This guide will show you how to assemble the daddelkischde boards and modify your case to fit everything. Follow the instructions step by step from top to bottom to avoid missing out on important steps or tips.
- Parts and tools
- Make space
- Enlarge display opening
- Drill holes for X and Y
- Drill holes for L and R
- Board for L and R
- Modify HDMI display
- Disconnect the panel from the board
- Remove touch screen
- Remove switch and sockets
- Cut the board
- Tips and tricks
- Optional: build your own HDMI cable
- Optional: dummy cartridge
- Optional: close the barrel plug hole
- Optional: micro USB cover
- Optional: change display logo
- Optional: display energy optimization
Important: Before working with the boards, ground yourself to prevent damage to the electronics caused by electrostatic discharge. Ideally, you use a grounding bracelet. But you can also briefly touch a heater or the metal housing of a computer before touching the boards. Nevertheless, you should avoid touching the components directly on the boards.
Important notes about the battery
The daddelkischde should always be operated with a battery, not only by external power supply. The charging circuit only works properly when a battery is connected.
Even if the daddelkischde is switched off by a switch, the charging circuit is still powered by the battery. This serves to charge the daddelkischde in the off state. The consumption is only a few milliamps. Nevertheless, the battery should be disconnected if the daddelkischde is not used for a long time.
For charging, a power supply unit with at least 1 A output power should be used.
Do not connect high-consumption devices directly to the external USB port. So no external hard drives, wireless sticks, etc. Use an actively powered USB hub, so as not to stress the battery too much.
The battery should have enough space in the battery compartment. LiPos can expand and in the worst case explode if they do not have the space! Therefore, there should always be a few millimeters of air around the battery.
Parts and tools
You need these parts to build a complete Game Boy Zero with the daddelkischde:
- Daddelkischde kit including pin header, volume control and headphone jack
- Raspberry Pi Zero (W)
- Game Boy case (please do not disassemble an original Game Boy, that would be too bad)
- 3,5" HDMI display (from KeDei for example)
- LiPo battery (3.7 V), fits the battery compartment, with JST plug
- Protective glass for the display
- Mini HDMI type C to HDMI type A cable
- On/off switch (slide switch)
- Speaker (8 ohms, 1 watt, 28 mm)
- Additional buttons and pads for X, Y, L and R
- Stranded wire (AWG 26 for example)
- LEDs (3 mm, red, green, yellow, blue)
- Printed display holder
- Printed shoulder button holder
- 4x M2 flat head screw, approx. 6 mm long (for screwing on the shoulder key board)
- 5x M2x8 pan head screw (to screw the main board)
- Adhesive (two-component epoxy resin)
- Electrical tape
- Optional: Empty cartridge (as dummy)
The following tools are needed for assembly:
- Flat-nosed pliers
- Side cutter
- Soldering iron with fine tip
- Step drills
- Multimeter for checking the wiring
First, the three boards must be separated. Use a flat-nose pliers and break the boards apart at the predetermined breaking points. Make sure that the force acts on the predetermined breaking points and not on the circuit boards themselves!
Before the boards are soldered together, the headphone jack and the volume control should be assembled.
Insert the volume control into the holes provided and solder it from the bottom. Make sure that it rests as flat as possible on the board, otherwise it will later grind on the case.
Place the board on an elevation (on the assembly helper 1 for example) and insert the headphone jack. Solder it to the solder joints. Some headphone plugs are thicker than others, so more power is needed to insert and remove them. So that the headphone jack does not break off, you should also glue it with enough adhesive to the board.
Important: Without the headphone jack no sound is output at the solder pads for the speaker!
Before the two boards of the daddelkischde and the Raspberry Pi are soldered to the pin headers, the pin headers must be shortened. If the pin headers are shortened when already soldered, there is a risk that the boards will be damaged by the shear forces. Use a side cutter to cut the long pins to 3 mm (same length as on the short side). Hold the pin you cut. Otherwise it will fly away and in the worst case into your eye!
We recommend you to use our assembly helpers from the downloads. This makes it easier to assemble the boards with the Raspberry Pi Zero.
