Hacking with LEGO Bricks

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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 )

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Confessing my sins (and tips)

• I have used
• Cyanoacrylate (Super-glue)
• Hot Glue
• Xacto Micro-saw
• Dremel moto-tool
• SOLDER!
• Use Non-LEGO elements!!

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Graphic Image Desktop
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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 dont want towaste your LEGO
• You dont care if you damage thenon-LEGO bits!

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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

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Making Adapter Tracks

• Have you ever needed a 1/2 straight?
• When you are nesting loops oftrack, that
  5-inchstraight track isa big shift, when you
  need 8 studs

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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

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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, quicksoldering!
• Copper foil?

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Add some Copper Foil Tape

• Cut and lift the railhead
• Align the track
• Carefully add foil
• Anchor the railhead
• Hot-glue rail in place

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Stiffen your track joints

• LEGO braces thejoints of their track
• You should also brace your joints!
• AFTER soldering.
• If you dont, your joints may bend underpressure
  while assembling them

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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 thegauge, andtop of rail,get the work

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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.

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Track Power Extensions

• You cannot get sufficient power across a long
  distance using the normal LEGO-supplied 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!

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Why I made my decisions

• PNLTC Guinness 2000 layout
• Hard to get LEGO 1-meter power cords
• They didnt 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

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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!

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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?

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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 twopieces in the end
  ---gt

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Preparing the power brick

• I use a small router bit in myDremel 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

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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 outsideedge
• Scratch with a scribe, or light steel wool
• Tin the spot first, before you add wires
• Only heat the outside edge, not the top

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Railhead Clues

• Find the wire pass-through
• Wires solder to the outside edge, below the
  top of the railhead so trains wont derail
• A dab of hot glue holds the wire
• Only one wire needs to crossfor a track power
  connection
• (Only the white wire here)

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What else can I hack?

• Why tie up TrackPower Controllers topower many
  models?
• Make an adjustable-voltage power brick!
• Add a 2x2 power brick(now youve done it!)
• Stack a few modelson this same power

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What about Mindstorms Stuff?

• Ive only hacked with the RCX bricks.
• Ive seen some interesting sensors.
• I wanted to trigger train automation.
• I tried optical sensors, but they are
  bulky,take up space

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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

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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)

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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?

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Testing the magnet axis issue

• When trains are coupledthe reed switch shouldbe
  in-line with the track
• But, the first and last couplers usually pivot
  90 degrees!(The reed cannot sense them!)

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What is the best way?

• I built a fixture to try all three axis
• Adjustablepositioning
• Lights ifthe switchis tripped
• Heres the best axisto sense train couplers

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Building a Reed Switch sensor

• All it takes to build a basic switch
• LEGO 2x2 brickpower connector(cut a cable?)
• a pair of wires
• small reed switch(no polarity)
• A housing to keepthe reed safe

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Solder the reed switch

• Dont clip the leads of theswitch until you are
  done
• Keep the cable leadsshort, and solder themclose
  to the reed body
• Test the switch with a meter, or an RCX
• If it works, THEN you can clip the leads

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Build a safe enclosure

• The switch will fit inbetween the studs
• You need to trim 2studs for the wires!
• I use a thin router bit in the Dremel, but Ive
  also used an Xacto hobby knife too.
• Test-fit the switch before you proceed!

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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

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Uses for the Reed Switches

• Robot cows -gt
• Level crossing
• Train pacing(block control)
• Use a few in parallel, if it works
• Use a resistor plate to save inputs

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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

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Track Power Isolation

• Useful for Block Control of tracks
• Controlled by handor by Mindstorms!
• Original train pacing project developed by Tony
  Pratkanis, using all-LEGO part for a BayLUG
  public display

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How Block Isolation works

• Start with a normal loop of track,powered by a
  speed controller.
• Now, electrically isolate one sectionof track
  from the loop (the red track)
• When the train motor gets here, itstops because
  there is no power.
• Add a switch, so you can apply theloop power
  when you want it to go

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Step 1 Miniaturization!

• I replaced the LEGO switchand track power
  connectorswith a pair of Reed Relays
• I would drive them with anRCX, or a 9-volt
  battery box
• The reed relay is a reed switchwith a wire coil
  wrapped aroundthe reed switch.

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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 backfrom the track, andkept the
  profile low,below the trains

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Step 2 Make it simple!

• Short structure
• Self contained
• To isolate the block, just addpower.
• Fail-Safe
• No power? No isolation!

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Step 3 Make it reliable!

• I soldered to the outside ofthe railhead (away
  from theflanges 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

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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

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But how big is a Block?

• The white building hides the RCX
• The red tiles indicate the block limits

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Track Cleaning Tools

• Even a Kleenex is a light abrasive
• You will eventually wear off the metalon the
  railhead if you clean your track
• But track should be cleaned once in a while to
  preserve its service lifetime!

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L-Gauge Track Cleaning Cars

• Centerline was first, Aztec was second.
• Aztec bought Centerline, retired both!

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RCX Level Crossing Program

• Basic flow iswaiting for apassing trainto get
  near the crossing
• Start lights
• Lower gate
• Wait for train

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• Two of theprocess flows arepretty busy,moving
  thegates!
• Two othersdo nothing!

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Thank you for attending!

• Ive very glad that you came to BbtB
• Thanks for attending my talk
• You can reach me at
• zonker_at_baylug.org