Assembly for v2
Assembling the circuit board
Note: We chose the largest surface mount packages available for the parts of Pulse Pal 2, to simplify hand-assembly. However, this assembly procedure still requires you to solder two fine-pitch surface mount components which were not available in larger packages. By continuing this assembly procedure (or any assembly procedure on this wiki), you agree to the Sanworks terms and conditions. Most relevant to this guide, you assume full liability for any damaged components, lost time, lost data and personal injury.
Before assembly, ensure that you have all parts specified in the bill of materials in appropriate quantities.
ATTENTION! This guide, and the BOM, assume that you are using PCB version 2.1. Version 2.0 relies on parts that are out of production. Please note that the file name for board v2.1 is incorrectly denoted 0_8 in the repository, while the folder name is correct.
You will need:
1 soldering iron with a 1/32" conical tip (for through-hole parts)
Solder
Solder wick
A brass tip cleaner or a soldering sponge
A pair of non-magnetic, curved tweezers for placing surface mount components
A small Phillips head screwdriver (for 4-40 screws)
A 4-40 tap
Super glue
To solder the surface mount parts, you need
Either:
1 soldering iron with a very fine tip (e.g. Weller WXMP)
1 spool of fine solder (e.g. Loctite 796065)
Or:
1 rework station with a hot air gun (e.g. Xtronic 4040-XTS)
1 tube of solder paste (e.g. Chipquick SMD291SNL)
The latter method allows some components to self-align, as all of their pins will be exposed to molten solder simultaneously.
See this video for another example of assembly using hot air reflow.
This guide will assume you are using the first method, hand soldering with an iron. If you do not have experience with this method, we recommend watching this video, and gaining some experience with the techniques described in it.
First, we will add components to the printed circuit board. It looks like this:
Figure 1: The Pulse Pal r2 printed circuit board
Step 1: Add the DAC and microSD card socket
Required components:
BOM Part#18, AD5724 Digital to Analog Converter (DAC)
BOM Part# 13, MicroSD card socket
Instructions:
Solder the DAC onto the DAC footprint near the center of the board. Pay attention to the polarity symbol - a circular indentation on the part, which must align with the corresponding white polarity mark on the board. Both marks are illustrated in red below. A red rectangle was drawn around the DAC to help you find the correct location. Make sure that each leg is connected to the pad below with solder, and that no two adjacent legs or pads are bridged. If you make a solder bridge, you will have to remove it.
Next, solder the microSD card holder onto the microSD card footprint. Most microSD card sockets require reflow soldering, but this particular socket can be hacked - you can (carefully!) clip off the two metal tabs on the top, to expose the pins below.
The board should now appear as illustrated in Figure 2.
Figure 2: The PCB after adding the DAC and microSD card socket.
Congratulations, the hardest part is over!
Step 2: Add 22-ohm resistors
Required components:
BOM Part#16, 22-ohm resistor
Instructions:
Solder the resistors in the locations shown below. This soldering technique should be used for the next several steps.
The board should now appear as illustrated in Figure 3.
Figure 3: The PCB after adding 22-ohm resistors
Step 3: Add 1K-ohm resistors
Required components:
BOM Part#15, 1K-ohm resistor
Instructions:
Solder the resistors in the locations shown below (graphic shows 220-ohm, but your board should show 1K).
The board should now appear as illustrated in Figure 4.
Figure 4: The PCB after adding 220-ohm resistors
Step 4: Add 0.1ÎĽf capacitors (size 0805)
Required components:
BOM Part#21, 0.1-ÎĽf capacitor
Instructions:
Solder the capacitors in the locations shown below.
The board should now appear as illustrated in Figure 5.
Figure 5: The PCB after adding 0.1-microfarad capacitors
Step 5: Add 0.1ÎĽf, 4.7ÎĽf and 10ÎĽf capacitors (Size 1206)
Required components:
BOM Part#22, 4.7-ÎĽf capacitor (size 1206)
BOM Part#24, 10-ÎĽf capacitor (size 1206)
Instructions:
Solder the capacitors in the locations shown below.
The board should now appear as illustrated in Figure 6.
Figure 6: The PCB after adding 4.7 and 10-microfarad capacitors
Step 6: Add Ferrite Beads
Required components:
BOM Part#23, Ferrite Bead
Instructions:
Solder the ferrite beads in the locations shown below. Ferrite beads are magnetic, so ensure that you use non-magnetic tweezers to grip them while soldering.
The board should now appear as illustrated in Figure 7.
Figure 7: The PCB after adding ferrite beads
Step 7: Add LEDs
Required components:
BOM Part#12, blue LED
Instructions:
Solder the LEDs into the board. Polarity is indicated on the board with a + sign on the right pad (anode), and three dots on the left pad (cathode). The part has a polarity symbol on the bottom as shown:
When viewed from the top, the cathode side also has a tiny green dot (exaggerated in the illustration below).
