UWB Localization Feather

Description

The Ultra-WideBand Feather incorporates the Decawave DWM1000 module and an ATSAMD21 ARM Cortex M0 into the Adafruit feather form-factor. The DWM1000 module is an IEEE802.15.4-2011 UWB compliant wireless module capable of precision indoor positioning and high data rates, making this board perfect for robotics projects where localization is required.

Features:
– Decawave DWM1000 for precision tracking
– ARM Cortex M0 for fast & powerful applications
– Adafruit Feather compatible to integrate with a wide existing ecosystem
– SWD interface for programming and debugging applications
– USB-C connector
– Intergrated LiPo battery charger

I maintain all projects on my site Prototyping Corner, so check there for updates on this project https://prototypingcorner.io/projects/uwb-feather

Details

Design

As mentioned in the introduction, the UWB Feather consists of an ATSAMD21 ARM Cortext M0+ for the brains and a Decawave DWM1000 module for the ultra-wide band wireless, in the feather form-factor. The design is relatively simple consisting of 20 BoM items on a 2-layer PCB. Pinout is Adafruit M0 Feather compatible

LiPo charging is handled by the MCP73831 single-cell, fully integrated charge management controller. Battery voltage can be monitored on D9, however is access to all the IO is required, JP1 can be cut to free up this pin. 3.3 volt regulation is preformed by the AP2112K-3.3 low dropout linear regulator, providing up to 600mA.

Pinout is fully compatible with the Adafruit M0 feather line for easy code portability. The DWM1000 IO lines are connected to the SPI bus and digital pins 2, 3 & 4 for RST, IRQ & SPI_CS respectivly (which are not exposed via the header). D13 is also connected to the onboard LED, as is standard among many Arduino-compatible boards.

Programming can be preformed over the SWD header or via USB if loaded with a corresponding bootloader such as the uf2-samdx1 from Microsoft. See firmware for more.

Note on V1.0: There is an issue with the USB-C connector on version 1 of this board. The footprint I used did not include the cutout required for the cutout mounting method of this component.

Version 1.1 will include a fix for this as well as adding a micro-b connector for those who want it. See version 1.1 considerations below.

The DWM1000 has a One Time Programmable (OTP) user programmable memory for storing calibration information (see 1.6 in the datasheet). To program this region the VDD3V3 pins may need to be raised to 3.8 volts temporarily. To do this JP2 can be cut and a separate power supply can be connected to selectively boost the power to the module.

Version 1 Board Renders

Bill of Materials

BoM items are all available from DigiKey and are plentiful in supply. Total BoM cost was $60 AUD for 1 quantity, however further optimization can shave a few dollars off this.
CSV version of this table can be found in the project repository.

