Is the Mindstorm kit from Lego the only way to build a robot with
Legos? Is there a way to do it for less than $200? I am a
programmer, not a mechanical engineer, but I am not afraid to tackle
No, actually a number of people use Legos parts and use their own MCU board
instead of the RCX brick. The problem is usually you already have a
Mindstorms set or two or three in order to have all the robot parts and
sensors and stuff.
The Legos Spybots are a cheaper way to go, if you just want something
simpler. These are programmable using NQC or Legos Mindscripts.
There are several under $200 robot kits available, probably one of the best
of them is the
MARKIII robot for
Parallax Inc just recently started a sale on some of their robots and they
have several now that are under $200
always are good deals as the stuff Parallax sells is heavily
documented and supported. You can't go wrong with the BOE-Bot as a general
purpose learning platform.
Non LEGO: You can get a very decent robot kit for about $100, but the
electronics are usually in kit form. If you're okay with a soldering
iron these might be a good alternative. For starters, check out:
These bases are expandable, but not like LEGO, where you can build
different snap-together creations. If you really want a LEGO-type
systems, you can still consider the Mindstorms route. Try eBay for a
Or: for about $120 you could get an already-soldered OOPicR or similar
controller, two standard R/C servo motors (you need to modify these for
full rotation), some wheels, and a LEGO-compatible servo mounting
bracket from my small robot parts company, Budget Roboptics
-- these attach to a LEGO Technic beam
so you don't have to glue anything. You can then use your existing LEGO
parts and build whatever you want.
If you need more parts, consider MEGA BLOKS or Hasbro's new BTR line, as
they offer lower-cost parts kits that will connect to LEGO. This
self-built system would actually be more flexible than Mindstorms, with
more powerful add-on possibilities.
Author: Constructing Robot Bases (Now Available)
Robot Builder's Sourcebook, Robot Builder's Bonanza
It's very difficult to do *anything* with Legos (which, near as I can
tell, are made from 24K gold with a thin plastic covering) fro under
You can certainly buy a stack of Legos and a small single-board
computer (see Circuit Cellar magazine for a near infinite list of
suppliers) and make a robot. But, unless you've got some pressing
need to build it from Legos, I can't quite see why... Note that in
our sophomore assembly language programming class we take exactly this
approach (using Fred Martin's HC11 Miniboard); the reason is so the
students can have a lot of platform freedom, and we can reuse parts
One of these days I'm going to have to write up my "perfbot" -- a
stack of cheap perfboard from Radio Shack with aluminum spacers
separating the layers. Cheap, easy, effective.
Good advice from all. If I were starting out and wanted to go the "kit"
route I would look at Gordon's stuff.
and just use
your choice of micro, I've purchased wheels and materials there, good stuff
and about as inexpensive at is gets.
Also check ebay for used BOE-bots, there's usually one up for sale just
about every week it seems.
I received the Lego Mindstorms Kit and I was not very happy with it.
Don't be afraid to tackle the mechanics yourself.
I would suggest taking a couple of hobby r/c servos and gutting the
This will give you simple and easy to mount gearmotors.
Mount them to a perf board, On the perf board with double-sided tape attach
a 9v battery (rechargeable)
And also attach a bread board. Maybe a caster in the front.
Now you've got plenty of space to experiment, including a breadboard and
And when you've taken this platform to the max, You'll know exactly what you
want different and what you can do to make that happen.
I would suggest not gutting the servos, if they can be bought or modified
for contiuous rotation.
sells pre-modified servos.
to modify servos too.
Many servos can be modified, some easy, some hard, some no way to modify.
If you use the servo electronics, it saves you from having to learn how to
use a motor controller or to wire one up.
Basically you have the MCU pulse the servos using the RC control pulses and
the servo rotates nicely. You easily have forward, reverse and stop.
It keeps your first bot on a much simpler level to get started with.
: The Legos Spybots are a cheaper way to go, if you just want something
: simpler. These are programmable using NQC or Legos Mindscripts.
Earl, Spybotics are programmable via NQC? I've got Ralph's Spybotics book,
which doesn't even hint at that - What sources are there to program these
cool little guys with NQC?
I have two Mindstorms sets, and I'm not in the least disappointed with
them. Sure Legos are more expensive than Megablocks, but they work well,
don't warp, yaddayadda. That Mindstorms brick is a pretty nice package.
Well, Ralph is a pbForth kinda guy, naturally enough. My understanding
is that you can't reprogram the Spobotics brick firmware, but both
Mindscript (which isn't bad) and NQC will work. Dave Baum has some
Spybotics information on his site, which is now baumfamily.org.
Author: Constructing Robot Bases,
Robot Builder's Sourcebook, Robot Builder's Bonanza
:> Earl, Spybotics are programmable via NQC? I've got Ralph's Spybotics
:> which doesn't even hint at that - What sources are there to program these
:> cool little guys with NQC?
Well, if you are a fanatic you could reprogram it.
It uses a Hitachi MCU (Renesas?). So you would have to open the Spybot up to
get at the board,
then figure out where to hook up the JTAG or ISP programming pins, using
something like a connector and wirewrap wire.
But they made it harder by putting the MCU under an Epoxy blob. It looks
like they cost reduced it by wirebonding the MCU directly to the PCB.
Which then makes it tricky to determine which chip they used. But since it
is so compatible with the regular RCX brick, I can make an educated guess
that the MCU is the same as in the RCX.
Then you can buy a $2,000-$3,750 C compiler IDE to program it with (don't
forget the $800 programmer module).
Fortunately, Mindscripts and NQC both work great on it. Both of these
programming languages are free.
Besides they put all the great RCX state machine stuff and RTOS into the
MCU, it's a shame to waste it all.