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Pokémon Tamagotchi using Digispark - Help needed

herrlichakafool

Hello element14 community,

 

i found an old Gameboy Color in my basement with Pokémon Red in it, and since i am looking for a project for quite a while now,

i am willing to sacrifice it for the sake of modding.

 

Since my knowledge of electronics is basic, i hoped that some of you could help me out.

But first let explain my idea:

 

There used to be an interactive stream on twitch.com which allowed all viewers to play Pokémon at the same time.

People where able to enter one of 7 commands in the chat (Up, Down, Left, Right, Start, A, B),

which where then interpreted as commands for an emulator running Pokémon.

 

Example:

TwitchPlaysPokemon - Twitch Plays Pokemon (Red) 12d20h37m ~ 14d14h50m - Twitch

 

These semi-random inputs led to hillarious moments, which i want to recreate (sort of) by using an old Gameboy Color and a Digispark.

 

The idea is that the Digispark (which is a tiny Arduino-like microcontroller) enters random key inputs into the Gameboy, so it plays the game for itself.

When i started this project, i soon ran into some problems that i can't solve myself:

 

1. The schematics:

 

I generally know how to do it, but when it comes to really doing it, i fail. My Digispark can deliver 5V on each pin, when i measured the voltage on each button

i got about 3.4V. The output of the Digispark can be regulated, but i am sure that i need some resistors in my project. Any ideas?

 

2. Not enough pins

 

Here is a 3D render of a Digispark.

digispark-mini-arduino-newdesign.jpeg

As you can see, it has 6 pins. But the project requires 7 output sources. This could probably be done by creating a matrix, but again my knowledge is not advanced enough. Can someone give me a hint?

 

I would be really thankful for any kind of response. I don't want to accidentally trash my Gameboy, that's why i created this post.

Parents

  • Dear: Theo

    I see what your problem is. Would it hurt to just use a different microcontroller or am I missing something. Microcontroller ATTINY would work fairly good for this.

    From: Noah

    Adafruit Trinket - Mini Microcontroller - 5V Logic

  • in reply to nschreiber0813

    Hey,

    thanks for the reply. What advantages would an ATTINY have? In general it would be great if the microcontroller would fit somewhere inside the housing of the Gameboy.

  • in reply to herrlichakafool

    Dear: Theo

    There are many advantages towards using atmega Atiny. First of all attiny is small and can probably fit in your gameboy. Second of all it has more pins so it will solve your problem. Third reason is that it can preform well enough to fill your needs. The only problem with it is that you are going to need to design a PCB to fit your needs but you already were going to do that since you choose the project you choose.

    From: Noah

  • in reply to nschreiber0813

    Does an Atiny really have more pins?

    And a Digispark does fit just beautifully inside the Gameboy housing.

    I have several of these laying around in my home, so i thought it would be reasonable to use them.

     

    Besides, do i really need to order a custom PCB? There would not be much circuitry added exept

    some resistors, at least that's what i think.

    20871c5ee39c5db6c6878b4ef3329e82.png

    331bf6d637315e130256e3f072c60695.png

  • in reply to herrlichakafool

    I'm the creator of the Digispark - to clear up a few things:

     

    The Digispark is an ATTINY development board it uses the Attiny85 microcontroller and allows it to be programmed over USB with the Arduino IDE

     

    The Trinket made by Adafruit - which is what Noah posted a photo of - is exactly the same hardware - Adafruit released this version after the Digispark's success. The Digispark has a much bigger user community behind it at digistump.com/board

     

    The Digispark you have pictured is a counterfiet clone - you can tell because it does not have our web address "digistump.com" on the back. Most of these don't work or fail quickly due to improper parts (mostly the zener diodes and protection diode). If you'd like to get the real thing go to digistump.com - we also support all users of real digisparks through our wiki at digistump.com/wiki and our forums at digistump.com/board

     

    You may be able to do something like this to get two outputs from one pin: Batsocks - Controlling Two LEDs per uC pin

     

    We also sell a expander kit that adds 8 more outputs to the Digispark

     

    To get your 5v outputs to 3.5v you could use a resistor divider (voltage divider), you could put a 3.5v zener diode from that pin to ground, or you could use a level shifter chip.

     

    Hope that helps direct you down the right path.

  • in reply to Former Member

    Thank you for your reply Erik!

    When i purchased my Digispark i did not know that it was a fake, sorry about that. Just got one from ebay since it was the easiest way do purchase one.

    Also thanks for your hint about using a resistor divider, i will read into it.

     

    It seems that the expander kit is the most straight foward  way of doing it, that's why i ordered an original Digispark + I/O expansion.

    Some workaround has to be made since the depth of the expansion ontop of the Digispark probably makes it too bulky to fit at the spot i intended it to be.

  • in reply to herrlichakafool

    Theo -

     

    Thanks for your support!

     

    You can wire the expander shield with wire so that you can place it anywhere - just connect Digispark -> Expander as follows:

    GND->GND

    5V->5V

    P0->P0

    P2->P2

     

    Those are all the connections needed for the expander.

     

    Thanks,

    Erik

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