2 layers50 × 56 mm Opentag, the printed circuit board in 3D

Opentag

Open-source UWB Device

Size: 50 × 56 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 40
Nets: 43
Pads: 126
Tracks, vias: 271, 38
Pours: 1
Routed: Yes
KiCad: KiCad 8.0 (file 20240108)
Created: 19 Mar 2024
Updated: 24 Sep 2026

Overview

Opentag is an open-source printed circuit board by open-tags, from the open-tags/opentag repository on GitHub, published under the MIT licence. It is a 2-layer board of 50 × 56 mm with 40 parts on 43 nets, routed with 271 tracks and 38 vias.

It is built around the DWM3000 and SK6812. Its parts include 9 diodes, 8 resistors, 6 capacitors, 3 connectors and 2 ICs. It belongs with the SAM D and SAM boards of this library.

Main components

README

README.md

opentag · early UWB prototype

Hardware, firmware, and an iOS app from the early opentags research project.

Historical R&D reference. This prototype predates opentag U1 and uses different hardware and firmware. For current products and setup guides, visit opentags and the documentation.

Hardware · Firmware · iOS app · Current ROS 2 source

KiCad 3D render of the historical opentag circuit board, showing its routing, mounting holes, connectors, and assigned component models
_{Historical prototype PCB · rendered directly from the KiCad board and its assigned 3D models}

Some components have no assigned 3D model and appear as bare footprints. Render details

Original exploded CAD view of the early opentag prototype, showing its enclosure, circuit board, battery, and screws
_{Original prototype · exploded CAD view}

Explore the prototype

The project explored ultra-wideband (UWB) ranging and iPhone interaction. These files preserve that development work; they are not a complete, validated product release.

Resource	What is included	Start here
Hardware	KiCad schematics and board layouts, component libraries, BOMs, and fabrication exports	KiCad project
Firmware	Arduino / PlatformIO experiments and bundled radio libraries	Build notes and missing dependencies
iOS	Xcode project based on Apple's Nearby Interaction accessory sample	iOS setup notes

Before building

Firmware dependencies are incomplete. The active PlatformIO target is xiaoble_adafruit_nrf52. The source includes niq.h and the configuration references NIQ libraries that are not included in this repository. A clean checkout is not ready to build; see the firmware notes.
The iOS app is experimental. Its setup notes require an iPhone with Apple's U1 chip and a compatible accessory. Apple's U1 chip is unrelated to the opentag U1 product name.
Hardware files record prototype revisions. Check the schematic, board revision, and firmware pin assignments together before fabrication or flashing.

Current opentags resources

opentags now builds tracking hardware and integration tools for robotics. Start with the website for current products, the documentation for setup, or the ROS 2 source for robot integration.

This repository's prototype files and license do not describe the hardware, firmware, or licensing of current products.

Questions and corrections

Use Issues for questions or corrections about this prototype. Include the board revision, toolchain, and relevant logs when reporting a build problem. For current product inquiries, contact hello@open-tags.com.

License

See the repository's MIT license. Bundled third-party components retain their own license notices, including the iOS sample and Adafruit nRFCrypto.

Category and platform

SAM D and SAM

Project files

Show this board on your page

https://pcbkit.io/boards/open-tags/opentag

The board's own page, for a message or a post.

Source

Repository: open-tags/opentag
Board file: Hardware/Hardware.kicad_pcb
Commit: 1196b5e
Homepage: open-tags.github.io
Licence: MIT

Parts

Qty	Value	Footprint	References
7	470	Resistor_SMD:R_0603_1608Metric	R4, R5, R6, R7, R11, R12, R13
6	LED	LED_SMD:LED_0603_1608Metric	D1, D2, D3, D4, D7, D8
4	Fiducial	Fiducial:Fiducial_1mm_Mask2mm	FID1, FID2, FID3, FID4
2	1u	Capacitor_SMD:C_0603_1608Metric	C3, C4
2	4.7u	Capacitor_SMD:C_0603_1608Metric	C7, C8
2	Conn_01x02_Socket	Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical	J4, J5
2	LOGO	LOGO	G*, G*
2	SK6812	LED_SMD:LED_SK6812_PLCC4_5.0x5.0mm_P3.2mm	D5, D6
2	TestPoint	TestPoint:TestPoint_Pad_D2.0mm	TP-5V1, TP-Battery1
1	.1u	Capacitor_SMD:C_0603_1608Metric	C6
1	1 Amp Fuse	Fuse:Fuse_0603_1608Metric	F1
1	10u	Capacitor_SMD:C_0603_1608Metric	C5
1	2.5k	Resistor_SMD:R_0603_1608Metric	R14
1	Battery_Cell	Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical	BT1
1	Conn_01x06_Socket	Connector_PinHeader_2.00mm:PinHeader_1x06_P2.00mm_Vertical	J2
1	DWM3000	RF_Module:DWM1000	DWM1
1	LED	Resistor_SMD:R_0603_1608Metric	D9
1	MCP73831-5-OT	Package_TO_SOT_SMD:SOT-23-5	U2
1	SW_SPST	opentags_library:SW_JS102011SAQN	SW1
1	Seeed Studio XIAO SAMD21	Seeed Studio XIAO Series Library:XIAO-nRF52840-Sense-14P-2.54-21X17.8MM	U3

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Questions

How big is the Opentag PCB?

It measures 50 × 56 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Opentag use?

40 parts, built around the DWM3000 and SK6812. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Opentag KiCad files?

From the open-tags/opentag repository on GitHub, at the commit this page was made from: the board is Hardware/Hardware.kicad_pcb and its schematic Hardware/Battery Tester/Battery Tester.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Opentag design in my own project?

Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).