Printward for Bambu Lab

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A standalone control panel and monitor for a Bambu Lab 3D printer that runs on an Android tablet — with a full web interface as well, so you can drive the printer from the tablet or from any browser on your LAN. A companion Printward Scale weigh scale (inspired by SpoolEase) adds real spool‑weight tracking. See Hardware.

When the tablet is idle it becomes a screensaver that draws the running print layer by layer, straight from the G‑code:

The interface is available in English, Dutch and German, switchable on the fly, and more languages can be added by dropping in a file — see lang/.

Installing? See INSTALL.md — the tablet app is a download‑and‑tap APK, and the scale flashes straight from your browser at the flasher page. No developer tools needed.

Features

• Live printer status & control over the printer's local MQTT feed (the broker inside the printer, reached on your network with the LAN access code — this works in the printer's normal cloud mode too, no "LAN Only" mode required): print progress, temperatures, and pause/resume/stop/light controls.
• Filament / AMS & spool‑weight tracking: remaining grams that count down as a print runs, plus the cost of each print. No extra hardware required — see the filament manager below.
• File browser over the printer's FTP service.
• Bambu Cloud integration for the one thing the local MQTT feed never exposes: how many grams a finished print actually used.
• LVGL touch UI (LVGL 9.3): printer screen, filament/AMS, file browser, settings.
• On‑screen setup for the printer connection (IP / serial / LAN access code).

On the Android‑tablet / web build, additionally:

• Manual motion ("Move"): jog X/Y/Z, home, extrude/retract, and — in LAN mode — temperature presets.
• Full web control on :8080 mirroring every tablet screen (dashboard, filament, files, move, scale, spools, settings), password‑protected and answering only on your own network.
• Filament manager (no scale required): a spool library (create/edit/copy/search/bulk‑edit). Enter a roll's weight and the remaining grams tick down live during a print (the sliced file's total × progress), with price / cost / remaining‑value and a "will this print run short?" warning. The optional Printward Scale lets you weigh instead of type — and re‑weigh for the exact figure — while the Bambu Cloud relay (below) can feed each print's real grams to keep it accurate without a scale.
• ntfy push notifications (print done/failed, filament short), print history & statistics, and kiosk crash‑restart.

Note — temperature & starting prints. On recent Bambu firmware (≥ 01.08), the printer rejects set‑temperature and start‑print commands from third‑party tools unless it is in LAN Only mode. Printward has a LAN mode switch (Settings ▸ Printer setup): turn it on when your printer is in LAN Only and the temperature controls and print‑start appear. In the normal cloud mode, leave it off and start prints from Bambu Studio / Handy — everything else here (monitoring, pause/stop, light, move/jog, AMS settings) works either way.

Hardware

• Android tablet — runs the LVGL UI (src/ui_*) as a standalone printer monitor/controller with a live local‑MQTT link to the printer, plus a full web UI on http://<tablet>:8080. Verified on a Samsung SM‑T280 (Android 5.1.1). See android/README.md.
• Printward Scale — an ESP32‑S3 + HX711 load‑cell scale that feeds real spool weights to the tablet for filament tracking, cost, and low/short‑filament warnings. It reuses the SpoolEase Scale hardware (design, wiring and 3D‑printed parts) with our own firmware; build it with SpoolEase's guide. See scale/.

Developed and tested on a Bambu Lab P1S. Printward talks to the printer over the local MQTT + FTP interface that Bambu Lab printers share, so other models (P1P, X1C, A1, …) should work too — they just haven't been tested here yet.

The exact same src/ui_* code also builds as a PC simulator (sim/) for development.

Build from source (developers)

Just want to use it? You don't need this — see INSTALL.md. This section is for building the app and firmware yourself.

• Android tablet — build the APK with the Android NDK + Gradle and push it to the tablet. Full step‑by‑step in android/README.md. The printer IP / serial / LAN access code go in /sdcard/printward.conf (see sim/android/printward.conf.example) or the on‑screen Printer setup.
• Printward Scale — open scale/ in VS Code with the PlatformIO extension and flash over USB‑C (environment printward_scale). First‑run WiFi setup and load‑cell calibration are described in scale/.

Security

The web interface controls a real printer, so it is not left open:

• Password. The tablet generates a random password on first run and shows it under Settings ▸ Web password — like a TV showing a pairing code, so there is no default password to forget to change and each device gets its own. Sign in as user printward.
• Local network only. The server refuses connections from outside your own network, so a forwarded port or UPnP can't put the printer on the internet.
• The printer's LAN access code stays on the tablet (in /sdcard/printward.conf) and is never included in a backup or exposed by the web interface.

It is plain HTTP, so the password crosses your own LAN unencrypted — enough to keep the printer off the internet and away from other devices on the Wi‑Fi, not a defence against someone actively sniffing your network.

Filament‑weight relay (tools/)

Bambu Cloud's login is behind Cloudflare bot‑protection, so a small Python helper runs on your PC instead: it logs in to Bambu Cloud, watches your print history, and reports the grams used by each finished print to the tablet over your LAN.

Setup:

1. pip install requests
2. Copy tools/config.example.json to tools/config.json and fill in your details (Bambu email, printer serial, the tablet's IP, port and web password - Settings > Web password on the tablet). config.json and relay_state.json are git‑ignored — they hold your credentials/token and must stay local.
3. Run it: python tools/bambu_weight_relay.py — leave it running while you print.

Notes:

• Verification code: about every 90 days a fresh login may need a 6‑digit code emailed to you; the relay asks for it in its terminal, so run it with a visible console for the first login.
• Windows convenience: encrypt_password.bat stores your password encrypted (bambu_password_enc, via Windows DPAPI tied to your account) instead of plaintext; start_relay_hidden.vbs runs the relay with no console window. These are optional and Windows‑only — on Linux/macOS just use a plaintext bambu_password in your (git‑ignored) config.json, or a custom_token.

How it started

Printward began as firmware for a small ESP32 handheld panel — somewhere to see what the printer was doing without opening Bambu Studio on a laptop. It worked, but the hardware ended up being the thing that limited it, and an old Android tablet turned out to do the same job better: a bigger screen, WiFi the OS already takes care of, and room to grow.

Grow it did — and the interesting part was not another status readout. It was the question that actually comes up in the workshop: how much filament is still on that spool, and what did this print cost me? Answering that honestly needs real weights, not a percentage guess, so a second device joined in: an ESP32‑S3 with a load cell — the Printward Scale. From there came the spool library, cost per print, the history and the statistics.

The ESP32 firmware has since been removed. What's left is the tablet app, its web interface, and the scale.

Credits

• Built on LVGL and SDL, plus the open‑source libraries listed in platformio.ini.
• The Printward Scale is inspired by SpoolEase by yanshay: it reuses the SpoolEase Scale hardware design, wiring and 3D‑printed parts, and runs our own firmware. Thanks for the great project and for being cool with this.

License

GNU AGPL-3.0 — see LICENSE. Copyright © 2026 sankeeye.

Free software: use it, study it, share it, improve it. But if you distribute it — or run a modified version as a network service — you must release your source under the same license. In short: it stays open, and no one can take it closed and sell it as their own product.

The AGPL covers the code, not the name "Printward" or its branding. Don't use the name or logo to suggest your fork, product, or service is official or endorsed by this project — fork freely, but give your version its own name.