Build your own Text Adventure in a Sega Handheld (Nerdkit)




I always wanted to create my own computer game.

Since I was playing around some time with my Nerdkit I thought it would be able to realise it with that.

So I started really from sratch with the code and the parts.

But pretty nice what turns finally out. I hope you like the result as much as I do.

You can download the whole project(PCBs and Code) in the download section.


Part 1 (Development Board V1 - General):


On a first prototype PCB I tried to do some tests.

I have ordered some 1x2, 1x4 keypads and a button to be able to choose between destinations, actions and skip text.

I used a 4x20 HD44780 Display with Backlight LED.

At this point everyhting worked great technically, but of course I wanted a much cooler case.



Part 2 (Development Board V1 - Buttons and PCBs):


Now I made the decision that the Sega Handheld has everything I need for my Text Adventure.

  • A Button to skip the text.
  • Two Buttons to choose between Action or Destination.
  • A cross for choosing between N, S, E and W.
  • An area for the display.
  • And place for batteries.


I was drawing some PCBs for the buttons to see if it works I expect.

It was really hard to find these eagle libraries for the button in the www.

Then I did my first tests and great, I didn't know it was that simple.



Part 3 (Development Board V1 - Display):


Because I didn't draw the my prototype PCB for Backlight PCBs I used my Breadboard correct this.

After that I had to cut some small wood pieces for the base of the display. I screwed the display in the available holes of the Sega frame.

It fits perfectly and display has the right position. Of course I have cut some plastic away the be able to have a full view at the display.

The original sega display was in fact a little bid smaller than the HD44780.

Now I was able to connect and light my new blue 20x4 HD44780 Display inside the Sega Handheld. Looks great, so far.



Part 4 (Development Board V2 - PCB Design):


Now it was time to design some PCBs which fit into the frame of the Sega Handheld.

Therefore I designed the following PCBs:

  • Mainboard (ATMega328)
  • Button Board Left
  • Button Board Right
  • Power Board


It was quite difficult to place all components on the Mainboard PCB because I drawed everyhting single sided.

After the measurement of all mounting points and holes the PCB were ready for creating.


To be more flexible I put a 10K poti for adjusting the contrast resistor.

For the backlight LED I chose a fixed 33K resistor.


The Power Board was designed to be able to be power by battery or wall mart. (But not both together - I was too lazy to implement some logic)



Part 5 (Development Board V2 - Power PCB):


I thought it would be the easiest way to desolder some parts from the original Power PCB to use them on mine.

Therefore I desoldered the battery metal contacts and the On/Off Switch.

Soldered them back in place on my Power PCB worked with some customizations, but looks good.



Part 6 (Development Board V2 - Mounting Points):


To make the small Button PCBs fit into the Sega case, I had create new mounting points.

Therefore I removed to original mounting points (red colour) and place them on a better position (green colour).

Some super glue did a great job. Now the Buttons PCBs are screwed tight to the case.


Additionally I had to remove another original mounting points (red colour) to create more room inside the Sega frame.

The HD44780 display is much thicker than the original Sega display, so I need to create some place. :-)

After the removal everyhting fits perfectly together.



Part 7 (Development Board V2 - Wiring):


So it was finally time to wire everything inside the Sega case.

A small challenge to place all the display cables in a good position to be able to close the Sega case without a problem.

But after some tries I found the correct position and I was able to close the Sega frame without a problem.



Part 8 (Development Board V2 - Final Assembled):


The first time I screwed everyhting together in the Sega case.

And yes, it worked like charm. No gaps, no problem, everything fits together like it should.



Part 9 (Development Board V2 - The Story):


I think this is a classic story. You are a brave knight who has to rescue the princess which has been kidnapped by a mighty dragon.

You can see on the screenshots how I tried to transfer the story into some pixel art.

I found some cool 8 Bit Art pictures on which I tried to display on the HD44780.



Part 10 (Development Board V2 - Navigating & Handling):


Room Description:

You are able to read the room description of every room. The description is devided into 3 screens.

So you have to switch through this 3 pages with a button. This is the Start Button on the Sega Handheld.


Choose Activity:

You are able to choose in every room between "Action" and "Navigation".

Therefore you can use the Buttons 1 & 2 on the Sega Handheld.

If you choose Action, you can pickup things or play some Action.

If you choose Navigation, you can choose the geographic direction (N, S, E, W) to move between the rooms.



In the upper right corner you will find a small inventory with space for 4 items.

Everytime you pickup an item the inventory shows it with a matching symbol.



To get a better understanding and making it easier to navigate in the medieval rooms I created a small map.

Looks pretty neat, I hope you like it.



To make better atmosphere I decided to implement some sound effect into the game.

For that I programmed some sounds of the classic game Zelda with my piezzo buzzer.

For example the Main Theme, The Dungeon, Pickup an Item and Locked Doors.