Part 1: Assemble optical components

a) Solder the LEDs

1. For each LED, cut about 60 cm (2 ft.) of red stranded wire, and the same length of black stranded wire.
2. Twist, tape, or heatshrink each pair of wires together.
3. Strip about 5 mm (1/4 in.) of insulation from the end of each wire
4. Solder the red wire to the positive terminal of the LED PCB and the black wire to the negative terminal. Heat will flow from the solder pad into the metal core PCB so you may have to increase the temperature of your soldering iron or wait for the pad to get hot enough for the solder to flow.
5. Gently flex and test the wire to make sure the solder joints are secure. If the joint is going to fail, you want it to fail now, before it’s bonded to the heatsink!
6. Repeat for each LED

b) Test the LEDs

1. If you haven’t already, strip about 5 mm (1/4 inch) of insulation from the end of the wires opposite the LEDs.
2. Cut 6, 5 cm (2 in.) pieces of solid core wire and strip 5 mm of insulation from all of the ends
3. Solder 1 piece of solid core wire to each stranded wire
4. Pull on the two wires to make sure they are securely bonded together
5. Cut 6, 3 cm (1 in.) lengths of heat shrink tubing
6. Slide heat shrink tubing onto each wire such that the solder joint is centered
7. Apply heat to shrink the tubing
8. Attach the 12 V supply to the positive and negative rails of the solderless breadboard
9. Plug in the 12 V power supply and attach the plug to wire converter
10. Insert one LED driver onto the breadboard
11. Connect the VIN+ and VIN- terminals of the driver to the positive and negative rails using pieces of solid core wire
12. Connect the red wire from the led to the LED(+) terminal and the black wire to the LED(-) terminal of the driver
13. At this point your LED should light up. The IR LEDs may be dim or invisible to the naked eye. These wavelengths will show up purple on cell phone cameras which can be used to verify the LEDs are working.
    WARNING! DO NOT LEAVE THE LEDs ON FOR EXTENDED PERIODS OF TIME. THEY WILL OVERHEAT! Only leave them powered long enough to verify that they are working.
14. Repeat for the other 2 LEDs

c) Epoxy LEDs to heatsinks

1. WARNING! Attaching the LEDs to the heatsinks is a permanent process.
2. Prepare your workspace with the 3 LEDs, the 3 heatsinks, and 6, #8-80 cap screws
3. On a scrap piece of cardboard combine the thermal epoxy according to the instructions on the package
4. Spread a thin layer of epoxy on the back of the LED PCBs
5. Place the LED on the heatsink and align the mounting holes
6. Attach the LED using 2 #0-80 cap screws
7. Repeat for the other 2 LEDs
8. Allow epoxy to cure for 4-8 hours

d) Mount DMD

1. Using a saw, cut approximately 45 mm (1.75 in.) piece off of the Delrin bar
2. Draw a line square across the face about 20 mm (0.75 in.) from the edge
3. Place the DMD PCB such that the drawn line intersects the mounting holes
4. Roughly center the DMD on the piece of Delrin
5. Using a nail, or punch, carefully mark the center point of the mounting holes where they intersect with the drawn line
6. Drill two 1.75 mm (1/16 or 5/64 in.) holes through the Delrin at the marked points
7. Use two #2-56 capscrews to screw the DMD PCB to the Delrin.
   Note: The back of the PCB is not flat so don’t over tighten the cap screws. The goal is to have the face of the DMD parallel to the face of the Delrin block. Tightening too far will tip the DMD upward and cause no end of trouble.
8. Loosen the set screws and remove the top arm of the DMD mount (KM100C)
9. Remove the screws from the top of the rods and then attach the two 1.5″ (ER1.5) rods to extend the DMD mount
10. Set the Delrin against the bottom arm and lower the top arm until it grabs the top of the Delrin
11. Push the Delrin/DMD assembly forward against the stops on the arm
12. Tighten the top arm set screws
13. Attach the assembled mount to a 4″ post using an 8-32 capscrew.
14. Insert the post into a 4″ post holder, attach a baseplate to the bottom of the holder and set the assembly aside.

e) Mount collimating lenses

Always use gloves when handling optics

1. Unscrew the retaining ring from the an LMR1 lens holder
2. Place a 20 mm aspheric collimating lens into the lens holder such that the flat side of the lens is flush with the internal ridge.
3. Tighten the retaining ring.
4. Screw a TR4 post into the #8-32 mounting hole on the bottom of the lens holder
5. Attach a baseplate (BA1S) to a post holder (PH4) using a 5/8″ long 1/4-20 capscrew
6. Insert the TR4 post with lens holder into the post holder and set aside
7. Repeat for the other 2 collimating lenses

f) Mount dichroic mirrors

The dichroic mirrors from Edmund optics are very thin so use care when handling them.

