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Subject: 
Re: Modular RC kits?
Newsgroups: 
lugnet.robotics
Date: 
Mon, 31 Jan 2005 15:44:11 GMT
Original-From: 
Joseph J. Strout <JOE@STROUT.NETspamless>
Viewed: 
4130 times
  
At 11:53 AM -0800 1/30/05, Steve Baker wrote:

> You may not be aware that you don't need a computer - or to do any form of
> programming in order to use the RCX with the Lego remote controller.

I know you don't need to program it, but the RCX *is* a computer, and
it seems ridiculous to use it to achieve remote control.  I can buy a
2-channel R/C car for $25, which probably weighs less all together
than the RCX and certainly costs 1/4 as much.  I should be able to
build an R/C lego model on the same scale.

> However, it's certainly InfraRed and not Radio - with all of the limitations
> that implies.

True.

> > LEGO already makes several RC cars, but at least from the ones I • have seen, they
> > are not modular...
> 
> Yeah - they are pretty much useless.  I really wish Lego wouldn't make sets
> like that...it's totally counter to the overall philosophy of the Lego system.

Agreed.  I mean, it's fine with me that they make them -- if you're
just looking for an R/C car, I'm glad you can buy a Lego one instead
of some other brand.  But it's very annoying that they're not more
modular.  Seems like they're really missing the boat on this one.

> Well, there are plenty of people who have adapted the Servo motors from a
> standard model R/C set (eg Futaba) to drive Lego parts.

Yes, and I've even seen one guy who used a servo to press the buttons
on the 9V battery pack to control a motor.  But that seems like a
very crude approach to me.  It only works for controlling one motor
(or at least, all motors in the same way), too.

> The up-market radio controlled car people have fully proportional speed
> controllers that connect to the output of a standard radio reciever and
> generate voltages appropriate to driving small electric motors.  Seems
> like that's what you should be investigating.

Yes, I'm finding stuff like that.  I can get a receiver for about
$40, and connect that to a switch module for another $20, and have a
digital one-channel controller for $60.  This starts to make the RCX
route look attractive.  :)

I think there must be a huge markup on these R/C parts, or else they
include some powerful capability I don't need.

> Another possiblility is to buy a cheap R/C toy and rip that apart.

Yes, that is seriously starting to look like the best option.

I'm still intrigued by the wireless transmitter/receiver boards from
Radiotronix.  These are $4 to $5 each.  But they operate at high
frequencies (e.g. 418 MHz, compared to the 27 or 40 MHz typical of
R/C toys), and they seem require a fairly large amount of support
circuitry.  Sample schematics are provided by the company, but I
think it's probably beyond my electronics skills to actually build
something out of them.

For somebody better with a soldering iron, though, these seem like
they might be a good approach.  Or, somebody could figure out how
those $25 cars are able to send and receive signals so cheaply --
there MUST be some source for R/C systems on a chip -- and build
custom LEGO bricks out of that.

Thanks,
- Joe

--
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|    Joseph J. Strout         Check out the Mac Web Directory:     |
|    joe@strout.net           http://www.macwebdir.com/            |
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Message is in Reply To:
  Re: Modular RC kits?
 
Joe Strout wrote: > I knew that, and thank you, but it's not what I'm asking for. I don't have an > RCX, nor would I want to use one for this. I need *radio* control, not remote > (infrared) control, and I don't want to involve a computer. I (...) (22 years ago, 30-Jan-05, to lugnet.robotics)

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