UWB Follow-Me System

Overview

Precision person-following using Ultra-Wideband (UWB) two-way ranging. Enables SaltyLab to follow Tee during outdoor EUC rides at 20-30 km/h.

Hardware

MaUWB ESP32-S3 (DW3000)

Vendor: Makerfabs
URL: https://www.makerfabs.com/mauwb-esp32s3-uwb-module.html
Price: $54.80 USD each
SKU: MAUWBS3CA1
Qty needed: 3 (1 tag + 2 anchors)

Specs

Parameter	Value
UWB Chip	Qorvo DW3000 + PA
MCU	ESP32-S3 (WiFi + BLE 5.0)
Co-processor	STM32 (TWR scheduling firmware)
Range	500m outdoor
Accuracy	±10cm
Max anchors	8 (auto-select nearest)
Max tags	64
Interface	AT commands via UART, USB
Display	0.96" OLED
Power	USB 5V, ~200-250mA active
Channels	UWB Ch5 (6.5 GHz) + Ch9 (8 GHz)
Apple U1	Interoperable (per Qorvo)

System Layout

[Tag - on Tee]          [Anchor A - left stem]     [Anchor B - right stem]
  MaUWB ESP32-S3          MaUWB ESP32-S3             MaUWB ESP32-S3
  18650 battery            USB → Orin Nano            USB → Orin Nano
  OLED shows range         ~25cm apart for bearing estimation

How It Works

Tag (Tee) and Anchors (bot) perform Two-Way Ranging (TWR) at ~10-100Hz
STM32 firmware handles time-slot scheduling (no signal conflicts)
ESP32-S3 reports range via AT commands over UART/USB
Two anchors spaced 25cm apart → TDoA gives bearing angle
ROS2 node publishes /uwb/target (distance + angle in base_link frame)
Fused with camera person detection for identity confirmation

Tag Battery (12hr runtime)

3000mAh 18650 cell (e.g., Samsung 35E)
TP4056 USB-C charger board
Mini boost converter to 5V
3D-printed enclosure with belt clip

Software Integration

ROS2 package: saltybot_uwb
Subscribes to anchor serial ports
Publishes: /uwb/target (geometry_msgs/PoseStamped)
Fused in person_follower_node as primary position source
Camera serves as secondary (identity confirmation + obstacle avoidance)

References

Makerfabs GitHub: https://github.com/Makerfabs/Makerfabs-ESP32-UWB-DW3000
MaUWB AT command docs: https://www.makerfabs.com/blog/post/mauwb-new-firmware-upgrade_v112
Gitea issue: #57