TigerScale

Purpose

TigerScale answers the eternal question: how much filament is left? Put a spool on the open-source ESP32 scale and the live weight flows straight into your inventory — no manual entry, no shaking the spool next to your ear.

A TigerScale V3 with a spool resting on it, its screen showing the weight, the filament it recognised and how much is left

The spool goes on, and the scale already knows what it is: the chip gives the brand, the material and the colour, the load cell gives the grams. Nothing typed, nothing guessed.

Install from your browser

TigerScale on tigersystem.io Print the case

Sources

The chip knows what the filament is; the scale knows how much is left. Together they make the inventory actually true: identity from TigerTag, live quantity from TigerScale.

TigerScale V3 — the current generation

Tiger-Scale-V3, MIT. This is the one to build.

It knows which spool is on it: dual PN532 NFC readers, one per side — a twin-tagged spool is identified whichever way you put it down. Read the tag, weigh, subtract the empty spool’s weight, sync — no typing, no guessing.
ESP32-S3 (16 MB flash, PSRAM), 3.5″ 480×320 colour touchscreen (LVGL) with full on-screen setup: WiFi picker + keyboard, calibration wizard, hardware self-test, OTA updates.
Battery powered (AXP2101 PMIC, charge state on screen), audio codec.
Precision weighing: HX711 + load cell, median + adaptive EMA filtering — tuned for a kitchen-scale feel.
8 firmware languages, 9-language web UI.
Live weight tracking — updates appear in real time in Tiger Studio and Tiger NFC Connect via Firestore.
Works with Tiger Studio’s container weight calibration so net filament weight stays accurate per container type.
It works offline. Brand and material identification comes from a database held in the device’s own flash, refreshed at most once a day — a tag lookup never waits on the network.
Cloud sync is optional. The scale is fully usable without an account.
Its own web UI, served from the device, mobile-friendly, live over WebSocket at 10 Hz — no app to install to drive it from a phone.
No binary blobs: everything compiles from source.

A TigerScale V3 in use on a workbench, a spool resting on it

On the bench: put the spool down, it identifies itself and weighs itself.

Building one

Not into electronics? A USB scale and a TigerPOD do the same job with nothing to wire or flash — the official no-electronics alternative.

The scale is a DIY build, and the steps people expect to be hard are not:

Print the enclosure. One .3mf Bambu Studio project with the plates already laid out — on MakerWorld. Open it in Bambu Studio or Orca and press Slice: nothing to orient, no supports to place.
Wire the components. Connect the load cell, HX711, speaker and both PN532 readers to the board following the wiring diagram below — the same pinout for either board variant.
Flash from your browser. The web installer always serves the current release; after that the scale updates itself over the air.

The parts are commodity:

Qty	Component	Where
1	Waveshare ESP32-S3-Touch-LCD-3.5B — 480×320 IPS touch (the -3.5 without the B works too)	-3.5B · -3.5
2	PN532 V3 NFC module — pin header and mode switch required	Amazon
1	5 kg load cell + HX711	Amazon
1	USB-C 4-pin cable + connector	cable · connector
1	Li-ion battery — optional, the scale runs on USB	Amazon
—	Dupont wires, M3 self-tapping screws	wires · screws
—	2× M4×30 and 2× M5×30 (load cell), 4× M2×6 (display)	any hardware shop
1	A small speaker	ships with the ESP32-S3 board

Waveshare ESP32-S3-Touch-LCD-3.5B board — **Both variants work, but they need different firmware.** Read the silkscreen: **-3.5B** or **-3.5**. The web installer asks which one you have; the wiring and the case are the same either way. Flash the wrong build and the scale starts up perfectly but never sees a tag, with nothing on screen to say why.

5 kg load cell and HX711 amplifier board — **Warning:** the load cell must have 2× M4 and 2× M5 tapped holes, and the HX711 board must be identical to the one shown — otherwise it will not fit in its designated slot.

Some links in this table are Amazon affiliate links: as an Amazon Associate, TigerTag earns from qualifying purchases, at no extra cost to you. It helps fund the open protocol. Buying the same parts anywhere else works exactly as well.

The full costed bill of materials lives in the repository.

