Hacking with LEGO Bricks
NOT for the LEGO Purist!
Graphic images involved!
Turn back now!
( LEGO is a trademark of the LEGO companies)
( I am NOT affiliated with the LEGO companies )
Confessing my sins (and tips)
I have used…
• Cyanoacrylate (“Super-glue”)
• Hot Glue
• Xacto Micro-saw
• Dremel moto-tool
• SOLDER!
• Use Non-LEGO elements!!
Graphic Image Desktop
Got non-LEGO scrap parts?
• A use for non-LEGO bricks and plates!
• Hold your precious LEGO while you cut,
saw, glue and solder them!
• You don’t want to
waste your LEGO
• You don’t care if
you damage the
non-LEGO bits!
Start simple, and practice
• Cutting my first green 2x2 tiles into a
pair of 1x2 tiles for a roof project was
tough, but I learned from it;
• Practice on non-LEGO parts first!
• Use non-LEGO parts as a saw guide
• Hide the “cut side” under other parts
• Use a micro-saw to minimize loss/gaps
Making Adapter Tracks
• Have you ever needed a 1/2 straight?
• When you are
nesting loops of
track, that 5-inch
straight track is
a big shift, when
you need 8 studs
Two straights, two adapters
• Sacrifice two regular straight tracks, and
you get a 1/2-track and a 1-1/2 track
– Cut the tracks at the 1/4 to 3/4 point
– This puts the junction on a 2x8 “tie”
– The split tie is how you align the parts
• You can do this with curves and switch
track as well, but you need to be careful
Align your track parts!
• There will be a gap from the saw to fill
• Use non-LEGO to align the parts
• Now solder the
railhead parts
• Short, quick
soldering!
• Copper foil?
Add some Copper Foil Tape
• Cut and lift the railhead
•
•
•
•
Align the track
Carefully add foil
Anchor the railhead
Hot-glue rail in place
Stiffen your track joints
• LEGO braces the
joints of their track
• You should also
brace your joints!
• AFTER soldering.
• If you don’t, your joints may bend under
pressure while assembling them…
Smooth out the solder joint
• Trains and cars bumping over a bad
joint will derail a train and stop your fun
• You can either sand it, or cut it flat!
• Inside the
gauge, and
top of rail,
get the work
Was it worth it?
• I have these parts on my shelf railroad
• I think my club benefited from this effort
on some of our public displays.
For me, it was.
Track Power Extensions
• You cannot get sufficient power across
a long distance using the normal LEGOsupplied power extension cables.
– Wire gauge is too small for long haul…
– Adding train motors adds more load…
– Adding more cars, (or causing a motor to
“stall”) adds more load.
• LEGO designed this for safety!
Why I made my decisions
• PNLTC Guinness 2000 layout
• Hard to get LEGO 1-meter power cords
– They didn’t perform well daisy-chained
• The Far End of our layout was 30’ off!
– Trains slowed as they got to the far end
– Trains sped up as they came back…
• We wanted consistent train speed
Debugging a big display…
• Hot days/rooms will aggravate the
thermal safety devices in Track Power
Controllers and in Train Motors!
• Thin wires loose more power over a
given distance than larger wires.
– This holds true for the railhead! You lose
more power as you go farther from the
power feed points! You need more power!
To splice, or not to splice?
• Splicing thicker wire is less work, but is also
less efficient.
– But, how much power do you need?
• Soldering to the rail is easy enough
• Soldering to the 2x2 power brick will require
some grinding as well!
– But it will be WORTH THE EFFORT!
• Try 18-gauge wire. Maybe speaker wire?
Opening the 2x2 Power Brick
• Use two fine, flat screwdrivers
– Two tabs near the cord
– Two more on the other end
• Approach from the bottom
• Be very slow and gentle…
• You should wind up with two
pieces in the end… --->
Preparing the power brick
• I use a small router bit in my
Dremel tool,to widen the
trough that supports the wire.
– Be careful to preserve the tabs
– You can dig down a bit…
• Finally, carefully solder in
between the studs like this
– Polarity is going to matter…
Soldering to the Railhead
• Pick an area near a wire pass-through
gap on the bottom edge of the track
• Prepare your wire (cut and strip it)
– Only one wire goes under the track…
• Rough the area on the “outside”edge
– Scratch with a scribe, or light steel wool
• “Tin” the spot first, before you add wires
– Only heat the outside edge, not the top
Railhead Clues
• Find the wire pass-through
– Wires solder to the “outside
edge”, below the top of the
railhead so trains won’t derail
– A dab of hot glue holds the wire
• Only one wire needs to cross
for a track power connection
• (Only the white wire here…)
What else can I hack?
• Why tie up Track
Power Controllers to
power many models?
• Make an adjustablevoltage power brick!
– Add a 2x2 power brick
(now you’ve done it!)
– Stack a few models
on this same power
What about Mindstorms Stuff?
