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Homemade monster servos

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Old 11-07-2009, 10:40 PM
  #1
da mad maori
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Default Homemade monster servos

ive been tring to come up with an easy cheap circuit for a while now.. (off and on)
since my first attemp.....

http://www.youtube.com/user/floatnco.../9/eimYnrCMOLI

this circuit worked wonderfully BUT i fried the boards though my own stupidity, i went to order more boards but the manufacture went outta business!!!! DAM

so it was back to the drawing board... i enlisted the help of a elec-tech head buddy to help me.......
we do have a working circuit which is in testing now.... ill let ya know the circuit when its tested and done



the idea of building a huge strong servo (wiper motor servo) for a homemade large rc is not really that hard... you dont need to know alot about electronics........
all ya doing is intersecting a standard servo before it goes to the servo motor,and routing it to bigger power switches (mosfets) and motor (wiper motor)
its almost that easy and depending on what circuit you use, it could cost you as less as $70 to build a servo that can easily take a finger off without even struggling... (lets hope that doesnt happen)

anywho some findings that we've come across are... (for mosfet based circuits)

the donor servo should be a mosfet based servo... the easiest way to tell is remove the back panel, plug it in and let it center...put a multimeter on one of the motor connectors and on ground connection... if it reads voltage (say around 2 volts) then its NOT mosfet based.... if it shows no voltage, then its mosfet ....

also almost all digital servos are mosfets........(digital = expensive)
most cheap chinese copy 1/5scale cars also use mosfet servos (GWS)


while my buddies finishing our circuit, i did find a some other circuits that work

here is an Hbride using power transistors instead of mosfets



you can use any standard servo for this circuit

this is the car its on i found on youtube

http://www.youtube.com/user/floatnco.../0/NZU1RxsbGDo

here is an hbridge cicuit using realys... i wouldnt recomened it it with abit of messing around it could work



can anyone add experience to all this there are ALOT of people that want to build these things




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Old 11-07-2009, 11:28 PM
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Default RE: Homemade monster servos

I have no idea when it comes to electronics but this could be a godsend to all us large-scalers mate.
Keep it up, your doing a great service to a lot of folks
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Old 11-07-2009, 11:59 PM
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Default RE: Homemade monster servos

What he said




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Old 11-08-2009, 12:29 AM
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Default RE: Homemade monster servos

Excellent information. Yeah the concept is as simple as using a bigger motor and having the correct power circuitry for it, same signaling and control.
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Old 11-08-2009, 08:40 AM
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Default RE: Homemade monster servos


Quote:
ORIGINAL: da mad maori

ive been tring to come up with an easy cheap circuit for a while now.. (off and on)
since my first attemp.....

http://www.youtube.com/user/floatnco.../9/eimYnrCMOLI

this circuit worked wonderfully BUT i fried the boards though my own stupidity, i went to order more boards but the manufacture went outta business!!!! DAM

so it was back to the drawing board... i enlisted the help of a elec-tech head buddy to help me.......
we do have a working circuit which is in testing now.... ill let ya know the circuit when its tested and done



the idea of building a huge strong servo (wiper motor servo) for a homemade large rc is not really that hard... you dont need to know alot about electronics........
all ya doing is intersecting a standard servo before it goes to the servo motor,and routing it to bigger power switches (mosfets) and motor (wiper motor)
its almost that easy and depending on what circuit you use, it could cost you as less as $70 to build a servo that can easily take a finger off without even struggling... (lets hope that doesnt happen)

anywho some findings that we've come across are... (for mosfet based circuits)

the donor servo should be a mosfet based servo... the easiest way to tell is remove the back panel, plug it in and let it center...put a multimeter on one of the motor connectors and on ground connection... if it reads voltage (say around 2 volts) then its NOT mosfet based.... if it shows no voltage, then its mosfet ....

also almost all digital servos are mosfets........(digital = expensive)
most cheap chinese copy 1/5scale cars also use mosfet servos (GWS)


while my buddies finishing our circuit, i did find a some other circuits that work

here is an Hbride using power transistors instead of mosfets



you can use any standard servo for this circuit

this is the car its on i found on youtube

http://www.youtube.com/user/floatnco.../0/NZU1RxsbGDo

here is an hbridge cicuit using realys... i wouldnt recomened it it with abit of messing around it could work



can anyone add experience to all this there are ALOT of people that want to build these things




When all else fails you will realize you should have just bought a tone servo.
Problem solved. Great servo.
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Old 11-08-2009, 04:54 PM
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Default RE: Homemade monster servos

[sm=50_50.gif]

Look you clearly don't understand the concept of building your own stuff.
You're wasting your time here.
Everyone knows that there's stuff available to buy.
We like to make our own stuff.

