USB-NES lite DIY Kit

3D Print & Build Your Own USB-Based NES Game Player: A Step-by-Step Guide For Hackers, Electronic Hobbyists and NES Enthusiasts

Brad Taylor
06-17-2021
05-12-2022 (kit now includes power system electrolytic capacitor)

What is USB-NES?

• An easy way to play and backup Nintendo NES cartridges on modern computers
• Turns the NES cart into a standard USB flash drive
• Manage battery-backed save game files
• Works on PC, Mac, Linux and on modern smartphones
• Firmware is USB upgradable for future-proofing
• More info here.

Step 1: What you’ll need

• USB-NES Lite parts kit _{(sold out)}
• USB-NES 3D print model
• Filament 3D printer
• Fine-tipped soldering iron + station + solder
• Solder wick (optional; for removing solder bridges and excess solder)
• “3rd Hand” PCB holder
• Magnifying glass (optional; for inspecting solder joints)
• Flat-tipped or electronics’ tweezers
• Lineman’s pliers / needle-nose or similar type
• #1 Phillips screwdriver
• Utility knife
• Intermittent soldering skills
• Patience and persistence (estimated 1 hour assembly time)

Step 2: Open and Examine the USB-NES assembly kit

• 1x Protective jewel case
• 1x STM32 barebones system “blue pill” board (preprogrammed with current USB-NES firmware)
• 1x 40-pin single-inline header
• 1x 4-pin single-inline header
• 1x 6-pin dual-inline header
• 1x thin jumper wire
• 1x Printed circuit board “USB-NES-01”
• 1x 72-pin NES cart connector
• 1x surface-mount 10k-ohm resistor
• 1x surface-mount P-channel power mosfet
• 1x surface-mount level shifter
• 1x 3ft. Micro-USB cord
• 4x #4-40 x 1″ machine screws
• 2x #4-40 x 11/16″ machine screws
• 1x 560 uF electrolytic capacitor (after 05-01-2022)

Step 3: Prep the pin headers

• Break the 40-pin header into 2 equal sections of 20 pins.
• Use pliers to straighten the 4-pin header
• Use pliers again to slide the 4-pin header spacer down to be equal to that of the other 20 pin ones.
• Remove and discard the 2 yellow jumpers from the 6-pin header.

Step 4: Prep the blue pill board

• Remove and discard R4 from the board with the soldering iron by heating both sides of the surface mount resistor and pushing it away from the other components.
• Tin one end of the thin jumper wire that came with the kit.
• Use the thin jumper wire to bridge R4. Cut the excess wire off neatly with a knife.
• (optional) Apply some extra solder on the 4 mounting holes for the micro-USB header to improve structural integrity.

Step 5: Prep the USB-NES board with the surface mount parts

• Place a small amount of solder on a single pad within the part’s footprint.
• Use the tweezers to place the part on top the board oriented with the footprint; hold it steady.
• Heat the soldered pad with the soldering iron while pressing the part against the board until the lead from the part makes a good bond with the solder.
• Solder the rest of the leads of the part to the pads.
• Repeat this process for all 3 surface mount parts.
• Use a magnifying glass to inspect for good solder joints and identify any solder bridges on the surface mount parts (especially on the 5-lead level shifter chip).
• Use solder wick to clean up any bridges or excess solder.

Step 6: Stuff the pin headers into the USB-NES board

• Stuff the 2x 20-pin and 6-pin headers long-side-up into the topside through-holes of the blue pill footprint.
• Make sure the header spacers are flush with the surface of the board.
• Repeat all these same steps for the 4-pin header afterwards.
• Use pliers or other means when inserting tight headers.

Step 7: Solder the blue pill to the pin headers on the USB-NES board.

• Place the blue pill ontop the headers with the USB port facing upwards, and press it flat against the header spacers.
• Solder all the pin header joints to the blue pill.
• Flip the board around and apply solder in the 4 corners of the blue pill footprint. Keep the blue pill as flat as possible against the mainboard.
• Solder the rest of the pins to the mainboard.

Step 8: Solder the 72-pin cart connector to the USB-NES board

• Carefully line up the pins on the cart connector to the through-hole footprint on the top of the board and push it in flush with the board.
• Flip the board over and solder the pins on all 4 corners of the connector to the board while pinching the connector flush against the board from the other side.
• Solder the rest of the connector pins to the board.

Step 9: Solder the electrolytic capacitor onto USB-NES

• Follow steps 4 – 9 of the Power System Upgrade guide to install the 560 uF electrolytic capacitor.

Step 10: Test the USB-NES

• Plug the micro USB cable into the blue pill and the other end into a computer.
• A red LED should light up on the blue pill; this indicates the USB is supplying 5 volts to the blue pill.
• A green LED should momentarily light up; this indicates the firmware’s attempt to detect an NES cartridge.
• A removable storage media device should show up on your computer.
• The removable storage device should have readable files like README.TXT, VERSION.TXT and REPORT.TXT in the root directory.
• When the device is plugged in with an NES cartridge attached, a ROM.NES file should be present.
• Open the ROM.NES file on your computer’s NES emulator to test it.
• Do not remove or insert NES carts when the green LED is on.
• Changing NES game cart media usually involves unplugging the USB connection from the computer first.
• Sometimes the reset button can be used to invoke an NES cart media reset on the host computer.

Step 11: Download and print the USB-NES Lite 3D models

• Download the 3D model print package
• There are 5 models in the package. An extra, alternate bottom model that has no branding is also provided to reduce print time by ~1 hour).
• Use your favourite slicer to organize the models as you see fit for your filament printer.
• Print all 5 models: top, middle, bottom, dust cover hinge, reset button.
• Use a 5% infill for all prints.
• Set top/bottom walls to 1.2 mm.
• For PLA, use 220°C to get the best results on fine details like lettering on the first print layer.
• Use a 52° – 55°C print bed temperature to minimize print warping and curling. A confined printing enclosure is recommended for best results.
• Do not print supports.

Step 12: Assemble the USB-NES case

• Use your knife to cut away any excess plastic around the hinges of the dust cover.
• Cut away any debris on the sides of the interlocking parts.
• Wipe any fine strings away on the PLA print with a clean cloth.
• Carefully pop the the dust cover door into the bottom piece by positioning the door hinges on top the back rockers and pressing in.
• Adjust the door hinge so its angle is flush with the bottom piece.
• Place the reset button through the hole of the top piece print from the bottom.
• Pop the fully-assembled USB-NES board into the middle piece print.
• Pop the bottom of the middle assembly into the bottom assembly. Watch the bottom posts of the middle assembly align with the hole cutaway for the back rockers on the bottom piece.
• Sandwich the top and bottom assemblies together.
• Use the 4 x 1″ screws to fasten the 3 layers together using the holes closest to the NES cart slot. Do not over-torque the screws.
• Use the 2 x 11/16″ screws to fasten the layers together using the holes closest to the front of the unit. Do not over-torque the screws. Do not over-thread these screws or they may pop out the top of the unit.
• And that’s it!