The board should now appear as illustrated in Figure 7.
Figure 7: The PCB after adding blue LEDs
Step 8: Add the optoisolator and 3.3V regulator
Required components:
BOM Part#17, TLP2160 Optoisolator IC
BOM Part#20, LD1117S33CTR 3.3V regulator IC
Instructions:
Solder the two ICs as shown below. Pay attention to the polarity mark on the isolator IC (illustrated in red).
The board should now appear as illustrated in Figure 8.
Figure 8: The PCB after adding optoisolator and 3.3V regulator ICs
Step 9: Add the Arduino interface headers
Required components:
BOM Part#25, 2x6 male header
BOM Part#26, 1x8 male header
BOM Part#27, 1x6 male header
BOM Part#28, 1x4 male header
BOM Part#29, 2x3 female header
Instructions:
Optionally, you can use Arduino Due to make the alignment simpler. Remove Arduino Due from its box, and place it on a static-free soldering mat. Insert the long ends of the pins into Arduino Due, with the short ends poking upwards as shown:
Next, place the Pulse Pal board carefully onto the Arduino, allowing the pins to poke upwards through the matching holes. Press down firmly to make sure the board is levelled:
Then, solder all of the pins from above. You should not damage Arduino* if your iron is below 325C and the iron contacts the pad and pin for less than 2 seconds when making each solder joint. Be careful not to touch other components with the soldering iron.
Remove Arduino (if you used it). DO NOT CLIP THE LEGS OF THESE PINS! They are crucial for interfacing Arduino with the Pulse Pal circuit board.
* But you are 100% liable if you do. If you are worried about this, you can also add the pins without using Arduino to auto-align them.
Solder one junction on each pin header, then re-melt it as necessary to align the pins vertically. Then solder the remaining pins.
The board should now appear as illustrated in Figure 9.
Figure 9: The PCB after adding Arduino Headers
Step 10: Add the oLED screen headers and DC converter
Required components:
BOM Part#34, 8-pin female strip header
BOM Part#19, +5V to +/-12V DC converter, CC3-0512DF-E
Instructions:
Press the two female strip headers into the 16-position row of holes in the top-left corner of the board. Make sure they are 90 degrees with respect to the board surface. Solder them into place from the bottom side of the board, and clip off the legs with a wire cutter.
Solder the DC converter to the board. You can use the back side of your tweezers as a wedge to stabilize the board while soldering.
The board should now appear as illustrated in Figure 10.
Figure 10: The PCB after adding oLED Headers and the DC power supply
Step 11: Add the thumb joystick, BNC connectors and oLED screen standoffs
Required components:
BOM Part#33, thumb joystick
BOM Part#2, BNC connector
BOM Part#4, nylon standoff, M-F, 0.5"
BOM Part#11, 4-40 hex nut
BOM Part#6, aluminum standoff, F-F, 0.625"
Instructions:
Align the joystick pins with the matching holes in the board. You may need to bend them slightly.
Press the joystick fully into place, and solder all of its pins.
Solder the middle pin of each BNC connector.
Hold the board up, and re-melt the middle pin, while pressing the BNC connector against the board. This ensures that it is well seated.
Solder the remaining BNC connector pins.
Two 0.5" stand-offs will be added in the locations shown below. Screw the lower stand-off into a 4-40 hex nut on the back-side of the board. Screw the upper stand-off into the aluminum stand-off.
The board should now appear as illustrated in Figure 11.
Figure 11: The PCB after adding thumb joystick, BNC connectors and oLED standoffs
Step 12: Add the oLED display and microSD card
Required components:
BOM Part#1, oLED display
BOM Part#10, 1 x 16 male strip header
BOM Part#4, nylon standoff, M-F, 0.5"
BOM Part#6, aluminum standoff, F-F, 0.625"
BOM Part#9, 1.6mm spacer
BOM Part#7, 4-40 screw, 1/4" length
BOM Part#38, microSD card
Instructions:
Insert the microSD card into the microSD card socket. The socket is spring loaded, so press in to release the card if necessary at a later time.
Carefully tap the mounting holes of the oLED display with a 4-40 tap.
Insert the short-pinned side of the 1 x 16 header into the oLED board from below.
Ensure the pins are pointing downwards 90 degrees with respect to the board, and solder from above.
The oLED display should now look like this:
Next, make a standoff stack: screw the male side of the 0.5" standoff through the 1.6mm spacer, and into the 0.625" standoff.
