Planet Arduino

Over the years we’ve seen plenty of homebrew handheld game systems that combine an AVR microcontroller, a few buttons, and an small OLED display. We’ve even seen some of them turned into commercial products, such as the Arduboy. They’re simple, cheap, and with the right software, a lot of fun. But being based on an MCU, most of them share the same limitation of only being able to hold a single game at any one time.

But not the Game Card, by [Dylan Turner]. This handheld was specifically designed so that games could be easily swapped out using physical cartridges. But rather than trying to get the system’s microcontroller to boot code from an external flash chip, the system relocates the MCU to the removable cartridge. That might seem a bit overkill, but given how cheap the ATTINY84A on each cartridge is, it’s not exactly going to break the bank.

With the microcontroller on the cartridge, the only hardware that stays behind on the Game Card is the SSD1306 128×64 OLED display, buttons, and the battery. That means the handheld is effectively non-functional unless a game is slotted in, but that could be said of most early cartridge-based game systems as well. On the other hand, it also opens up the possibility of producing cartridges with more powerful microcontrollers down the line.

Using a different microcontroller for each game is a neat hack, but it’s not the only solution to the problem. We previously saw a community effort to add expandable storage to the Arduboy in the form of a DIY cartridge, which ultimately led to the development of an official flash chip upgrade for the handheld.

The ArduBoy, as you might have guessed from the name, was designed as a love letter to the Nintendo Game Boy that many a hacker spent their formative years squinting at. While the open source handheld is far smaller than the classic DMG-01, it retains the same general form factor, monochromatic display, and even the iconic red LED to the left of the screen. But one thing it didn’t inherit from the original was the concept of removable game cartridges. That is, until now.

Over the last year, [Mr.Blinky] and a group of dedicated ArduBoy owners have been working on adding a removable cartridge to the diminutive handheld. On paper it seemed easy enough, just hang an external SPI flash chip off of the test pads that were already present on the ArduBoy PCB, but to turn that idea into a practical cartridge required an immense amount of work and discussion. The thread on the ArduBoy community forums covers everything from the ergonomics of the physical cartridge design to the development of a new bootloader that could handle loading multiple games.

The first problem the group had to address was how small the ArduBoy is: there’s simply no room in the back to add in a cartridge slot. So a large amount of time is spent proposing different ways of actually getting the theoretical cartridge attached to the system. There was some talk of entirely redesigning the case so it could take the cartridge internally (like the real Game Boy), but this eventually lost out for a less invasive approach that simply replaced the rear of the ArduBoy with a 3D printed plate that gave the modders enough room to add a male header along the top edge of the system.

As an added bonus, the cartridge connector doubles as an expansion port for the ArduBoy. While perfecting the design, various forum users have chimed in with different gadgets that make use of the new port, from WS2812B LEDs to additional input devices like joysticks or a full QWERTY keyboard. Even if you aren’t interested in expanding the storage space on your ArduBoy, being able to plug in new hardware modules certainly opens up some interesting possibilities.

In fact, the project so impressed ArduBoy creator [Kevin Bates] that he chimed in on the topic last month to announce he would start looking into integrating the community’s cartridge modification into the production hardware. If all goes well, pretty soon there might be an official upgrade path for those who want to expand what this tiny nostalgia machine is capable of.

[Thanks to Roo for the tip.]

The ArduBoy, as you might have guessed from the name, was designed as a love letter to the Nintendo Game Boy that many a hacker spent their formative years squinting at. While the open source handheld is far smaller than the classic DMG-01, it retains the same general form factor, monochromatic display, and even the iconic red LED to the left of the screen. But one thing it didn’t inherit from the original was the concept of removable game cartridges. That is, until now.

Over the last year, [Mr.Blinky] and a group of dedicated ArduBoy owners have been working on adding a removable cartridge to the diminutive handheld. On paper it seemed easy enough, just hang an external SPI flash chip off of the test pads that were already present on the ArduBoy PCB, but to turn that idea into a practical cartridge required an immense amount of work and discussion. The thread on the ArduBoy community forums covers everything from the ergonomics of the physical cartridge design to the development of a new bootloader that could handle loading multiple games.

The first problem the group had to address was how small the ArduBoy is: there’s simply no room in the back to add in a cartridge slot. So a large amount of time is spent proposing different ways of actually getting the theoretical cartridge attached to the system. There was some talk of entirely redesigning the case so it could take the cartridge internally (like the real Game Boy), but this eventually lost out for a less invasive approach that simply replaced the rear of the ArduBoy with a 3D printed plate that gave the modders enough room to add a male header along the top edge of the system.

As an added bonus, the cartridge connector doubles as an expansion port for the ArduBoy. While perfecting the design, various forum users have chimed in with different gadgets that make use of the new port, from WS2812B LEDs to additional input devices like joysticks or a full QWERTY keyboard. Even if you aren’t interested in expanding the storage space on your ArduBoy, being able to plug in new hardware modules certainly opens up some interesting possibilities.

In fact, the project so impressed ArduBoy creator [Kevin Bates] that he chimed in on the topic last month to announce he would start looking into integrating the community’s cartridge modification into the production hardware. If all goes well, pretty soon there might be an official upgrade path for those who want to expand what this tiny nostalgia machine is capable of.

[Thanks to Roo for the tip.]

While [Rob] was digging around in his garage one day, he ran across an old Commodore 64 cartridge. With no ROM to be found online, he started wondering what was stored in this ancient device. Taking a peek at the bits stored in this cartridge would require dumping the entire thing to a modern computer, and armed with an Arduino, he created a simple cart dumper, capable of reading standard 8k cartridges without issue.

The expansion port for the C64 has a lot of pins corresponding to the control logic inside these old computers, but the only ones [Rob] were really interested in were the eight data lines and the sixteen address lines. With a little bit of code, [Rob] got an Arduino Mega to step through all the address pins and read the corresponding data at that location in memory. This data is then sent over USB to a C app that dumps everything in HEX and text.

While the ROM for just about every C64 game can be found online, [Rob] was unlucky enough to find one that wasn’t. It doesn’t really matter, though, as we don’t know if [Rob] has the 1541 disk drive that makes this cart useful. Still, it’s a good reminder of how useful an Arduino can be when used as an electronic swiss army knife.