Manufacturer Part Number	Manufacturer	Digi-Key Part Number	Customer Reference	Quantity	Description
DX07B024JJ3R1600	JAE Electronics	670-2963-1-ND	J1	1	CONN RCP USB3.1 TYPEC 24P SMD RA
S2B-PH-SM4-TB(LF)(SN)	JST Sales America Inc.	455-1749-1-ND	CN1	1	CONN HEADER SMD R/A 2POS 2MM
KMR241GLFS	C&K	401-1431-1-ND	SW1	1	SWITCH TACTILE SPST-NO 0.05A 32V
AP2112K-3.3TRG1	Diodes Incorporated	AP2112K-3.3TRG1DICT-ND	U4	1	IC REG LINEAR 3.3V 600MA SOT25
MBR120VLSFT1G	ON Semiconductor	MBR120VLSFT1GOSCT-ND	D2	1	DIODE SCHOTTKY 20V 1A SOD123FL
ATSAMD21G18A-MU	Microchip Technology	ATSAMD21G18A-MU-ND	U1	1	IC MCU 32BIT 256KB FLASH 48QFN
20021221-00010C4LF	Amphenol ICC (FCI)	609-3700-1-ND	J4	1	CONN HEADER SMD 10POS 1.27MM
DWM1000	Decawave Limited	1479-1002-1-ND	U3	1	RF TXRX MODULE 802.15.4 CHIP ANT
MCP73831T-2ATI/OT	Microchip Technology	MCP73831T-2ATI/OTCT-ND	U2	1	IC CONTROLLR LI-ION 4.2V SOT23-5
RC0603FR-075K1L	Yageo	311-5.10KHRCT-ND	R1, R2, R6	3	RES SMD 5.1K OHM 1% 1/10W 0603
SML-D12D8WT86	Rohm Semiconductor	511-1577-1-ND	D1	1	LED ORANGE DIFFUSED 0603 SMD
150060BS55040	Würth Elektronik	732-12013-1-ND	D5	1	LED BLUE DIFFUSED 0603 SMD
RC0603FR-071KL	Yageo	311-1.00KHRCT-ND	R4	1	RES SMD 1K OHM 1% 1/10W 0603
RC0603FR-07100KL	Yageo	311-100KHRCT-ND	R5, R3	2	RES SMD 100K OHM 1% 1/10W 0603
TMCJ0J106MTRF	Vishay Sprague	718-2355-1-ND	C5, C7, C8	3	CAP TANT 10UF 20% 6.3V 0603
RC0603FR-0710KL	Yageo	311-10.0KHRCT-ND	R10	1	RES SMD 10K OHM 1% 1/10W 0603
TMCJ1C105MTRF	Vishay Sprague	718-2362-1-ND	C1, C4, C6, C9	4	CAP TANT 1UF 20% 16V 0603
RC0603FR-07330RL	Yageo	311-330HRCT-ND	R9	1	RES SMD 330 OHM 1% 1/10W 0603
CC0402FRNPO9BN150	Yageo	311-1642-1-ND	C2, C3	2	CAP CER 15PF 50V C0G/NPO 0402
FC-135 32.7680KA-A0	EPSON	SER4077CT-ND	Y1	1	CRYSTAL 32.7680KHZ 12.5PF SMT

Hardware Version 1.1 Considerations

There are a number of changes required for a board that would be put into production as nobody gets it right the first time,...

Project Logs

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New boards & panel

Jed Hodson • 01/29/2020 at 11:11 • 0 comments

New boards made and assembled. Now available at shop.prototypingcorner.io

Finalized Rev 1.1

Jed Hodson • 01/07/2020 at 07:44 • 0 comments

Finished routing V1.1 boards and made some other minor changes such as reduced BoM from 20 to 17 unique components, fixed some minor schematic issues and cleaned up the silkscreen. V1.1 changes merged into master branch in the repository. I also changed the license of the board to the CERN OHL v1.2.

Next up: panelization and test jig

Revision 1.1 Update

Jed Hodson • 01/06/2020 at 12:48 • 0 comments

Schematic for Version 1.1. Issues with first boards fixed and I took the opportunity to make a few other changes. The board file is still incomplete (fully routed, just needs a little tidying up) and I need to update the BOM - will finalize tomorrow.

Changes:

- Changed USB-C connector

- Added pull-up resistor on DWM1000 IRQ line

- Rerouted with larger trace widths (10mil)

- Enlarged test point footprint and changed exposed pins: USB D+ and D- instead of CC1&2, removed D2, D3 and replaced with SWD for programming

- Reduced wire protrusion around antenna

- Replaced D13 and charge indicator for RGB led and connected to unused pins on M0

- Changed the charge controller from MCP73831 to the MCP73832 and connected the STAT pin to an unused pin on the M0. Now it is possible to detect when the battery is charging in software however controlling the charge LED (RGB LED) will need to be done in software.

- Connected BATT_V to unused analog pin (instead of D9)

What these changes mean:
- The USB-C connector will actually fit on the board.
- Board is now better suited to going in a test jig.
- All exposed header pins are fully available IO (no shared lines)
- There's an RGB LED and charge detection is now more flexible.

Changes to the pins will mean I will need to create a custom bootloader based off UF2, however I am much more happy with the board design and its flexibility. Intermediate changes are in the GitHub repo under the version-1.1 branch.

Discussions

UWB Localization Feather

Description

Details