FabLab PHABLABS 4.0 Laser Labyrinth User manual

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Photonics Workshop
Laser Labyrinth

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excluded.
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with the information or from your use of it is excluded.
This instruction is published under the Creative Commons license CC-BY-NC

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PROPOERTIES OF THIS WORKSHOP
PHOTONICS WORKSHOP LASER LABYRINTH (FOR INSTRUCTORS)
SUMMARY
The ‘laser labyrinth’ is a logic maze game that teaches STEM skills. The game
requires you to use mirrors, beam-splitters and brainpower to direct the laser
through a series of mind-challenging mazes and light up the target. In this
workshop the participants will build a version of the laser labyrinth and of course
test it in the end. Thus, the workshop focuses on the construction of the game
and on the handling of lasers and mirrors.
TARGET AUDIENCE:
Youngsters: 10-14 years
MAX.PARTICIPANTS:
The workshops is most suitable for a group of around 8-10 participants. If you
want to perform the workshop with a bigger group e.g. of 18 participants, 5
instructors would be necessary. Further, the workshop would take up to 1 hour
longer. The workshop duration also depends on the soldering experience of the
participants. If they don’t know how to solder, they need a special introduction
and attention.
SUGGESTED TIME PLANNING:
In total about 4 hours (depending on how long you keep the introduction part at
the beginning of the project and playing part at the end of the project.
TIMING
IN MINUTES
ACTIVITY
0-20
Welcome group: Give a short introduction of the laser labyrinth
and its theoretical background (law of reflection)
20-45
Step 1: Assembling of the game board
45-120
Step 2: Assembling of the starting figure and target
120 - 200
Step 3-8: Construction of the remaining playing pieces
200-230
Play your own built laser labyrinth and experiment with the laser
reflection
230-240
Closing summary, feedback,..

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BACKGROUND
Laser
What do a CD player, a laser printer and a bar code scanner have in common?
Exactly - in all these devices a laser is used. Lasers are an essential part of our day-to-day life
and are used in many different devices and places, especially in the industry or in medical
devices. In this workshop we will together built the game ‘laser labyrinth’ where one important
component is of course a laser.
What is a laser?
A laser is a machine that makes an amplified, single-colour source of light. The beam of light
from the laser does not get wider or weaker as most sources of light do. It uses special gases or
crystals to make the light with only a single color. The gases are energized to make them emit
light. Then, mirrors are used to amplify (make stronger) the light and to make all the light travel
in one direction, so it stays as a narrow beam of collimated light.
When pointed at something, this narrow beam makes a single point of light. The energy of the
light stays in that one narrow beam instead of spreading out like a flashlight (electric torch).
The word "laser" is an acronym for "light amplification by stimulated emission of radiation".
(source: https://simple.wikipedia.org/wiki/Laser)
The law of reflection
The most important principle the ‘laser labyrinth’ is based on is the law of reflection. Light
reflection in general is very important because it is the reason why we can see anything at all.
When a ray of light strikes a medium some of the ray will bounce off the surface. The way the
light will be reflected is depending on the surface the light is bouncing off. (The law of reflection:
http://www.physicsclassroom.com/mmedia/optics/lr.cfm).
According to the law of reflection it is possible to predict, how the light ray will be reflected off
the mirror. The law of reflection defines, that the angle of the incident light ray is equal to the
angle of the reflected light ray.

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The figure above illustrates this principle: The ray of light approaching the mirror is known as the
incident ray. When the incident ray strikes the mirror, it will bounce off the mirror. The ray of light
that leaves the mirror is known as the reflected ray. The normal line divides the angle between
the incident ray and the reflected ray into two equal angles. These angles are always measured
from the normal, not from the mirror. The incident ray, the normal at the point of incidence and
the reflected ray, all lie in the same plane (Law of reflection;
http://farside.ph.utexas.edu/teaching/302l/lectures/node127.html )
ABOUT THE GAME:LASER LABYRINTH AND ITS COMPONENTS
The game requires you to use mirrors, beam-splitters and brainpower to direct a laser beam
through a series of mind-challenging mazes and in the end light up a target.
The game board
The form of the game board is a hexagon, which consists of hexagonal cells.
The playing pieces of the game have a hexagonal shape as well, since they
have to be inserted into the hexagonal cells.
Due to the hexagonal form of the game board cells, the playing pieces can
be inserted in six different directions. This offers more challenging
possibilities to direct the laser beam through the labyrinth, than a square
game board.
Playing piece Guide:
In total the game laser labyrinth consists of 12 hexagonal playing pieces.
Playing piece
function
components
1x Starting Figure
Provides the laser beam. Push the
button at the side wall of this playing
piece to engage the beam.

