Subject:
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Re: RC control on Pneumatics, gearboxes and polarity switches
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 8 Aug 2000 09:11:00 GMT
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Viewed:
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1753 times
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> Okay! Are you planning on renting a garage for it?:)
LOL, that might be a great idea ;)
> I can't see a solution to the problem with only 5 controllers (servos
> or whatever). But how about splitting the functions up, you need a
> channel to Rise/lower support legs next to the crane and a channel to
> switch to crane mode, which leaves you with three channels to drive
> the thing. You need to build soem circuitry to handle the switching.
> In crane mode you use all five channels for the various functions of
> the crane, and the switch to drive mode should be done automatically
> when you place the crane in its rests.
I thought something like this;
The RC-controller has two joysticks that combined control four servos.
The fifth channel is a switch made for landing gears (it's an model
airplane controller).
I thought that the switch should act as a switch between truck mode
and crane mode.
TRUCK MODE
The first joystick controls forward/reverse of the truck and steering
I, BTW, plan to let the steering servo have direct connection with the
steering mechanism of the truck, mainly 'cause it would be easier to
drive the truck if the steering resets it self to center if I let go
of the joystick. It can be done with RCX but I have no rotation
sensors and I can't find 'em here in Sweden :(.
The second joystick should be used for rising/lowering the support
legs next to the crane.
This leaves one channel un-used in truck mode.
CRANE MODE
When I dip the switch a servo is rotating the full way to the other
maximum. This is to be used as a mechanical switch to turn on
compressors and turn of the truck functionality. This way nothing in
the lines of driving steering should happen when the servos move.
Joystick 1
Moves the crane up/down and left right.
Joystick 2
Bends the crane joint and open/close of the jaws.
This leaves one function that I want, rotation of the claw on it's own
axis. I might implement this in the truck mode or leave it out.
If I'm leaving it out I might as-well make the switch rise/lower the
support legs.
This hopefully gives me eight channels for control and one channel to
switch between the different modes.
SCHEME
Gearbox ==control axle== SERVO ==contorl axle== pneumatic switch
(the servo always moves both axles but the switch - 5th channel - is
to make sure only one of the functions is active)
This should make it possible to operate two functions with but one
servo. I hope I don't need more non-LEGO parts then the RC controllers
and the logs :)
I have a couple of polarity switches, an RCX with a bunch of switches
and some old style pneumatics. Three geared motors, two old style and
one micromotor and a turn table. No compressor though, but I'll see
what I need and then order some stuff from LEGO Service here in
Sweden. I hope they have them in stock :)
I can't afford to much in this project and I'm just back from the
black period so I don't have much of the new legos :( I think I'll buy
the 8462 Tow Truck for this project though, if I can find it. I want
the airtanks and pneumatics, wheels and the turn table.
> I would no go with pneumatics, they're difficult enough to control
> when you're having direct control of the pneumatic switches, also
> because that's exactly what they are . switches. With motors
> micromotors and some easily built circuitry, you can achieve much
> better control.
*think*
That might be a good idea. I'm going to try with pneumatics first,
since it's been so long since I used 'em. I have not used them since
my black period started :(
If I don't get it working alright I might leave the pistons for
decoration :)
Any way, design comes in second place here, first I have to see if I
can make this thingie move! I'm planning on building a test bench
today where I set up the motors and such, just to see what hits my
wallet might take from this project *shrugh*
Thanks for the comments :)
I will try to take some detail photos of a real life truck so that I
can study how they actualy are built. I know of two in my area.
Here are some pictures I just found on the net (so you folks can see
what kind of truck I'm onto):
http://www.hoglundsflak.se/images/illustra_produkter_1.jpg
http://w1.953.telia.com/~u95300020/Bilder/Magnus/Timmerbil.JPG
As you might realize I was inspired by the LEGO set 8868 that I wanted
before my black period.
http://www.lugnet.com/pause/search/?query=8868
I'm planning on putting actual wood sticks on the truck, it might be
designed to hide some controllers if they take up much space (I'm
afraid they will).
Play well and have a nice day!
/Tobbe - http://lego.arnesson.nu
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