Parts needed:

• 2x dichroic mirrors (69-206, 69-208)
• 2x adjustable lens mount (LH1)
• 2x 4″ post (TR4)
• 2x 4″ post holder (PH4)
• 2x Post holder bases (BA1S)
• 2x 5/8″ long 1/4-20 cap screws

1. Place the adjustable lens holder face up on a flat surface
2. Loosen the three set screws on the arms to allow them to move freely
3. Insert the dichroic into the notch of one of the arms and, while supporting it from the bottom, move the three arms inward such that the mirror is gripped. Note: the mirror does not need to be exactly centered in the mount, but it’s critical that the face of the mirror is parallel with the face of the mount.
4. Tighten down the set screws so the arms won’t move
5. Make sure the mirror is securely held and won’t fall out when the lens holder is shifted to a vertical orientation. If it’s loose move one or more of the arms more toward the center to tighten the grip on the mirror
6. Screw a TR4 post into the #8-32 mounting hole on the bottom of the lens holder
7. Attach a baseplate (BA1S) to a post holder (PH4) using a 5/8″ long 1/4-20 capscrew
8. Insert the TR4 post with lens holder into the post holder and set aside
9. Repeat for the other lens holder and dichroic mirror

g) Mount polarizers

Parts needed:

• 2x linear polarizers (LPNIRE100-B)
• 1x rotation mount (RSP1)
• 1x mirror mount (FMP1)
• 1x 6″ post (TR6)
• 1x 4″ post (TR4)
• 1x 4″ post holder (PH4)
• 1x Post holder base (BA1S)
• 1x 5/8″ long 1/4-20 cap screw

1. Loosen the set screw on the fixed mirror mount
2. Place 1 of the polarizers in the mount
3. Tighten set screw
4. Screw a 6 inch post into the #8-32 mounting hole on the bottom of the mount
5. Remove the retaining ring from the rotation mount
6. Place the second linear polarizer into the mount
7. Tighten the retaining ring
8. Screw a 4 inch post into the #8-32 mounting hole on the bottom of the mount
9. Attach a baseplate (BA1S) to a post holder (PH4) using a 5/8″ long 1/4-20 capscrew
10. Insert the TR4 post with lens holder into the post holder and set aside

h) Mount achromatic lens

Parts needed:

• 1x 50 mm achromatic lens (AC254-050-B)
• 1x Clear edge lens mount (PFM1)
• 1x 4″ post (TR4)
• 1x 4″ post holder (PH4)
• 1x Post holder bases (BA1S)
• 1x 5/8″ long 1/4-20 cap screws

1. Loosen the set screw on the clear-edge mount
2. Place the lens in the mount such that the flat side is in contact with the retaining ridge
3. Tighten the setscrew to secure the lens
4. Screw a 4 inch post into the #8-32 mounting hole on the bottom of the mount
5. Attach a baseplate (BA1S) to a post holder (PH4) using a 5/8″ long 1/4-20 capscrew
6. Insert the TR4 post with lens holder into the post holder and set aside

i) Mount the LED assemblies

Parts needed:

• 3x LED assemblies from step 1c
• 6x 1″ long posts (TR1)
• 3x 6″ long posts (TR6)
• 6x Right angle clamps (RA90)
• 3x 4″ post holders (PH4)
• 3x Post holder bases (BA1S)
• 3x 5/8″ long 1/4-20 cap screws
• 6x 1″ long 1/4-20 cap screws

1. Attach 3 baseplates (BA1S) to 3 post holders (PH4) using 3 5/8″ long 1/4-20 cap screw
2. Insert the TR6 posts into the post holders
3. Slide two right angle clamps over each 6″ post
4. Slide the 1.25″ long cap screws into two outer mounting holes of the heat sink
5. Screw the heatsink onto the 1″ posts
6. Slide the 1″ posts into the other aperture of the right angle clamps
7. Tighten everything so it won’t slide around. The height of all the components will be set in future steps so setting it here isn’t critical

On to Part 2: Mapping Optical Paths