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1x Target
Receives the laser (the goal of the
game is to direct the laser beam
through the labyrinth in order to hit the
target)
6x Mirror
Reflects the laser. The 6 playing
pieces differ in the angle, the laser
beam can pass through.
2x Beam Splitter
Splits the beam into two paths. One
path is reflected 90 degrees and the
other path passes straight through the
playing piece
2x Direction
Blocker
The laser beam can only pass through
a limited number of the six possible
directions. There is one playing piece,
that lets the laser beam pass through
two sides and another one letting the
playing piece pass through four sides
of the playing piece.
Direction Blocker I:

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Direction Blocker II:
The most important playing piece of the laser labyrinth is the starting figure
providing the laser beam. By pushing the button, inserted into one side wall of
the playing piece, the laser beam is engaged.
Another important playing piece is the target, which the laser beam has to hit. In
order to light up the target you have to arrange the other playing pieces, such as
beam splitters or mirrors, in a specific way onto the game board.
For more advanced players: The game will be more challenging with blockers inserted into the
hexagonal cells of the game board, as this type of playing piece prevents the placement of any
playing piece in that particular cell. Using these different playing pieces opens a big variety in
directing the laser through the labyrinth and to the target in the end. However, in this version of
the game blockers are not included.
The hexagonal form of the playing pieces make it even more challenging to direct the laser
beam. A good dose of brain power and an understanding of science are necessary in order to
hit the target. The law of reflection states that the angle of the incident ray hitting the mirror is
equal to the angle of reflection. Applied to a hexagon, a laser beam will always hit the hexagon’s
side perpendicularly. If this principle will be used cleverly, the mirror can be positioned in a way,
that the laser beam will pass through a specific side.
More specifically: with only two different mirror
positions the laser beam will be deflected on one of
the four sides. In figure 9 the incident ray enters the
hexagon through side 1 and depending on the
position of the mirror, passes through side 2 or 3. By
turning the playing piece it is possible to let the
beam pass through side 5 or 6. Without a reflection
of the mirror the beam would pass through side 4.

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Safety
A game with lasers? Is that safe for kids? In this case yes, because several safety measures
have been made. Most importantly: so called “eye safe” lasers will be used as laser diodes. In
order to create additional safety, the game figures are only supplied with power when they are
inserted into the playing cells, thanks to a reed switch integrated in the starting figure. A reed-
switch is an electrical switch operated by an applied magnetic field. Thus, in some cells of the
game board magnets are inserted. The laser will only be supplied with electricity, when the
starting figure with the reed-switch is inserted onto a playing cell with a magnet.
Additionally, every figure and the game board are surrounded by side walls. Moreover, the laser
beam can only emerge at certain openings on the side walls preventing from looking into the
laser accidentally. We recommend the game to kids aged 10 years and above.
Make sure to give safety instructions, when handing out the laser and especially point out not to
look into the laser or point the laser into one’s eye, since in can cause bad eye injuries.

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PART LIST
Photonics parts:
part
quantity
Eye safe laser diode
1
Electronic parts:
part
quantity
Cable red/black/yellow/blue
10 cm each
tactile switch 6x6mm, height: 7,0mm
1
Reed switch ø 2,2m
1
Lithium button cell battery, 3 Volt, 210 mAh,
20.0x3.2 mm
2
Button cell holder, vertical, PCB version
1
Other parts:
part
quantity
self-adhesive mosaic mirror 10x10mm²
6 pieces
mirror foil semitransperent
Each set requires two pieces of 2x1cm² foil.
block magnet 3 mm³
6
Other parts –standard available in Fablab
part
quantity
wood glue
glue sticks for hot melt glue gun
rubber bands
(not necessarily, helps holding the playing
pieces together, when assembling them)
tin solder
Cable red/black
adhesive tape
wood panel 1200x600x3mm³
for Laser cutting the material