Use the assembly helper 1 and put the main board, a pin header, the helper board, a pin header and finally the Raspberry Pi over each other. Then solder the sides of the pin headers facing up.
Then use the assembly helper 2 to solder the backs in the same way.
In the original Game Boy case, there are a number of bars, pins and supports that need to be removed for the daddelkischde. Most can be broken out with flat-nose pliers or can be removed with a side cutter. The remains can be easily removed with a file.
Remove the parts marked red in the following pictures. If you are using the HDMI display, also remove the green area to make room for the HDMI cable. Depending on how accurately the case is made, the blue marked point must be deepened so that the large capacitor does not rest. This works well with a Dremel and matching sanding attachment.
At the openings for the micro USB port and volume control are bars, which should also be removed:
Depending on manufacturing variations, it is also necessary to slightly enlarge the opening for the battery socket. This is easy to do with a small file.
Newer versions of the KeDei display are a bit too wide for the case. Therefore, the side walls of the front case have to be sanded down a bit on the inside, so that the display fits in perfectly. The areas are marked red in the following picture.
Enlarge display opening
Depending on which display is used, the opening for the display must be increased. This can be done well with a Dremel. At the same time you should leave enough edge to avoid cutting too far. After the rough preliminary work with the Dremel the rest can be worked on with a file, so that a straight edge results. It does not matter if the edge does not look perfect. The screen protector will hide it later.
Alternatively, you can use a utility knife and ruler to dig furrows into the plastic, and then simply break out the edges. The sharp edges are then smoothed with a file.
Drill holes for X and Y
The X and Y buttons require additional holes in the front of the chassis. The display holder and the X and Y holder provide breakout drill guides so you can drill the holes in the right place. Place the holder (do not glue it!) In place and drill a small hole with the drill guide. Use a drill with little play in the drill guide to really drill in the middle.
Now you can remove the holder again. Use a step drill and drill the holes to 11 mm. With a countersink you can deburr the holes from outside and inside. Then the buttons will not hang and it looks nice too. The drill guides can then be broken out. The leftovers should be filed so the buttons won't grind later.
Drill holes for L and R
Drilling the holes for the L and R (shoulder) buttons works the same as for X and Y. Place the shoulder button holder in place and drill through the drill guides with a suitable drill bit. Remove the holder and use a step drill to drill the holes to 11 mm. Again, the holes should be deburred with a countersink from the inside and outside.
Board for L and R
When the holes for the L and R keys are drilled and the drill guides are removed, the shoulder button holder can be glued. The pad needs to be cut to fit. This works well with a nail scissors. After the glue has dried, the buttons and pads can be inserted and the board screwed down with four M2 screws. It may be necessary to shorten the screws beforehand. Make sure that the screw holes in the shoulder key holder are not too narrow. If there is not enough space, the holder could break when screwed in. It is best to prepare the holes with a tap for M2 or to enlarge them with a 1.8 bit.
Modify HDMI display
If you're using KeDei's HDMI display, it needs to be modified to fit the case.
Attention! Treat the display very carefully! The ribbon cable can be easily torn or cut. Do not exert any force on the panel or pull it, because otherwise pixel errors could occur or even break the display.
Disconnect the panel from the board
The first step is to disconnect the panel from the board. It is attached with two thick adhesive strips. First, carefully open the jack for the ribbon cable by folding the tab upwards. Then you can take out the cable, if it does not fall out by itself.
Then use a scalpel or another sharp knife to cut the adhesive strips in the middle. Be especially careful! You should not slip and damage something. Pay special attention to the ribbon cable!
Alternatively, you can use a hair dryer to heat the adhesive strips. Then the display can simply be removed from the board. Make sure that the display does not get too hot, otherwise it may be damaged!
The narrow cable for the touch screen can be cut through safely, the touch screen will be removed later anyway.
After the panel has been removed from the board, you can remove the remnants of the glue sticks. They are no longer needed because they make the display too thick.
