RKDR Solo Handheld - Assembly

Note: This procedure is constantly being improved. If you notice something that doesn't seem right, please email me and I'll make sure it's corrected and you get the right info. Now, lets get started! 

Step 1: Identify the Kits Part

  1. take the time to familiarize yourself with the parts in the kit.

  2. Download the 3D model / stl file for the main body here and an the shoulder button(s) here. these will need to be 3D printed using a material of choice. I prefer HIPS for its matte finish and workability but ABS and PLA will work fine as well.


Step 2: Necessary Tools

  1. Double-Sided foam mounting tape (for mounting the battery and LCD driver board)

  2. hot glue gun (to mount the switch and protect soldered momentary switch connections)

  3. soldering iron (to solder the electrical connections)

  4. 1/8" or 1/16" heat shrink tubing (to cover the switch and audio filter connections)

  5. toothpick (to clear remaining acrylic from face and rear panels)

Step 3: Inspect the Acrylic and rear faces

  1. Using a tooth pick, ensure all laser cut holes are clear of any acrylic material.

  2. If you find acrylic material lodged in a hole, use the toothpick to poke out the material.


Step 4: Inspect the Marque

  1. Using the same technique, ensure all laser cut holes are clear of any vinyl material.

Step 5: Prepare the Buttons

  1. Using cutters, remove connecting sprues from the buttons.
  2. Using sandpaper, remove any rough edges. 


Step 6: Apply the Marquee

  1. on a clean surface, place the D-Pad and four option buttons face up. These will serve as guide pins to align the placement of the marquee on the acrylic.
  2. gently remove the adhesive backing from the Marquee vinyl. 
  3. lay the vinyl sticky-side-up on the clean surface. positioning the vinyl and buttons to match up to respective holes.
  4. remove the protective coating from the matching side of the acrylic face.
  5. clean the acrylic surface with a soft cloth and air to ensure there is no lint or dust.
  6. carefully lower the acrylic face onto the marquee using the buttons as pilots to accurately position the face onto the marquee.
  7. press gently on the surface to adhere the marquee to the face.
  8. flip the acrylic face and remove buttons.
  9. using a credit card, rub the vinyl marquee firmly from the center out to remove any bubbles or wrinkles you may have.
  10. clean the center acrylic with a soft cloth
  11. set the face with marquee aside.


Step 7: Prepare the body

  1. position the body with the large + facing you.
  2. hold the body up to a light to observer the wiring holes.
  3. use a 1/16" drill bit by hand (or with a Dremel) to carefully open any holes that may be obstructed by plastic.
  4. Clearing any holes will ease the installation of the momentary switches in the next step.
  5. Install the power switch
    1. carefully insert and center the switch in the rear interface power switch enclosure.
    2. use a small dab of hot melt glue to secure the switch in place.


Step 8: Install the micro USB port

  1. test fit the small square USB port in the USB carriage located at the bottom near the round speaker mount.
  2. sand or file micro USB board edge to remove a small amount of the circuit board until it fits nicely into the carriage and the USB port is engaged in the lower external port.


Step 9: Installing the Raspberry PI Zero

  1. Carefully place the corner of the Raspberry PI Zero on the mounting pad towards the rear interface panel.
  2. install the mount screw, using one larger #4 screw
  3. gently rotate the PI pivoting on the screw to slide it under the power switch enclosure until the second hole and ports are seated to the rear interface panel.
  4. install the second #4 screw
  5. install the 3rd and 4th #4 mounting screws.


Step 10: Understanding the Momentary switches

  1. Note the Position and orientation of momentary switches
  2. Using a pair of flat needle-nose pliers, straighten the pins on each momentary switch. This will ease installment.
  3. Single Pole Momentary switches
    1. Each single pole momentary switch has four pins with two logical contacts. there are two pins for each contact when the button is pressed, the circuit is closed.
    2. Each momentary will require one contact to be grounded. and the other to be connected to a Raspberry PI Zero GPIO pin.


Step 11: Install Momentary switches

  1. install each momentary switch, in the correct orientation, in each of the 16 momentary switch sockets.
  2. ensure that each momentary switch is fully seated in its socket.
    1. if the momentary switch does not seat fully flush in the socket, remove the momentary switch and remove any debris from the cavity.
    2. repeat this for each momentary switch.
  3. rotate the body so that the momentary switches are face down, if any switches fall out, adjust the pins to provide tension to hold themselves in.
  4. using the black 30 AWG silicone wire and a soldering iron, solder one contact of all of the switches together in a the following manner. (use wire sparingly.) 
  5. using the white 30 AWG silicone wire and a soldering iron, solder the correct alternate contact on each of the switches to the respective GPIO pin on the Raspberry PI Zero. Be careful to ensure they are correctly wired based on the wiring diagram. (use wire sparingly.)
  6. using a hot melt gun, use a dab of glue on each pin to fix them in place and prevent any shortage of unused pins.


Step 12: Install the Powerboost 1000 module

  1. Using four of the small #2 screws, mount the Powerboost 1000 on the four dedicated mount holes located near the ABC/XYZ buttons
  2. using the black 30 AWG silicone wire, connect the EN and GND pins to the power switch.
  3. Connect the output + and - to the raspberry PI GPIO pins per the wiring diagram..
  4. Connect the USB and GND pins to the + and - pins on the micro USB.


Step 13: Create the Audio filter

  1. Solder the 33 n (yellow) and 150 ohm (brn-grn-brn) resistor in parallel / together
  2. Solder one pin of the 270 ohm (red-prp-brn) resistor to one end of the 150 ohm resistor
  3. Solder the end with three pins soldered together to the + side of the 10 uf electrolytic capacitor
  4. Use heat shrink tube or tape to insulate all of the soldered connections.