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screws
2
nuts
2
Tools
Laser Cutter
3D printer
Table saw (or something similar in order to cut the mirrors)
Hot melt glue gun
Soldering iron and solder
Diagonal pliers, possibly wire stripper
Rubber mallet (optional)
Wood glue
burn ointment (just in case and to be prepared if a kid get burns with the soldering iron)

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PREPARATIONS:
CUT OUT THE DIFFERENT PARTS OF THE GAME WITH ALASER CUTTER
Please note: Cutting the individual game components with the laser cutter takes about 20
minutes for one set. Therefore, it is strongly recommended to cut out all the components for the
workshop participants before the workshop. To demonstrate the laser cutter, it is recommended
to cut a set of one game at the beginning of the workshop, which can then be used for another
workshop.
Overview of the laser labyrinth parts for one set:
Please note: In order to save time during the workshop, we recommend to prepare little bags,
in which the components for one specific playing piece are already inserted. Thus, the
participants won’t have to look for the single components, before assembling the playing pieces

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together. The corresponding components of the different playing pieces are described in the
instructions below and in the playing piece guide on page 5-7.
3D PRINT A SIDE WALL FOR THE STARTING FIGURE
For the Starting figure a 3D printed side wall is needed. Print these side walls according to the
details provided to you online.
FURTHER PREPARATIONS TO BE MADE:
Besides cutting out the playing pieces and game board with the laser cutter and pack little sets
containing the different parts for each playing piece, it is advised, to prepare a few more steps,
in order to guarantee a smooth course of the workshop and to minimise sources of errors.
a) cut off 4 different cables + 2 for the laser diode (ideally one red and one blue) (length
approx.: 10cm)
b) solder cables onto the laser diode (blue cable onto the –pole of the laser diode/red cable
onto the + pole of the laser diode)
c) glue together the two parts of the battery holder (otherwise it won’t fit
into the starting figure)
d) cut out a square of the mirror foil semitransparent, so that it will cover
the hole of the wood panel.
For all preparation steps around 5 hours should be planned, if material for 15 participants is
prepared, since only the laser cutting time is around 5 hours (laser cutting time for 1
game=20 minutes)

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CONSTRUCTION OF THE GAME BOARD AND THE PLAYING PIECES
STEP 1: BUILDING THE GAME BOARD
The game board consists of 2 layers and will be surrounded by six side walls. The lower field
layer is a hexagon, the upper field layer is a grid of several cut out hexagons. The sidewalls of
the playing field are mainly used for safety reasons when dealing with the laser.
1.1: First, the upper playing field layer (with hexagonal recesses) is glued onto the floor (without
recesses) with wood glue. Spread the wood glue drop by drop onto the top layer of the playing
field. When sticking together both parts, make sure that both layers are accurately adhered to
each other. Make sure, that the holes on the edge of both layers (see marked in red below) lie
directly above each other, so that in the next step, the side walls can be inserted into it.
1.2: If there is wood glue swelling out at the hexagonal recesses, it can be wiped away with a
damp Zewa cloth or a cable tie.
1.3: In a next step, insert the side walls from above into the holes at the edge of the playing
field. Two sidewalls have an engraving, that can be placed either outward or inward. If inserting
the sidewalls is a bit difficult, you can help with a rubber hammer to fix them into the game
board. Use the rubber hammer very carefully and easily hit on the side walls, so that they do not
break.

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1.4: After all walls have been inserted into the ground layer of the game board, the gaps
between the side walls should be glued together from the outside with wood glue, to make them
more stable. After the wood glue has dried in the corners, a masking tape can be glued around
the side walls for additional stabilization. At the end of the workshop, Tte masking tape can be
untacked again
The game board is now put together completely. The only components missing to finish the
game board are magnets that need to be inserted into the square holes that are engraved in
some of the hexagonal cells. Please make sure, for safety reasons to hand out the magnets to
the participants at the end of the workshop. A reed switch on the bottom of the starting block
will trigger the laser only when it is placed on a magnet. To prevent the children from carelessly
handling the laser at the beginning of the workshop, the magnets should be handed out after the
remaining figures have been completed at the very end of the workshop.
Regarding the order of which playing piece should be put together first: We recommend to start
with the target and starting block. The starting block is the most complex figure, since the laser
needs to be inserted and the electronics parts soldered together. Moreover, the starting block is
the most important figure of the game. Since, it might be too difficult to begin with the
construction of the starting figure, we recommend starting with putting together the target figure
in order to explain the principle of building the playing pieces.
Another reason to assemble the target and starting figure first, is the possible a lack of time. For
the starting figure, soldering work is required and it may be beneficial to do this work as long as
the participants are still fit and concentrated. The steps of putting together the other figures, is
almost the same for each of them. In case there is a lack of time at the end of the workshop and
not all the participants have finished all their figures, they could finish putting together the
figures at home as well –with the help of the instructions.