Remove touch screen
With a sharp knife you can pry off the touch screen. This is the acrylic glass including the foil with black border and flex cable. First, carefully remove all sides before completely peeling it off. All that remains is the naked display, which is best covered directly with the protective foil and placed in a safe place to the side.
Some variants of the display have retaining lugs on the white plastic frame. They will be in the way later and have to be removed. This works well with a side cutter and a file.
Remove switch and sockets
The switch and the socket strips are in the way and must be removed. For the sockets you can use a side cutter and unsolder the remaining legs.
The switch can also be easily soldered out, with two soldering irons or additional solder, which connects all five pins and transfers the heat. When the switch is removed, the two pins facing the HDMI jack must be connected. Otherwise, the backlight is off. In the photo, the soldering bridge is clearly visible.
Cut the board
The display board is too wide for the case. Therefore it has to be shortened. The printed part contains no circuit paths and can therefore be sawn safely with a Dremel. As you can see in the picture, a small amount of the print should remain visible to maintain a safe distance to the circuits.
The back side of the board (without components) needs to be insulated so that no short circuits occur later. Therefore, glue over the solder joints with insulating tape.
Finished! Now you should test the display to check that it has not been damaged. Because after bonding it is not so easy to get it out of the case.
If the display is later installed, it is recommended to use two Tesa Powerstrips to glue the panel to the display board.
Insert the display into the display holder and use two Tesa Powerstrips to stick the board to the panel. If you want to use the angled HDMI plug, then put it on the display now. Then use two-component glue to glue the display in the case. From now on, there is no turning back, the display cannot be removed after drying the adhesive! Therefore, make sure that it is sitting correctly and is lying straight.
The following graphic shows how to connect the other components such as speakers, USB, LEDs, audio input and shoulder buttons.
Power supply for display
For the power supply of the display, three pads are available in the upper left corner: GND, 3.3 V and 5 V. Depending on which display is used with which modifications (energy optimization with KeDei display for example), not all pads are needed. At 3.3 V, a maximum of approx. 500 mA may be drawn, 450 mA at 5 V.
If you use the KeDei display without the energy optimization, then you only need two wires for GND and 5 V as shown in the following graphic:
The integrated 2-port USB hub is connected via two pads (D+ and D-) with wires directly to the Raspberry Pi. The overview diagram shows exactly where the corresponding pads are located on the Raspberry Pi Zero. The USB socket on the Raspberry Pi is thus occupied and cannot be used elsewhere.
For another internal USB device, the four pads for 5 V, D+, D- and GND are ready on the underside of the board. When using the HDMI display, these are not needed. Here, for example, a USB sound card can be connected.
When using the HDMI display, the sound is transmitted digitally via HDMI to the display. There it can be tapped at the jack socket. Here two wires are soldered, which are soldered to the "PhoneJack L / R" marked pads. From there, the sound first goes through the volume control and then goes to the headphone jack. If no headphones are plugged in, it is mixed to a mono signal and amplified. Finally, the sound is output to the pads for the speaker. Here you can connect a speaker with 8 ohms and 1 watt. To fit in the Game Boy case, it should have a diameter of 28 mm.
Attach a mechanical sliding switch to the two pads to turn the board on and off.
Important: Without this switch the Raspberry Pi will not be powered!
If you use a sliding switch with the dimensions 16 x 7 mm, you can use our switch holder, which holds the switch firmly in the case.
Solder one of the two wires to one of the central contacts, the other wire to a contact facing the outer side of the case.
Optionally four LEDs can be connected:
- LED device on: Lights up when the on/off switch is set to "on" and the board is receiving power
- LED battery empty: Lights when the battery voltage is 3.2 V or less
- LED batter charging: Lights when the battery is being charged via the micro USB socket
- LED battery full: Lights when the battery is fully charged and a power adapter is connected to the micro USB socket
The LEDs can be placed anywhere. Pay attention to the correct polarity when connecting the LEDs. Some LEDs are connected to the corresponding pin with their anode (+, shorter leg), others to the cathode (-, longer leg) (see wiring diagram). The resistors for the LEDs are already present on the board.