Screw the standoff-stack from the previous step into the upper-left mounting hole of the oLED display, using a 1/4" 4-40 screw. The screw should come through the oLED board from above, and screw into the 0.5" standoff below:
Insert the 16-pin connector into the Pulse Pal board, ensuring that the oLED display's right side rests evenly on the two standoffs. If the display is even, the gold pins on the left should be slightly visible (i.e. not 100% plugged in).
Screw the right side of the oLED into the stand-offs on the Pulse Pal board.
The board should now appear as illustrated in Figure 12.
Figure 12: The PCB after adding oLED display
Step 12: Add the Arduino Due microcontroller and remaining stand-offs
Required components:
BOM Part#5, nylon standoff, M-F, 0.625"
BOM Part#6, aluminum standoff, F-F, 0.625"
BOM Part#32, Arduino Due microcontroller board
Instructions:
Plug the Arduino board into the back side of the Pulse Pal board.
In each of the three corner-holes, screw a nylon M-F standoff below the board into an aluminum F-F standoff above the board.
Congratulations, you have completed the circuit board assembly!
Next, test the board with an oscilloscope, and fix any soldering errors before adding the enclosure.
Assembling the enclosure
Note: illustrations for this section are not yet available. You can follow the text below, and see the v1.X assembly illustrations for now. There are 2 differences from v1.X:
1. You have to encase the light pipes with heat shrink tubing for Pulse Pal 2, to block neighboring LEDs.
Make sure the bottom face of the light pipe remains exposed.
2. The 4 screws to secure the bottom panel are omitted.
Before assembly, ensure that you have all 7 components of the laser cut enclosure. Remove paper masking from the acrylic.
If you cut the enclosure from "Brushed Aluminum Top, Black Core" acrylic, the edges may have a black residue from the laser. Clean the edges with ethanol-moistened paper towel.
First, ensure you have all 7 panels. Place Pulse Pal on the rear panel as shown:
Figure 13: The pulse pal enclosure parts.
Step 1: Add light pipes to enclosure face
Required components:
BOM Part#3, light pipe
BOM Part#31, heat shrink tubing
Instructions:
Press each light pipe fully into the light holes as indicated below. A firm press will be necessary, so that the rear lip the light pipe head is flush with the enclosure surface.
Turn the face plate around, and add a *small* drop of krazy glue to the back side of each pipe where it joins the enclosure, to secure them in place.
Wait 15 minutes for the glue to dry.
Cut 6 [?]mm segments of heat shrink tubing.
Place a heat shrink segment over each light pipe, ensuring that the tubing is even with the bottom of the pipe.
Use a heat-gun on "low" to shrink the tubing. This will block light from adjacent indicator LEDs.
The light pipe and light holes are illustrated in Figure 14.
Figure 14: Light pipe placement.
Step 2: Secure the circuit board to the rear enclosure panel.
Required components:
BOM Part#7, 4-40 screw (1/4")
Instructions:
Using 5 1/4" 4-40 screws, secure the circuit board to the rear enclosure panel.
The screw holes are identified in Figure 15.
Figure 15: Rear panel screw placement.
Step 3: Add enclosure bottom and sides.
Required components:
None
Instructions:
Stand the bottom and side panels on the enclosure rear as shown in Figure 16.
Figure 16: Addition of side panels.
Step 4: Add the enclosure face panel
Required components:
BOM Part#7, 4-40 screw, 1/2" length
Instructions:
Remove the plastic protector from the oLED screen if you have not already done so
Place the enclosure face panel on the front of the device. Ensure that all tabs from the bottom and side panels snugly fit through rectangular holes in the face panel. Ensure that the oLED screen is flush with the front face of the enclosure face panel.
Screw the face panel in place with 1/2" 4-40 screws.
The appropriate screw holes are illustrated in Figure 17.
Figure 17: Addition of the face panel
Step 5: Add the enclosure top panel
Required components:
BOM Part#7, 4-40 screw, 1/2" length
BOM Part#11, 4-40 nut
Instructions:
Place the enclosure top panel on the top of the device. Ensure that all tabs from the back and face panels snugly fit through rectangular holes in the top panel.
Screw the top panel in place with 1/2" 4-40 screws. For the top two screws, hold the nut in the T-slot securely with your pinched fingertips while adding the screw.
The appropriate screw holes are illustrated in Figure 18.
Figure 18: Addition of the top panel.
Step 6: Add the rack mount wing
Required components:
BOM Part#7, 4-40 screw, 1/2" length
BOM Part#11, 4-40 nut
Instructions:
Place the rack mount wing behind the front panel, aligning the two clusters of three screw holes with corresponding holes in the face panel.
Screw the rack mount wing into the face panel with 1/2" 4-40 screws, placing 4-40 nuts behind the wing.
The appropriate screw holes are illustrated in Figure 19.
Figure 19: Adding the rack mount wing
Congratulations, you have assembled a second-generation Pulse Pal!