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After reading Dave Koudys’ conversation with fellow RTL’ers about installing a DCC decoder directly into a
Technic motor, I became inspired to actually build such a beast:
If you click on the above image and look closely, you can see the DCC decoder
sandwiched between the electrical plate on top and the motor element below. As
you can see, it’s pretty tight in there. I used a Z-scale decoder (the Digitrax
DZ123) as it’s one of the smallest decoders available, but it still required me
to trim the underside of the black electrical pad and the red insulation
material that encases the decoder to get everything to fit properly.
Here’s a view of the electrical components soldered together before
installation:
So, why is it a smart motor? Well, the idea is that you can wire many of
these motors in parallel to a single RCX output and still individually control
each of the motors(1):
Power and control information are passed along the two conductors of a standard
Lego electrical wire to each of the motors connected to the RCX output. Control
information is sent by rapidly switching the polarity of the power on the RCX
output in a specific timing sequence as defined by the DCC protocol. In
addition, each smart motor has its own unique address. The DCC decoder in each
motor listens to the control information being sent until its address is
encountered in a command packet. It then executes the command. Each motor can
then be individually set to foward/reverse (126 different speeds) or stopped.
My recent post on this subject
contains some tidbits on the programming interface for BrickOS. Some additional
construction photos can be found in my Brickshelf
folder.
In any case, I’m rather excited by this approach as it still feels very
Lego-like in its simplicity (i.e. simple 2-wire hookup). And, it’s not too
expensive - less than $35US per smart motor.
Mark
(1) That photo is actually a “dramatization” as I’ve only built one of these
smart motors so far - the others are stand-ins for the real thing... :-)
However, I’ve tested it in parallel with my
DCC brick and everything works
peachy!
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In lugnet.robotics, Mark Riley wrote:
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After reading Dave Koudys’ conversation with fellow RTL’ers about installing a DCC decoder directly
into a Technic motor, I became inspired to actually build such a beast:
<http://www.brickshelf.com/cgi-bin/gallery.cgi?i=906503
http://www.brickshelf.com/gallery/markril/RCX/DCCMotor/thumb/dccmotor5.jpg_thumb.jpg>
...
So, why is it a smart motor? Well, the idea is that you can wire many of
these motors in parallel to a single RCX output and still individually
control each of the motors
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Well, you rock! That’s exceedingly cool. Please build more! Indeed, you might
consider building a largish batch of them -- if you set yourself up
assembly-line style, you could probably knock off a couple dozen of them in a
few evenings and sell them for $40 apiece (or more).
It’s a very exciting development, since as you say, it’s very lego-like. One
RCX brick controlling any number of motors -- how cool is that?
Of course I suppose that power would become a problem if you hung more than a
few motors off one RCX output. Any thoughts on what to do about that? E.g.,
would it be possible to rig it so that the motors draw their power from another
source (an RC car battery for example), and just get the command signals from
the RCX? Or is this not an important issue?
Best,
- Joe
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Subject:
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Re: Smart Motor
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 9 Sep 2004 17:47:05 GMT
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Original-From:
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Russell Nelson <NELSON@CRYNWR.stopspammersCOM>
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Viewed:
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949 times
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Joe Strout writes:
> Of course I suppose that power would become a problem if you hung
> more than a few motors off one RCX output. Any thoughts on what to
> do about that? E.g., would it be possible to rig it so that the
> motors draw their power from another source (an RC car battery for
> example), and just get the command signals from the RCX? Or is
> this not an important issue?
Not an important issue unless you want to turn multiple motors at the
same time. The DCC electronics consumes a minimal amount of power
compared to turning the motor.
Now if we can only persuade Lego to create DCC motors! W00t w00t!
--
--My blog is at angry-economist.russnelson.com | Violence never solves
Crynwr sells support for free software | PGPok | problems, it just changes
521 Pleasant Valley Rd. | +1 212-202-2318 voice | them into more subtle
Potsdam, NY 13676-3213 | FWD# 404529 via VOIP | problems.
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In lugnet.robotics, Joe Strout wrote:
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In lugnet.robotics, Mark Riley wrote:
| |
After reading Dave Koudys’ conversation with fellow RTL’ers about installing a DCC decoder directly
into a Technic motor, I became inspired to actually build such a beast:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=906503
So, why is it a smart motor? Well, the idea is that you can wire many of
these motors in parallel to a single RCX output and still individually
control each of the motors
|
Well, you rock! That’s exceedingly cool. Please build more! Indeed, you
might consider building a largish batch of them -- if you set yourself up
assembly-line style, you could probably knock off a couple dozen of them in a
few evenings and sell them for $40 apiece (or more).
|
I imagine you could bang them out fairly quickly once you’ve done a few. But,
when I mentioned the US$35 figure, that was $16 for the decoder and ~$17 for the
motor (via BrickLink). That still doesn’t include any taxes and shipping. So,
as a do-it-yourself project, you could do it for around $35. When you consider
the margins of doing something like this commercially, it makes you realize all
the more just how much of a community service it is that companies like
HiTechnic perform.
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Of course I suppose that power would become a problem if you hung more than a
few motors off one RCX output. Any thoughts on what to do about that? E.g.,
would it be possible to rig it so that the motors draw their power from
another source (an RC car battery for example), and just get the command
signals from the RCX? Or is this not an important issue?
|
There are several solutions to this. In fact, I mention a few
here in a previous post when
discussing the DCC brick.
Other ideas include building a mini DCC booster. This would take the DCC signal
from an RCX output and amplify the current using an external supply such as a
battery box (or boxes). A small booster that handled 2-3 amps wouldn’t be all
that big, perhaps no larger than a Technic motor. (I’ve already purchased parts
for such a project - just haven’t gotten around to building it yet... :-)
Cheers,
Mark
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"Mark Riley" <markril@hotmail.com> wrote in message
news:I3r1Ez.1wGL@lugnet.com...
> After reading Dave Koudys' <http://news.lugnet.com/robotics/?n=22779
> conversation> with fellow RTL'ers about installing a DCC decoder directly
> into a
> Technic motor, I became inspired to actually build such a beast:
>
> <http://www.brickshelf.com/cgi-bin/gallery.cgi?i=906503
> <http://www.brickshelf.com/gallery/markril/RCX/DCCMotor/thumb/dccmotor5.jpg_thumb.jpg>>
Crossposted to lugnet.parts.mod -
Mmmmmmmm, modding goodness!
-Rob
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