L and R keys
Connect the board for the L and R buttons with three wires to the corresponding solder joints on the outer edge of the board.
Tips and tricks
Tip: With UV glue, you can additionally fix the solder joints after soldering.
Improve the pressure point of the buttons
To improve the pressure point of the buttons, you can use M3 washers (max 6.7 mm outside diameter).
If the D-pad does not work reliably, you can fill the cavities with hot glue.
Optional: build your own HDMI cable
It's not easy to get a suitable HDMI cable. Therefore, here we show you how you can build one yourself.
- 120 cm very thin wire (diameter 0.1 - 0.3 mm), AWG 30 7/38 for example
- HDMI connector type A (male) angled to wide side or HDMI connector type A female
- Mini HDMI connector type C male
- Two-component epoxy resin
When using the wire, it is important that it is thin enough to be able to solder several strands together next to each other. Teflon-coated (PTFE) strands have proven to be useful because the jacket does not melt during soldering.
To connect to the display, you can either take an angled type A connector (note the direction of the bend to the wide side!) or you use the adapter supplied with the display and a type A connector. In our example photos, we use the latter.
Not all 19 pins need to be connected. We can do without the shielding of the signals, we do not need the signals reserved for Ethernet, nor do we need a 5 V supply voltage and no hot-plug detection. Thus, only 11 signals are needed.
First, the wire is cut to 11 cm long pieces, stripped on one side (about 2 mm) and then soldered to a connector using the table below. The easiest way is to start with the type C connector.
Subsequently, the line pairs (Clock, Data0, Data1, Data2) are twisted to achieve a better shielding. The strand is bent into shape as it will eventually be in the installed state. Then the strands are cut to the same length, stripped and soldered using the table to the second connector. If the function test was successful (also test the sound!), The solder joints can be glued with two-component adhesive. Thus, the solder joints are protected against short circuits and the whole cable is more stable.The graphics show the view of the plug. The solder pads are on the other side, so from the point of view of the solder pads the pins are mirrored. In the type C connector, the solder pads are usually arranged on both sides. The flat, longer plug side contains the odd pins (1, 3, 5 ... 19), the angled side the even pins (2, 4, 6 ... 18).
|Signal name||Pin number type A||Pin number type C|
Optional: dummy cartridge
To close the slot for the cartridge on the back, you can install a dummy cartridge. A complete cartridge does not have enough space, the HDMI cable and the shoulder buttons are in the way. Therefore, the cartridge must be cut. Use an empty cartridge, which you edit with a Dremel and file so that it is open on the inside. You can then decorate it with a sticker and glue it firmly to the case.
The cartridge offers itself to accommodate the LEDs there. In the downloads you will find a drilling template, with which you can easily drill parallel holes in the top of the cartridge.
Optional: close the barrel plug hole
The round hole in the case, which was used with the original Game Boy for a power supply, is superfluous. In the downloads you will find a small barrel plug, with which you can close the hole.
Optional: micro USB cover
The opening for the micro USB plug is larger than necessary. Again, there is a micro USB cover in the downloads to reduce the opening.
Optional: change display logo
The KeDei display shows the manufacturer's logo when switching on. With the help of an Arduino, a computer and a HDMI connector with three wires, the logo can be replaced by one of your choice. Alternatively, it is also possible without extra hardware. The required programs and instructions are available at GitHub.
Optional: display energy optimization
Important: This step is optional. It requires skill and is unsuitable for beginners as the display can be easily damaged. Please perform only if you are absolutely sure and can handle the soldering iron well! You can find a graphic for wiring the display without energy optimization under Power supply for display.
The display is normally supplied with 5 V. Internally, it also requires 3.3 V and 1.8 V, which it generates from three inefficient linear regulators. This unnecessarily converts electricity into heat. The Raspberry Pi provides 3.3 V and 1.8 V from much more efficient regulators and can thus also provide the display. All you have to do is remove the linear regulators on the display and, as shown in the photo, connect the Raspberry Pi and daddelkischde with wires to the display. The solder pad for 1.8 V on the Respberry Pi is located on the bottom, next to the solder pads for the USB socket.