Lockbox Assembly Guide

Purpose

This work instruction documents the current Lockbox assembly process from printed parts through final mechanical assembly.

Use these instructions with the active PCB and CAD release for the build.

Required parts and consumables

1. Gather the required parts before starting assembly.

   

   Required Lockbox assembly parts.

2. Confirm the assembly set includes:

   • top-housing
   • bottom-housing
   • pcb-backing
   • locking-latch
   • enter-button
   • back-button
   • encoder-wheel
   • encoder
   • motor
   • screen
   • battery
   • 7x torx-screw
   • 4x 4mm-magnet
   • 4x rubber-foot
   • VHB-double-sided-tape
   • hot-glue
   • SA-glue

3. If all required parts are present, continue onward.

Tools

• Electric screwdriver or hand driver with T7 Torx bit
• flat-jaw-pliers
• tweezers
• paperclip
• isopropyl-alcohol
• microfibre-cloth

Prepare plastic components

1. Work on a soft cloth. The front face scratches easily.

2. Check each printed part in good lighting before assembly. Look for curled corners, squished layers, large plastic blobs, blocked magnet inserts, and blocked screw holes.

3. Use a smooth PEI print bed for front-facing cosmetic parts and a textured PEI print bed for internal parts.

4. Inspect each printed part before installing electronics.

5. Confirm the plastic components are clean, correctly printed, and free of obstructions before continuing.

Part reference photos

Use these photos while inspecting printed parts.

top-housing

Top housing.

Top housing side view.

bottom-housing

Bottom housing.

Bottom housing side view.

motor-clamp

Motor clamp.

Motor clamp side view.

pcb-cover

PCB cover.

PCB cover side view.

encoder-wheel

Encoder wheel.

Encoder wheel side view.

locking-latch

Locking latch.

Locking latch side view.

enter-button

Enter button.

Enter button side view.

back-button

Back button.

Back button side view.

Install magnets

1. Install four magnets: one in the locking-latch, one in the top-housing, and two in the bottom-housing.

2. Use a paperclip to lightly coat the inside of each magnet insert with SA-glue.

   

   Apply a light coat of glue inside the magnet insert.

3. Check magnet polarity before pressing each magnet into place:

   • locking-latch: north pole up
   • top-housing front magnet: south side up
   • bottom-housing front magnet: north side up
   • bottom-housing back magnet: south side up

Top housing front magnet polarity.

Bottom housing front magnet polarity.

Bottom housing back magnet polarity.

4. Use flat-jaw-pliers to press magnets into their inserts. Place a folded microfibre-cloth between the pliers and the Lockbox body to protect the printed surface.

Protect the housing while pressing magnets.

Press the lock arm magnet into place.

5. Confirm each magnet is seated flush or deep enough for its insert.

Top housing magnet installed.

Bottom housing back magnet installed.

Locking latch magnet installed.

6. Confirm the magnets are fully seated and glued before continuing.

Install screen and battery

1. Remove the protective film from the screen.

2. Align the screen with the top and right ledges of the top-housing.

3. Hold the screen in place and set it with hot-glue at the corners and remaining edges.

4. Wipe the rear of the screen and the side of the battery with writing using isopropyl-alcohol.

5. Apply a 3/4 inch square piece of VHB-double-sided-tape to the writing side of the battery.

   

   VHB tape applied to the battery.

6. Place the battery face down on the back of the screen with the cables exiting toward the lower right. Set with hot-glue as needed.

Screen and battery installed in the top housing.

Screen, battery, and motor layout reference.

7. Confirm the screen and battery are secure and that wires remain accessible.

Install encoder

1. Test-fit the encoder-wheel before soldering or gluing.

2. Apply SA-glue to the flat face of the encoder shaft.

3. Line up the flat of the encoder shaft with the flat face inside the encoder-wheel, then install the wheel.

4. Solder the encoder onto the PCB. Make sure the encoder is fully seated so the wheel stays straight.

Encoder installed on PCB.

Encoder wheel installed.

5. Confirm the encoder wheel rotates freely before continuing.

Install motor

1. Check motor polarity before installing the motor assembly.

2. If soldering the motor lead during this build, cut the motor connector lead length to 7 cm before final routing.

3. Place the locking-latch on the motor. Do not glue the latch to the motor.

   

   Locking latch placed on the motor.

4. Slide the latch onto the motor assembly about halfway, then place the motor in the top-housing.

Latch installed about halfway on motor.

Motor placed in housing.

5. Place the motor-clamp over the motor and secure it with 2x torx-screw.

   

   Motor clamp installed.

6. Confirm the motor is seated and the latch can move without obstruction.

Install buttons and PCB

1. Place the enter-button and back-button into the button holes.

   

   Buttons placed in housing.

2. Place the back-button on the left and the lock/enter button on the right.

3. If the buttons are not already populated, solder the buttons onto the bottom of the PCB, the side with no other components.

4. Place the PCB onto the buttons so the encoder-wheel passes through the front hole.

   

   PCB placement over buttons.

5. Do not cover the screen-ribbon-wire, battery-wire, or motor-wire.

   

   PCB seated in housing.

6. Confirm the buttons actuate correctly and the encoder wheel is centered in the opening.

Connect cables

1. Open the screen ribbon connector latch.

2. Insert the screen-ribbon-wire, then close the latch. The lower white bar should not be visible after the latch is closed.

3. Plug the battery-wire and motor-wire into the PCB.

4. Route the motor wires left and over the PCB.

5. Keep the battery cable away from the mounting hole below it so the cable does not get pinched by the cover.

Screen, battery, and motor cables connected.

PCB cable routing reference.

6. Confirm each cable is fully seated before continuing.

Install PCB cover

1. Place the pcb-cover over the PCB.

   

   PCB cover placement.

2. Secure the cover with 5x torx-screw.

   

   PCB cover installed.

3. Confirm no wires are pinched under the cover.

Install rubber feet

1. Glue 4x rubber-foot onto the backplate.

Rubber foot closeup.

Rubber feet installed on backplate.

2. Confirm all four feet are present and secure.

Final assembly

1. Slide the backplate onto the main housing.

Backplate sliding onto housing.

Final Lockbox assembly.

2. Assembly is complete. Continue to functional testing.

QC checklist

• Confirm all required parts were present before assembly.
• Confirm printed parts are free of curled corners, squished layers, large blobs, blocked magnet inserts, and blocked screw holes.
• Confirm magnets are installed in the top-housing, bottom-housing, and locking-latch.
• Confirm all 4 magnets are installed with the documented polarity.
• Confirm the screen and battery are secured with hot-glue.
• Confirm the screen-ribbon-wire is latched and the lower white bar is not visible.
• Confirm the encoder is soldered and the encoder-wheel rotates freely.
• Confirm the locking-latch is placed on the motor without glue.
• Confirm motor polarity and, if built by hand, the 7 cm motor connector lead length.
• Confirm the motor-clamp is secured with 2x torx-screw.
• Confirm the motor clamp is straight.
• Confirm the PCB is seated without covering the screen-ribbon-wire, battery-wire, or motor-wire.
• Confirm the screen-ribbon-wire, battery-wire, and motor-wire are connected.
• Confirm the buttons click cleanly.
• Confirm the encoder wheel is aligned in the front cutout and spins freely.
• Confirm the pcb-cover is secured with 5x torx-screw.
• Confirm 4x rubber-foot are installed on the backplate.
• Confirm the backplate slides onto the main housing.