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 thenon-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 oftrack, that 5-inchstraight track isa 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, quicksoldering!

• 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 thejoints of their track

• You should also brace your joints!

• AFTER soldering.

• If you don’t, your joints may bend underpressure 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 thegauge, andtop 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 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!

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 twopieces in the end… --->

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…

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 crossfor a track power connection

• (Only the white wire here…)

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 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 coupledthe reed switch shouldbe 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 switchis tripped

• Here’s the best axisto 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 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

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 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 handor 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 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 switch

with a wire coil wrapped aroundthe 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 backfrom the track, andkept the profile low,below the trains…

Step 2: Make it simple!

• Short structure

• Self contained– To isolate the

block, just addpower.

• Fail-Safe– No power?

No isolation!

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…

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 metalon 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 iswaiting for apassing trainto get near the crossing– Start lights– Lower gate– Wait for train

• Two of theprocess flows arepretty busy,moving thegates!

• Two othersdo 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