?
I'm going to have two batterys at 3v @ 200mAh each...

Voyager2

Alfa_Zulu · « **Reply #43 on:** July 14, 2010, 02:00:36 AM »

umm... not entirely sure what you mean, but the mAh rating is just the capacity, so the components will only use as much as they want depending on their current draw. but you can have a 6V battery go to a regulator to 3V to power some comonents and also have the same battery power a motor for example at the 6V, or use a 5V regulator so its a little more stable.

[6V Battery] -> [3V regulator] -> [all 3V components]
|-> [5V regulator] -> [all 5V components]

for this to work you'll just need to have a common ground.

voyager2 · « **Reply #44 on:** July 14, 2010, 03:29:54 AM »

No I mean have the battery I parallel to provide 400mAh @ 3v + have them in series to provide 200mAh @ 6v, both at once.

SmAsH · « **Reply #45 on:** July 14, 2010, 03:53:11 AM »

Seems like a bad idea...

Alfa_Zulu · « **Reply #46 on:** July 14, 2010, 04:04:11 AM »

if 2 batteries are parallel their voltages don't add up, 2 3V batteries running parallel will just be 3V,
if you want 6V you'll need to run them in series.

voyager2 · « **Reply #47 on:** July 14, 2010, 05:17:05 AM »

You can become a Robot Fish volunteer!
Send me free stuff and you get your name in extra-large on my site (its under construction)
To volunteer send me a PM.
Note, as a volunteer you will not ask for payment, you will have to pay for stamps, etc.
Not bad if you live in Oz, stamps are only 60c(they went up in price

)

The following items will be accepted as "donations"

New micro-controller(I only have ATmega 168's )
One set of electo-magnets
Battery's(not leaked)
Appropriate sensors(photo-resistors,bump-switches, etc.)
Appropriate high current transistors/MOSFETs
Assorted robot "stuff" that can fit in an envelope

Want to donate?
Send me a PM or e-mail me([email protected] with your name(full), e-mail and the type of part you want to send.
I will e-mail or PM you with my address.

I am not responsible for lost, damaged or misdirected mail

Voyager2

Razor Concepts · « **Reply #48 on:** July 14, 2010, 05:23:37 AM »

Oz? With wicked witches and yellow roads

voyager2 · « **Reply #49 on:** July 14, 2010, 05:31:01 AM »

Quote from: Razor Concepts on July 14, 2010, 05:23:37 AM

Oz? With wicked witches and yellow roads

Australia you Yank

Joker94 · « **Reply #50 on:** July 14, 2010, 05:33:58 AM »

i think that it will be more effective for you if you just make an order from a site for components like MOSFETs, photo resistors and bump switches. most people chose to keep these as they are always handy as you never know when they may come in handy.

don't deem what is and isn't acceptable, be great full for anything that comes your way considering what your asking.

if you offer to pay shipping you might get a couple of things that people don't need any more etc. asking people to pay shipping is a big ask as shipping for some items cost quite a bit.

voyager2 · « **Reply #51 on:** July 14, 2010, 05:42:53 AM »

Ok i can pay for shipping, anything less than five dollars(AU$) though.
But I cant pay the donator, I will allow "Replied Payed".

voyager2 · « **Reply #52 on:** July 23, 2010, 07:47:07 AM »

I've removed the attached item from my previous post, and added a link to download it from FileSend.

Soeren · « **Reply #53 on:** July 24, 2010, 10:33:18 PM »

Hi,

Quote from: voyager2 on July 12, 2010, 09:37:16 PM

Does anyone know of a place I can get 2 MOSFETS that can handle 800mAh(I want some overkill ones)

None that can be run off 3V!
Why do you want MOSFETs?
BjTs like BC327 and/or BC337 (depending on what polarity you need) will do fine for you - or get their equivalents from Zetex to get the lowest V_ce_sat (the voltage drop) possible.

voyager2 · « **Reply #54 on:** July 25, 2010, 12:52:06 AM »

They have to switch at 3.3volts, not 3 volts.
They need to switch the tail electro-magnets.
3.7v will be the maximum they switch

voyager2 · « **Reply #55 on:** August 03, 2010, 10:19:07 PM »

Just for anyone interested, i'm going to call my fish:

FRANK STALLONE : the robot fish

voyager2 · « **Reply #56 on:** August 05, 2010, 06:26:44 AM »

My first fish body was rather horrible, believe me, it was horrible!
But lucky you, I made a second one which i call, V2
Here are some pictures, not quiet complete though:

Note the hole in the side, that's where wires, waterproof connectors and other interesting stuff will come out.
The hole in the back is where the EMs, AVR, etc. will be slotted in.

Current Progress:

Body 50% (Body V2 is under construction, V1 was embarissing)

Electronics 10% (Got almost all componets)

Mecanics 25% (Electromagnets in mail, tail is made)

Software 5% (Know how it is going to work, but need electronics)

Please excuse the fact that much of this is copied from:
http://letsmakerobots.com/node/21982

amando96 · « **Reply #57 on:** August 05, 2010, 07:19:22 AM »

Haven't fully understood how it's going to work, but good luck!
No point in using MOSFETS, just use transistors, 800mA is NOT high current, and that sparkfun 10F capacitor can only handle about 2v.

macdad- · « **Reply #58 on:** August 05, 2010, 02:21:14 PM »

Quote from: voyager2 on June 29, 2010, 09:54:57 PM

Thanks for pointing that out Razor Concepts.
I never really know "g-cm" means

The g-cm is a measure of torque just like lb-ft. In your case the actuator has a torque of 2.61g-cm. This will be easier to think of with a left-right actuator than with a standard rotational dc motor. From the actuator, if you go a centimeter out from the actuator's head, then it can move 2.61 grams back and forth. But I highly recommend you do some tests before you get that actuator(Even if you use two or three at a time). As the resistance of the water will increase the force necessary to move the fin back and forth.

Also try to make the fin as hydrodynamic as possible, to reduce "blocky" surface area which would slow down the movement of water going around the fin.

Hawaii00000 · « **Reply #59 on:** August 21, 2010, 06:24:06 PM »

Good to see that you've started the actual build. I find that if I leave it to long I lose interest

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Author Topic: Voyager2's Robot Fish (Read 17022 times)