Step 14: Install the Speaker

  1. With the wires pointing left, carefully slide the speaker under the micro USB carriage into the speaker holder. The pressure from the carriage will hold the speaker in place. 

Step 15: Install the Mono Amplifier

  1. Using two of the small #2 screws, mount the amplifier on the two dedicated mount holes located near the ABC/XYZ buttons.
  2. Using the black 30 AWG silicone wire, connect the VIN and GND pins to the Powerboost 1000.
  3. Using the white 30 AWG silicone wire, connect the VIN and GND pins to the Powerboost 1000.
  4. Solder the speaker wires to the speaker connection on the mono amplifier.


Step 16: Prepare the LCD Display

  1. This step is delicate and will convert the 12v 3.5" display to operate on a 5v power supply.
  2. To modify the LCD screen we will remove an SOIC-8 pin chip from the video driver board. the board is responsible for converting the input power from 12-5v we will be removing the converter and injecting 5v power to the board directly at one of it's pads.
  3. Locate the chip to be removed. 
  4. Heat the four pins on one side of the chip to melt the solder.
  5. Using a toothpick or static safe tweezers, lift the side of the chip until the it is removed from contact. 
  6. Repeat the process on the second side to remove the chip from the board.
  7. Use a soldering iron and a solder sucker (or copper whick) to remove any excess solder from the pads.
  8. Using the black and white 30 AWG wire, solder a wire to the + and - respective circuit pads below.
  9. Take the driver board wiring harness connector and cut it to 4"
  10. Remove the insulation and all wires except the yellow and white, we will use this later. 
  11. Mount the Display
    1. Ease the video drive board through the gap between the speaker and the cross member.
    2. The Video driver board should be located on the same side as the powerboost and the mono amplifier.
    3. Place the LCD screen in the respective place holder in the front of the device.
    4. Remove the screen protector from the LCD screen


Step 17: Install the Face with buttons

  1. If your kit did not come pre-installed, firmly Insert the 4- 20 mm threaded standoffs into the 5 mm holes in the body until fully seated.
  2. Leave the remaining protective cover from the acrylic face to protect it during final assembly.
  3. Place buttons into the respective locations in the acrylic face
  4. Carefully invert the body while holding the LCD in place, facing down.
  5. Place the body aligned on the face.
  6. Carefully Flip the body and face over as a single unit. Ensure that all buttons are properly seated.
  7. Do not damage the video driver board which will be hanging.
  8. Using four M3 - 6 mm low profile cap head screws, attach the face to the body 
    1. Test the fit
      1. The D-Pad pivot:
        1. if you have a stiff d-pad when assembled:
          1. To suit your liking, it is to firm, remove the face and remove some of the material from the pivot, located in the center of the D-Pad switches.
          2. if the d-pad is still stiff: remove the d-pad and sand the bottom of the d-pad to remove some material. be careful not to remove the entire retaining flange on the d-pad.
        2. if you have a loose d-pad:
          1. remove the face and d-pad and apply a small dab of hot melt glue to the body to form a pivot to prevent the button from being too loose or pressing multiple switches at once.
      2. If any buttons are stiff or catch, double check and remove any excess material from the buttons.


Step 18: Mount the video Driver Board

  1. With the face installed the components installed in the front of the unit are stationary.
  2. Carefully flip over the unit.
  3. Using double-sided foam mounting tape attach the driver board to the cross member.
  4. Solder the + and - bypass wires to the Powerboost output + and -
  5. Connect the modified wiring harness to the video driver board connector.
  6. Solder the yellow wire to the TV pin on the PI Zero
  7. Solder the white wire to the 2nd pin on the "TV header" of the PI zero


Step 19: Connect the Audio Filter

  1. Solder GPIO 13 to the 270 ohm resistor in the audio filter we made earlier.
  2. Solder the 150 ohm resistor pins to the GND on the GPIO
  3. Solder the - side of the 10 uf Electrolytic capacitor to the A+ pin on the mono amplifier
  4. Connect the A- to the same GND as the 150 ohm resistor


Step 20: Mount the battery

  1. Using double sided foam mounting tape, mount the battery to the body in the right-side body compartment.
  2. Connect the battery to the Powerboost 1000 


Step 21: Mount the rear acrylic

  1. Place Shoulder buttons in their respective standoffs
  2. Remove the protective coating from the blank side of the acrylic (no logo)
  3. Place the acrylic panel on the body.
  4. Test the fit. if the shoulder buttons are too tight, remove any excess material and test fit again.
  5. Attach the acrylic to the body using four M3 - low profile cap head screws.


Step 22: Finish

  1. Remove the protective coating from the face and rear acrylic panels
  2. gently remove dust and test functionality.


Step 23: Install the software

  1. Download and install the Win32DiskImager from sourceforge.
  2. Download the correct card Image
    (based on the version of PI Zero board you have.)
    1. PI Zero v1.3
    2. PI Zero W
  3. Unzip the Disk Image file.
  4. Insert the blank RKDR sd card into your PC using a USB card reader.
  5. Using Win32DiskImager, select the RKDR Disk Image from the location that you extracted the file
  6. Select the drive letter of the blank SD card
  7. click on the write button.
  8. the image will be written to the SD card.
  9. Insert the SD card into the RKDR and reassemble the rear panel.
  10. Power on the device and Retropie will launch, pre-configured for the RKDR Solo Hardware.