• I’ve only hacked with the RCX bricks.
– I’ve seen some interesting sensors.
– I wanted to trigger train automation.
• I tried optical
sensors, but
they are bulky,
take up space
Hide-A-Train Idea
• I originally heard this at the set-up
session for a Vancouver LTC display
• Mix a Hogwarts train with freight train
• Paced to leave the platform after the
freight, and follow around the loop
• Diverted to a hidden siding, to wait a
random number of freight-loops & return
What would you need?
• Automated switch points (2)
– Only divert from the main line to the siding!
– Switches allow re-entry from the siding!
•
•
•
•
•
Isolated track power
Gradual power to start the train
Some type of sensors to say it is safe
Sensors to say Hogwarts is parked
A random-loop counter (Mindstorms)
Magnetic Reed Switches
• Two contacts enter the reed from
opposite sides, meeting in the middle.
• The reed works when opposites attract.
– One contact must be North, one South
• Where are the poles on your magnets?
– Test your idea with a reed switch!
– Which axis works the best?
Testing the magnet axis issue
• When trains are coupled
the reed switch should
be in-line with the track
• But, the first and last
couplers usually pivot 90 degrees!
(The reed cannot sense them!)
What is the best way?
• I built a fixture to try all three axis’
– Adjustable
positioning
– Lights if
the switch
is tripped
• Here’s the best axis
to sense train couplers
Building a Reed Switch sensor
• All it takes to build a basic switch
– LEGO 2x2 brick
power connector
(cut a cable?)
– a pair of wires
– small reed switch
(no polarity)
– A housing to keep
the reed safe
Solder the reed switch
• Don’t clip the leads of the
switch until you are done
• Keep the cable leads
short, and solder them
close to the reed body
• Test the switch with a meter, or an RCX
– If it works, THEN you can clip the leads
Build a safe enclosure
• The switch will fit in
between the studs
• You need to trim 2
studs for the wires!
• I use a thin router bit in the Dremel, but
I’ve also used an Xacto hobby knife too.
– Test-fit the switch before you proceed!
Make the tiles to cover it…
– Left: remove one
edge of the tile,
and part of the
inside surface
– Right: remove one
edge, the center
stud, part of the
inside surface, and
notch other edge
Uses for the Reed Switches
• Robot cows ->
• Level crossing
• Train pacing
(block control)
• Use a few in parallel, if it works
• Use a resistor plate to save inputs
Test-fit the tile covers
• First try the tile that protects
the cable and the reed.
– Make adjustments as may be needed
• Check the fit of the second tile
– The reed it just a little taller than the space
under the tiles, so you may need to grind
the inside-edge of the tiles for a good fit
– Seal with hot glue, or CA
Track Power Isolation
• Useful for “Block Control” of tracks
• Controlled by hand
or by Mindstorms!
– Original train pacing
project developed by
Tony Pratkanis, using
all-LEGO part for a
BayLUG public display
How Block Isolation works
• Start with a normal loop of track,
powered by a speed controller.
– Now, electrically isolate one section
of track from the loop (the red track)
– When the train motor gets here, it
stops because there is no power.
– Add a switch, so you can apply the
loop power when you want it to go…
Step 1: Miniaturization!
• I replaced the LEGO switch
and track power connectors
with a pair of Reed Relays
• I would drive them with an
RCX, or a 9-volt battery box
– The reed relay is a reed switch
with a wire coil wrapped around
the reed switch.
I built it onto a straight track
• I used the micro-saw to make a gap
• Hot glue to tack
down the railhead
• Set the relays back
from the track, and
kept the profile low,
below the trains…
Step 2: Make it simple!
• Short structure
• Self contained
– To isolate the
block, just add
power.
• Fail-Safe
– No power?
No isolation!
Step 3: Make it reliable!
• I soldered to the outside of
the railhead (away from the
flanges of the rail wheels)
• I made sure the railhead was smooth
and flat, so trains would not derail
• I used a reed switch sensor to detect
the passing trains instead of optical…
Why is there only one cut?
• I made one block power switch track.
(The isolated section is to the right)
• The other track simply has a micro-gap
But how big is a Block?
• The white building hides the RCX
• The red tiles indicate the block limits
Track Cleaning Tools
• Even a Kleenex is a light abrasive…
• You will eventually wear off the metal
on the railhead if you clean your track
• But track should be cleaned once in a
while to preserve it’s service lifetime!
L-Gauge Track Cleaning Cars
• Centerline was first, Aztec was second.
• Aztec bought Centerline, retired both!
RCX Level Crossing Program
• Basic flow is
waiting for a
passing train
to get near
the crossing
– Start lights
– Lower gate
– Wait for train
• Two of the
process
flows are
pretty busy,
moving the
gates!
• Two others
do nothing!
Thank you for attending!
• I’ve very glad that you came to BbtB
• Thanks for attending my talk
• You can reach me at ;
zonker@baylug.org