An Entire Retro Gaming System Inside an NES Gamepad

If you look inside a retro gaming console, there is a pretty good chance you’re going to find a lot of empty space. This is because even really inexpensive modern hardware is far more powerful than what an emulator for a 1980s console needs. A common microcontroller with a few hundred kilobytes of RAM will generally do the job.

YouTuber Logic Gate Labs was recently poking around inside a retro console and found that the NES-style controller it used was also mostly free space. That gave him an idea: Why not build an entire handheld gaming system into the controller? So, that’s exactly what Logic Gate Labs did — and it might be easier to do than you’d expect.

To get started, the electronics were removed from the controller, leaving only the plastic shell, buttons, and D-pad. That left just enough room to fit a Wemos ESP32 S2 Mini development board, a 1.54-inch 240 × 240 TFT display, a MicroSD card module, a 500 mAh lithium-polymer battery, a TP4056 charging board, a small speaker, and a slide power switch.

There were many different ways Logic Gate Labs could have gone with this build. An ESP32-S3 would have offered dual-core performance and enough PSRAM to keep entire game ROMs in memory, reducing loading delays and stuttering. However, the larger board would not fit inside the controller housing. Smaller ESP32 variants without PSRAM were also ruled out because they lacked the memory needed for smooth emulation.

To get everything to fit, internal plastic supports were trimmed away to make room for the display, and new openings were drilled for the screen, USB charging port, MicroSD card slot, power switch, and speaker. To avoid having to route multiple ground wires to the microcontroller, a thick bare copper wire was installed as a central ground distribution rail, and thinner signal wires replaced bulkier wiring to make closing the enclosure possible.

On the software side, the system runs the Retro-Go emulator framework, compiled using ESP-IDF and CMake since the ESP32-S2 is not a standard Retro-Go target. The finished handheld is capable of emulating a variety of classic 8-bit systems for surprisingly little money. Logic Gate Labs estimates the complete build costs around $17 using commonly available parts, or roughly half that if components are sourced directly from overseas marketplaces.

As a bonus, the creator even managed to get Doom running by adding the PrBoom-Go engine and loading a Freedoom WAD from the MicroSD card. Performance is limited to roughly 5 to 15 frames per second, but considering the entire gaming system lives inside what used to be an empty controller shell, that’s still a pretty impressive result.