Subject:
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Re: Modular RC kits?
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 1 Feb 2005 14:54:18 GMT
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Original-From:
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PeterBalch <peterbalch@compuserve.comSTOPSPAM>
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Viewed:
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1398 times
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> 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. :)
> Or, somebody could figure out how those $25 cars are able to send and
receive signals so cheaply --
In the Far East, a cheap RC car costs $4 retail. Wholesale must be half
that! Someone's making HUGE profits.
But in a $4 (or $25 in the US) car, all you get is bang-bang control (i.e.
simple on/off). A $40 receiver, $20 speed controller and $60 transmitter
gives you good quality proportional control.
I prowl charity shops and car-boot-sales buying old kids toys. The problem
is that the cheap R/C cars are much more lightly built than Lego and the
steering mechanisms can't cope with Lego weight. Tomy do a very nice range
or R/C cars for toddlers which are heavily built and well engineered.
> I'm still intrigued by the wireless transmitter/receiver boards from
> Radiotronix. These are $4 to $5 each.
I don't know those particular boards but I've used something at a similar
price from a company here in the UK.
You're lucky if you can get reliable comms from one side of a room to the
other. If you go up to, say $20 at each end them you can get fairly
reliable comms from one end of an apartment to the other. (The engineer at
the company agreed wholeheartedly with that analysis.)
But, yes, you do need extra support electronics.
> there MUST be some source for R/C systems on a chip -- and build
> custom LEGO bricks out of that.
The smallest I've used are under one inch square. But at the receiver,
you'd need to add a processor and an H-bridge for each motor and at the
transmitter you'd add a processor and pushbuttons (total external
electronics cost $8).
It sounds like a worthwhile project that ought to be commercially viable.
Until you work out the costs. Lots of subscribers to this group could draw
the hardware schematic in an hour but it would take a week to get the
firmware working properly, then another week to get pcbs made and tested.
As a commercial development, I'd have to recover at least $5000 from sales
before I started making a profit and I never would.
Which means that it has to be done as a hobby and the two weeks turns into
a year.
It's a real pity but I've never worked out what the answer is. I'd love to
spend my time designing robot electronics to make constructors happy.
Peter
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