That's the whole point.






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Old 11-08-2009, 09:42 PM
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Quote:
ORIGINAL: rendezvous944


When all else fails you will realize you should have just bought a tone servo.
Problem solved. Great servo.
the only real problem i am having is finding the right components for my homemade servo.....

i dont see how buying a tone050 is going to solve this......
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Old 11-08-2009, 09:45 PM
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Default RE: Homemade monster servos

Great...more circuit diagrams!

Just got through finding out I am horrible at this stuff. But very nice to have it worked out for me. THANKS!

Question: Can you limit the travel liek a regular servo? Would not want to literally rip my linkages from their mounts. Guess a rigid bumper works as well.....so not that concerned.
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Old 11-08-2009, 09:47 PM
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Default RE: Homemade monster servos

Yeh my sparky mate gets back form work on Thursday.
I'll get him to look at it and see what he reckons.




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Old 11-09-2009, 12:26 AM
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Default RE: Homemade monster servos

Quote:
ORIGINAL: Soloratov

Great...more circuit diagrams!

Just got through finding out I am horrible at this stuff. But very nice to have it worked out for me. THANKS!

Question: Can you limit the travel liek a regular servo? Would not want to literally rip my linkages from their mounts. Guess a rigid bumper works as well.....so not that concerned.
if hooked up correctly it will do everything a standard servo will do

i didnt write those schems... i working on my own but i have seen them work....


acually if you are using a rose joint and rod to connect the feedback pot then you can just move the linkage up or down to change travel... or use EPA on ya radio


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Old 11-09-2009, 09:34 AM
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Default RE: Homemade monster servos

Your wasting your time trying to convince me I am? Their's nothing wrong with buyingsomething to solve the problem. I see you do it so how can you say your build is Homebuild. If your going to call it a home build then you can't buy any parts from a store. That includes electronis. That's my point. You can't get around it. So it's OK to do it. It makes life so much better.

Quote:
ORIGINAL: Dirty_Vinylpusher


[sm=50_50.gif]

Look you clearly don't understand the concept of building your own stuff.
You're wasting your time here.
Everyone knows that there's stuff available to buy.
We like to make our own stuff.

That's the whole point.






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Old 11-09-2009, 12:30 PM
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Default RE: Homemade monster servos

So i presume you would have made your own steel/iron,digged it up from the iron ore and melted and processed it,and then made your own nuts and bolts by using the lathe and mill to make them -which you of course have made by yourself- to call something homemade??
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Old 11-09-2009, 12:51 PM
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Default RE: Homemade monster servos

Wow, you both have lost me. Rendezvous, these guys like to make their own stuff. If you don't have anything positive to say, please don't belittle their efforts (intended or not, that is what you're doing).

My own input on this, is that servo motors (particularly the good expensive ones found in large scale servos), are expensive because they provide high torque from low power. My only worry is how much current a wiper motor will pull. Got any info on that?

PS. A LOOOOOONG time ago, I used to manufacture (just another individual on the production line, I used to install the stators) and test the wiper motors that clean the headlights on the challenger II tank!! We even use to test the coverage arc by spraying an analog 'headlight' with baby powder, then wiping it off with the wiper blade attached to the motor! CAn you imagine all those Royal Marine engineers opening the boxes and going 'Why the HELL do these things always smell of baby powder!!?!!?

I also used to test the engine cooling fans (1m hydraulic fan) for dangerous blade imperfections (spinning them overspeed on a hydraulic rig. Even in a sound proof room, the howling could be heard kilometres away!!! :O)
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Old 11-09-2009, 04:05 PM
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Default RE: Homemade monster servos

Haha Foxy that's a good anecdote about the baby powder.