Assembly

TigerScale V3 enclosure, front three-quarter view — Front three-quarter

TigerScale V3 enclosure, rear three-quarter view — Rear three-quarter

TigerScale V3 enclosure, rear three-quarter close-up — Rear three-quarter, close

TigerScale V3 enclosure, side elevation view — Side elevation

TigerScale V3 assembled, correct rear orientation — Scale position and orientation

PN532 reader mounted in its enclosure slot — PN532 seated in its slot

Wiring diagram

Interactive schematic in Cirkit Designer

Troubleshooting

No COM port detected for the ESP32-S3 in the web installer?

A driver might be missing for your system. Follow the driver install guide.

Yours to make and to sell

Anyone can manufacture and sell TigerScale hardware. No licence fee, no royalty, no registration. Build it, flash the official firmware, ship it.

The single condition for calling your product a TigerScale is running that official firmware unmodified, so every unit behaves identically inside the ecosystem. Fork it if you want to change it — and give the fork a different name. That is the whole of the deal.

Where it sits

flowchart LR
  SPOOL["Spool on the scale"] --> SCALE["TigerScale (ESP32)"]
  SCALE -- "live weight" --> CLOUD[("Your TigerSystem account<br/>(Firebase)")]
  CLOUD --> ST["Tiger Studio"] & CO["Connect"]

The story so far

Three generations, and the shape of the thing changed at each one:

	Reading	Screen	Board	Form factor
V1 — never released publicly	one PN532	mini OLED	ESP32	a spool holder: a central support passing through the middle of the spool
V2 — Tiger-Scale, MIT	2× RC522	0.96″ OLED	ESP32-WROOM, USB-powered	a flat scale
V3 — Tiger-Scale-V3, MIT	2× PN532	3.5″ colour touchscreen	ESP32-S3, battery	a flat scale, self-contained

The V1 already carried essentially the V2’s electronics — ESP32, mini OLED, an HX711 board with a 5 kg load cell — but a single reader, and a completely different body.

V3 is different hardware, not a firmware update. The two are not interchangeable: a V2 you already built keeps its own repository and keeps working. It is simply no longer developed.

All three are fully open source (MIT) on commodity parts — the living proof that an ESP32 and an NFC reader module (PN532 / RC522 class) are enough to build a TigerTag-reading device.

A USB scale and a TigerPOD, no electronics

A TigerPOD sitting on a DYMO scale, weighing a tagged spool

The official alternative for anyone who does not want to build a scale. A standard USB scale and a TigerPOD, both plugged into the computer, and Tiger Studio does the rest — nothing to solder, wire or flash.

Plug the scale into your computer over USB.
Set the TigerPOD on top of it — the Mini or the original.
Tare the scale, with the TigerPOD on it.
Open Tiger Studio.
Put a spool on the TigerPOD. It reads the spool’s chips and Tiger Studio opens its card.
The scale weighs it, and Tiger Studio updates the spool’s weight on its own.

Which scales work

The DYMO M5 — a USB HID postal scale, power/tare/hold buttons and a small LCD

Tiger Studio reads standard USB “HID Scale” devices (HID usage page 0x8D, usage 0x20): starting with the DYMO M5 and the rest of the DYMO M series (M10, M25… same protocol), and any compliant HID Scale, whatever the brand. The scale is third-party hardware, not a Tiger product; the setup around it is official and supported.

Protocol, validated on real hardware — 6-byte Scale Data Reports at ~1 Hz:

Byte	Meaning
`[0]`	report id `0x03`
`[1]`	status: 1 fault · 2 stable @ zero · 3 in motion · 4 stable · 5 negative · 6 over capacity
`[2]`	unit (HID PoS codes): `0x02` gram · `0x0B` ounce · `0x0C` pound
`[3]`	signed power-of-ten exponent applied to the raw value
`[4..5]`	weight, LE16 (LSB, MSB)

DYMO vendor id 0x0922; the M5 is pid 0x8009. Quirk: the very first frame right after a tare reports unit 0x00.

The DYMO M2 is not supported — it has no USB port at all, so there is nothing to connect to a computer. The protocol is beside the point.

Interactions

With	How
Firebase (account database)	Writes live weight to the user’s account
Tiger Studio / Connect	Display live weight; health monitoring