I found these instructables : https://www.instructables.com/id/Game-Boy-Android-... and

https://www.instructables.com/id/Game-Boy-Game-Pad-... really awesome ! By the way, thanks to alpinedelta and tomatoskins.

In my childhood, I always have preferred the Sega Game Gear to the Game Boy. So, I wanted to make the same thing as tomatoskins but with this console. I share the same nostalgia about playing with the true game pad.

However, the bluetooth communication between a wiimote and recent smartphones doesn't work anymore. So, I had to find a different way to make it.

I hope you will like it ! :)

*Better video ASAP

Step 1: Parts Needed

Parts needed :

Game Gear (I bought a broken one) : 10 €
USB GamePad (ebay) : 2,55 €
USB OTG adaptater (ebay) : 1,86€
Smartphone (I used a Nexus 5 but with little adaptations any other smartphones should be ok) + Game Gear emulator app (I advise you Nostalgia GG Pro)
Extruded polystyrene foam (underlay for parquet)
Resistor (270 Ohm)
Game gear cartridge
Large black duct tape

Tools needed :

Hot glue gun
Soldering Iron + solder + wires
Desoldering pump
Screwdriver
Cutter
Ruler

Step 2: GamePad and USB OTG Adapter Disassembly

GamePad :

Remove all the screws holding the gamepad.

Desoldering the R1/R2 buttons and the L1/L2 buttons.

Cut the four USB wires.

Save the main board, we will use it in the 4th step.

USB OTG adapter :

Cut the plastic around the USB OTG adapter.

Melt down the hot glue around the wires wich relie the USB female and the Micro USB type B connectors.

Desoldering the wires of the Micro USB type B connector and solder longer wires.

Save the Micro USB type B connector, we will use it later in the 5th step.

Step 3: Game Gear Disassembly

Open your Game Gear. There are 5 screws holding your console together. One of these screws is a Sega security screw, you can remove it using an empty ballpoint pen. Heats up the head of the pen and push the warm plastic onto the security screw, push it hard enough so the plastic forms around the shape of the screw. Wait several minutes until the pen is cold, then use slowly the pen as a screwdriver.

Now remove all screws holding the main board. Remove the light, the metal shield, the wires, everything except the two little board in the top corners.

Use your dremel and cut the main board to remove the screen and its connectic.

On the bottom part of the console, cut off the plastic part on which we slide the cartridge.

Save the screws, the two part of the game gear, the right and the left side of the main board. We will use them in the next steps.

Step 4: Wiring the Game Gear and the Gamepad

Solder wires on the (1), (2) and (start) buttons on the right side of the Game Gear main board. Solder wires on the (up), (down), (right) and (left) buttons on the left side of the Game Gear main board. Make sure to label these wires so that you know what to solder where on the Gamepad.

Stick the Gamepad board on the two sides of the Game Gear main board with hot glue.

Solder on the Gamepad board the wires that you previously soldered on the Game Gear board : relie the (up) wire to the corresponding (up) Gamepad button. Do the same with the (down), (right) and (left) wires. Relie the (1), (2) and (start) wires where you want on the Gamepad buttons (we will be able to set the input buttons in the emulator app).

Step 5: Make a Nest for Your Smartphone

You don't want to scratch your screen phone ? Me neither ! So make a soft nest with extruded polystyrene foam to slide your smartphone in. It was the first time that I used extruded polystyrene foam, it's an interesting material. Easy to cut, to form and to stick.

So, cut some parts of extruded polystyrene foam and use your hot glue gun to assemble them as a puzzle to make a nest of the size of your smartphone.

Let a hole in the bottom center of the nest for the USB OTG adapter (Micro USB type B cf. step 2). Fill this hole with hot glue. Plug the OTG adapter to your phone and slide it inside the nest. The OTG adapter should be inside the hole. Wait several minutes until the hot glue is completely dry.

Next, remove your phone (now the OTG adapter should be correctly fixed inside the nest). Add a layer of extruded polystyrene foam on the top of the OTG adapter.

Step 6: Game Gear Reassembly

From now, the Game Gear is in two parts :

- the top which contains everything concerning the controls

- the bottom which contains the nest and the USB OTG adapter

You just have to solder the 4 wires of the USB OTG adapter to the 4 wires of the Gamepad board.

Then, you can reassemble these two parts using the 4 screws that you saved in the 3th step.

Step 7: Game Gear Emulator App

There is several Game Gear emulator apps on the Android Market.

But Nostalgia.GG is interesting for our project because it allows to customize the layout of game screen.

The layout of game screen is not saved using the Lite version of the app but the Por version is really not expensive (1,50€).

So, download the app (Lite or Pro, as you want), go to Preferences -> Game Screen Layout and place the game screen in such position that it can be seen when your phone is inside the console.

Then, go to Preferences -> Edit Profile and set controls.

Of course, you need to have some roms in your phone memory. The app detects them automatically.

At this point, your Game Smart Gear should be completely usable but some design improvements can be made in the next step.

Step 8: Improvements

How to improve the look of our console and increase the gaming nostalgia ?

Use large black duct tape to cover the extruded polystyrene foam.

Open a Game Gear cartridge (use the same method as in the first step to remove the special screw). Slide the top part of the cartridge between the extruded polystyrene foam and the back of the console.

Open the Game Gear and solder a 270Ohm resistor between the original Game Gear led and the +VDD (USB 5V) that you can find on the GamePad board. Solder the other pin of the led to the Gamepad ground. When your phone will be inside the console, the led will automatically turn on.

Thank you for reading (sorry for the errors, english is not my native language) and let me know if you have any questions.