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STEP 2: ASSEMBLING THE STARTING FIGURE AND TARGET
It’s recommended to put together the target block first, since it is more easy and quickly put
together than the starting block.
Components of the target figure: 6 long side walls with hole |one bottom | one cover marked
with checkered flag
2.1: Take a side wall and fill the holes of the side walls with hot glue. Thus, the laser light will be
reflected diffusely when it hits the target figure correctly and it is clearer to see whether the laser
beam hits the target figure or not. When filling the hole with hot glue, make sure that the side on
which an i(marked in red below) is printed on, is facing up. In order to prevent the side walls
from sticking on the table, place a foil onto the table, when filling them with hot glue.
2.2: Once the hot glue in the side walls has dried, the single components of
the target figure can be put together. The side walls must be attached to the
bottom in such a way that the “i” points down towards the floor, regardless
of whether the i points to the outside or to the inside of the playing piece. It
is best to put a side wall into the bottom plate first. Then place the cover
(with the checkered flag up) onto the side wall and then insert a opposite
side wall onto the bottom and cover. When fixing the remaining side walls, it
is recommended that opposite sides are always attached one after the
other. This will stabilise the playing piece best, while assembling the single

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parts.
General note on assembling the playing pieces (applies to all playing pieces):
After each side wall has been put together to the bottom and cover of the figure, the corners of
the side walls can be glued together with wood glue making the figures more stable. Remaining
wood glue on the side corners can be blurred with either a finger or a damp paper towel. The
sides of the wood parts marked with an | always have to face inside of the figure.
Additionally, a rubber band can be wrapped around the playing pieces, to make sure that they
really keep sticked together.
After the target has been put together, the starting figure should be assembled. This step will
take up to 60 minutes. What is most time consuming is soldering the electronics and further, the
exact alignment of the laser diode. Depending on the soldering experience of the participants
and the number of soldering places, assembling the starting figure can take some more time or
waiting time for the participants. Please consider this for your workshop planning.
2.3: Assembling the starting figure:
Components of the starting figure: 3 side walls made out of wood | 1 side wall made out of
wood with a small hole | 1 side wall with a cut out square | 1 3D printed side wall| 1 bottom
bottom with a slot | 1cover (only frame) | 1 cover with a cut out square hole

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In addition to the wooden parts, electronics parts are required for the starting figure: laser diode
|battery holder | switch | magnetic switch| cable |two 3V button cells
2.4: Soldering of the electronic parts:
Before soldering, the participants should be asked, if they have already soldered and how
experienced they are. Even if the participants have a lot of soldering experience, the principle of
soldering should be explained with an easy example, to make sure that everyone is more or
less on the same level.
safety instructions soldering:
The temperature of the hot soldering iron is above 300 °C (this is three times hotter, as really really
hot water). Incorrect handling can cause burns! The following notes have to be considered carefully:
Carefully lay all power cables on the table so that they can not be damaged by the soldering iron.
Work on a heat-resistant surface, making sure that there are no flammable objects (such as plastics, wood, etc.)
around you.
Only remove the soldering iron from the holder when everything is ready for soldering.
Always hold the soldering iron over the table, only solder it over the work board.
Work in a well ventilated area and use a fume extractor. Do not inhale fumes from the soldering processes.
Use a third hand, a circuit board vice, pliers, tweezers, or clamps for holding components to avoid burns.
Do not have food or drink near the working area. The solder is usually a tin/lead alloy and lead is toxic. The flux is a
chemical used to help metal parts soldered together. It is acidic and toxic. Clean up spilled flux immediately. Wash
hands after soldering. Flux can cause acid burns to the skin or damage clothing. In case of acid burns, flush imme-
diately with water.
Always return the soldering iron to its stand when not in use. Never put it down on your workbench. The soldering
iron tip is very hot (about 400°C). Avoid touching plastic, wire insulator, or any flammable material in the working ar-
ea with the soldering iron.
Turn the soldering station to standby or off if not used for more than few minutes. Turn unit off or unplug it when do-
ne.
Dripping solder is very dangerous –even on clothes
More information: http://www.riccardobevilacqua.com/SolderingSafety.pdf