Quote:
Their's nothing wrong with buying something to solve the problem. I see you do it so how can you say your build is Homebuild. If your going to call it a home build then you can't buy any parts from a store. That includes electronis. That's my point. You can't get around it. So it's OK to do it. It makes life so much better.
Ok, last time I'm gonna respond to you Rendezvous.
We're not making our own stuff "just so we can say it's home built".
We do it because we enjoy it.

Your point is ridiculous and makes no sense.
You can't call a car home built if it includes parts from a store?
Haha, ok mate...





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Old 11-09-2009, 05:39 PM
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Default RE: Homemade monster servos

Quote:
ORIGINAL: Foxy

Wow, you both have lost me. Rendezvous, these guys like to make their own stuff. If you don't have anything positive to say, please don't belittle their efforts (intended or not, that is what you're doing).

My own input on this, is that servo motors (particularly the good expensive ones found in large scale servos), are expensive because they provide high torque from low power. My only worry is how much current a wiper motor will pull. Got any info on that?

PS. A LOOOOOONG time ago, I used to manufacture (just another individual on the production line, I used to install the stators) and test the wiper motors that clean the headlights on the challenger II tank!! We even use to test the coverage arc by spraying an analog 'headlight' with baby powder, then wiping it off with the wiper blade attached to the motor! CAn you imagine all those Royal Marine engineers opening the boxes and going 'Why the HELL do these things always smell of baby powder!!?!!?

I also used to test the engine cooling fans (1m hydraulic fan) for dangerous blade imperfections (spinning them overspeed on a hydraulic rig. Even in a sound proof room, the howling could be heard kilometres away!!! :O)
most of the worlds best practical inventions/methods came of the military..

my first wiper motor servo drew around 1.5 amps with front wheels sitting on the ground of my 1/3scale build.....
front wheels sitting in SAND drew around 2.2amps i can only guess it will hang around there...
the power circuitry (for the first above schem) is rated at 12amps continuous...

for the mosfet bridge im building, the components are rated around 20amps cont, 80amps max...

there is NO WAY a wiper motor servo would draw that much but if it had to...its there

im using a 12 volt 12ah gelcell batt... 12ah will run this servo (lets say average 2amps ALL the time) the batt would last 6 hours!!! heap of power avalible

these simple circuits can alow you to just change the mosfets to higher rated fets or bank them up and you could user a wheelchair motor as a servo (stall that!!!)
or even a more rediculous , a golf buggy motor!!!!!

anywho the reason im putting this info up (heap more to come once my buddy finishes the other circuit) is ive had SOO many people msg me through youtube asking about the servo......and since there are sooo many people here home building rcs and sharing there methods i thought this is the least i could do.....


standard servo motors arent that expensive....... a buddy and i replaced a rhino digi4 motor with a Graupner speed 280 motor ($18) and it easily out preformed what ever motor the rhino uses

we also build a "bitsa" servo from the case and gears of a HPI baja steering servo,....the board from a Smartech (GWS) servo and a few off the shelf bits and peices... and it kills my Hitech 5745mg at 6volt
i would think it would also easily out torque a rhino... it may not be as fast or accurate i dont know yet.... but it should be more powerful
im getting another stock rhino soon for my boat so ill test them all then

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Old 11-11-2009, 07:33 AM
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Default RE: Homemade monster servos

What's going on in this video?
My limited knowledge of servos tells me he's using the original servo to tell the wiper motor where to stop?


[youtube]http://www.youtube.com/watch?v=gOP701BZEmc&feature=channel[/youtube]

We need a translator....


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Old 11-11-2009, 10:52 AM
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Quote:
ORIGINAL: Dirty_Vinylpusher

Haha Foxy that's a good anecdote about the baby powder.

Quote:
Their's nothing wrong with buying something to solve the problem. I see you do it so how can you say your build is Homebuild. If your going to call it a home build then you can't buy any parts from a store. That includes electronis. That's my point. You can't get around it. So it's OK to do it. It makes life so much better.
Ok, last time I'm gonna respond to you Rendezvous.
We're not making our own stuff "just so we can say it's home built".
We do it because we enjoy it.

Your point is ridiculous and makes no sense.
You can't call a car home built if it includes parts from a store?
Haha, ok mate...





