I wanted to plug my Cardputer into my Android phone, just for the bigger screen. Then it hit me: why the Cardputer at all? Plug a bare ESP32-S3 into the phone and run the firmware straight from the ESP, with the phone as its screen and keyboard. Anyone with an ESP32-S3 (not just any ESP) and an Android phone with OTG potentially has a Cardputer. That's Droidputer.
porkchop firmware running on esp32 powered by android device
- The shim: the app's source is never changed. Only the graphics and keyboard libraries under it are patched to copy every screen write to the phone and to merge the phone's key presses into the app's keyboard. M5GFX/M5Cardputer apps work, and TFT_eSPI apps (ESP32Marauder and its forks) now run through a virtual display driver plus an emulation of the Cardputer's keyboard matrix.
- The link: framed messages over USB-CDC, with run-length compression. A full screen that is 64, 800 B raw travels in about 10 KB.
- Build on demand: phone → a small proxy → GitHub Actions → firmware parts back to the phone. A typical build takes 2–4 min; big apps take longer. A repeat request comes back from the proxy's cache in seconds.
What you need- An ESP32-S3 board plugged in through its native USB port (the one labeled USB, not the UART/COM one). Classic ESP32 boards and UART-bridge ports can't carry the link.
- An Android 8+ phone with USB-OTG, and a data-capable OTG cable.
- Droidputter from Google Play.
What runs today (bare ESP32-S3 devkit, flashed from the phone, October 2026)
stellar-map, the M5Cardputer example, miniacid, ISS tracker, M5PORKCHOP, ESP32Marauder, Ultimate-Remote, BT Keyboard/Mouse Emulator, Tiny-Journal, System Monitor, audiospectrum and WebRadio all boot and mirror on the phone. Their public verdicts are in the repo.
Honest limits- Only open-source apps rebuilt against the shim mirror. Prebuilt binaries from the catalog flash but don't mirror.
- Some apps don't run yet: Pigtail reboots after its first frames, and Bruce needs a newer arduino-esp32 core.
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