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Soldering the electronic parts of the starting figure:
Solder the individual parts according to the following order:
Yellow cable reed switch yellow cablebuttonyellow cable 
Battery holder - pole blue cable reed switch blue cable laser
diode –pole red cable laser diode + pole red cable battery
holder + pole
You can find a more detailed step-by-step explanation below:
First, take the resistor and bent the legs of it a little bit. Next, solder the yellow cable onto
one leg of the resistor.
Then, solder onto the yellow cable’s end the button. In this step it doesn’t matter on which
of the four legs the yellow cable is soldered to.
However, it is important that in the next step, the yellow cable is soldered to the diagonally
opposite leg.
Solder this second yellow cable, onto the –pole of the battery holder.
Solder the reed contact (soldered together already on the yellow cable) onto the blue cable.
Now laser diode will be connected. Take the end of the blue cable and solder it onto the –
pole of the laser diode.
The plus pole of the laser diode will be soldered onto the red cable.
One missing connection lies between the + pole of the battery holder and the red cable,
connected to the +pole of the laser diode. Connect the red cable fixed on the laser diode
onto the + pole of the battery holder.
The electronic components of the starting figure should look like this now:
2.5:After the electronics have been soldered together, these components need to be
surrounded by the side walls, cover and base plate. Take the cover plate (with a square hole)

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and place all electronic components through this hole, except the button cell holder which needs
to be placed outside of the playing piece. Once the button cell holder sits on the cover plate, we
can continue with fixing the reed switch into the bottom plate.
2.6:The reed switch needs to be fixed onto the slot of the bottom. With a little bit of hot glue, the
reed switch can be attached to the hole on the floor.
2.7: Next, the button which fires the laser beam should be placed through the square hole,
found on one of the sidewalls. The button must be operated easily from the outside, so be
careful, when inserting the button through the square slot. Make sure, that the button is not
stuck inside of the figure. Pliers can be helpful to pull out the button, if it is stuck too much
inside. If the button sits well, it can be fixed using the hot glue gun.
2.8: Next, the laser diode is inserted into the hole of the 3D printed sidewall. Place the laser
diode through the hole of the 3D printed wall as wide as possible. Place the side wall onto the
bottom and cover plate and repeat this step with the wooden side wall containing the button. is
inserted onto the bottom plate on the opposite side of the just inserted wooden side wall.

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2.9: Insert the two nuts into the corresponding fixture of the 3D printed wall (marked with red
squares in the image below). Insert the tow screws into the nuts. One screw is inserted through
the hole of the side wall and the other screw is inserted through the open cover plate. This
mechanism will help you to adjust the direction of your laser diode.
The remaining side panels shall be tacked together, once all the electronics have been inserted
into the starting block.
The starting figure together with the soldering of the electronics is now completed. To operate
the laser diode, insert the batteries into the battery holder.
In a next step, the alignment of the laser diode, needs to be adjusted, to guarantee, that the
laser beam optimally meets the target figure.
We recommend distributing the batteries and thus, aligning the laser diode at the end of the
workshop. This will prevent the participants from playing with the laser before finishing all other
steps of the workshop. Another safety step is to distribute the magnets at the end of the
workshop as well. The magnets need to be inserted into the corresponding holes in the game
board. Only with the magnets inserted in the fields, the laser beam will be triggered through the
reed switch.
We will continue now with assembling the other playing pieces. At the end of the workshop, we
will align the laser diode. This step will take around 8 minutes per participant. If you are short on
time at this stage of the workshop, we recommend starting with the alignment of the laser diode
now. If you first undertake the alignment of the laser diode, before finalising the other steps,
make sure to recollect the distributed magnets and cell batteries.