I would like to see you reinvent the wheel??? why bother when it's already avaiable. Use what's already made and make your life much better. Theirs nothing wrong with that.
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Old 11-11-2009, 12:06 PM
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Default RE: Homemade monster servos

Good job Dirty_Vinylpusher, I really look up to you for the effort and research you have put into this
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Old 11-11-2009, 01:16 PM
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Quote:
ORIGINAL: rendezvous944
I would like to see you reinvent the wheel??? why bother when it's already avaiable. Use what's already made and make your life much better. Theirs nothing wrong with that.
I would like you to reinvent the understanding of us who like to make our own stuff,and not just buy something.First of all,not all have the money to buy "everything",second,maybe it doesnt exist exactly how we like it to be,therefore we get a kick out of making it by ourself and see it work better than if we have bought it.I guess you never have,or have had that feeling.
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Old 11-11-2009, 05:22 PM
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Quote:
ORIGINAL: mrmikey


Good job Dirty_Vinylpusher, I really look up to you for the effort and research you have put into this
Um...
Actually it's Da_Mad_Maori who's doing all the research here....

I just posted that video.


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Old 11-11-2009, 05:42 PM
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Quote:
ORIGINAL: Dirty_Vinylpusher

What's going on in this video?
My limited knowledge of servos tells me he's using the original servo to tell the wiper motor where to stop?

We need a translator....


that's exactly what's happening, that circuitry is already there and available, the rest of the circuitry is to control the big motor instead of the small motor that comes in the servo
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Old 11-11-2009, 05:53 PM
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Default RE: Homemade monster servos

all these circuits are using a regular servo to control a bigger motor thats the whole idea.... let a regular servo do what it does but intersect the wires before it goes to the regular servo motor and re route them to a bigger motor....

noone is tring to reinvent the wheel here rendezvous944 .....but why buy a wheel when you can make one and possibly stumble over an improvement idea.......

from backyarders like most of us to the pros that get paid mega $ to design things that arent avalible, we all have one thing in common..... if it wasnt for people like us, people like you would have nothing to buy!!!
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Old 11-11-2009, 06:07 PM
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Default RE: Homemade monster servos

it might sound stupid, and i apologize if it has been brought up
but what makes the wiper motor go side to side when its on the
car? maybe that could be used?

im sure you have thought about this.
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Old 11-11-2009, 08:32 PM
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Quote:
all these circuits are using a regular servo to control a bigger motor thats the whole idea.... let a regular servo do what it does but intersect the wires before it goes to the regular servo motor and re route them to a bigger motor....
Fair enough.
I see that in the second diagram now actually....
I just thought that he was doing it differently as the servo is connected to the wiper motor.


I'll be quiet now.



Quote:
what makes the wiper motor go side to side when its on the
car?
In a car the wiper motor spins 360 degrees continously, and an arm that is mounted offset of the output shaft, much like on a servo horn, moves a bar side to side, and is in turn connected to the wiper arms.
So there's not one motor per wiper going side to side.
See below.




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Old 11-11-2009, 09:00 PM
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Default RE: Homemade monster servos

Quote:
ORIGINAL: Dirty_Vinylpusher

Quote:
all these circuits are using a regular servo to control a bigger motor thats the whole idea.... let a regular servo do what it does but intersect the wires before it goes to the regular servo motor and re route them to a bigger motor....
Fair enough.
I see that in the second diagram now actually....
I just thought that he was doing it differently as the servo is connected to the wiper motor.


I'll be quiet now.
LOL no malice meant mate ... my keyboard articulation is not very good

it is a good question though... here i am crapping on about the hbidge circuit when ive forgoting to explain the controller (regular servo)

the servo in the video (and my first servo vid) show the regular servo connected to the wiper motor via an arm......
that is because a regular servo has a pot (dial,knob) connected to the mail output shaft where the servo horn screws onto... this pot is wired back into the regular servos electronics...
it tells the reg servos electronics what position the servo horn is...... so it knows where to bring it back........
this has to be re routed to the wiper motor so it knows where the wiper motor arm is.........

the reg servos in the vids have there motor and gears removed (apart from the main output gear which the pot is attached to)
so the wiper motor is moving the reg servo horn which is ONLY turning the pot (dial,knob) it does need this other wise the servo wont know when to stop

you can use an external pot from any electronics store but most use the pot already inside the reg servo coz its easier to mount...

(ive even confused myself)

give it a go man i reacon youll be able to pull it off.... heck if i can do it anyone can
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