UWB IOT Module V2

Revision History

Revision

Date (DD/MM/YYYY)

Author

Changes

1

04/08/2022

Hans

Initial release

2

11/08/2022

Hans

Fix in anchor module axes

1. Overview

The IOT UWB system is designed by Weston Robot for mobile robot applications. It has the following features:

  • 1 Anchor to Multiple Tags “pairing”

  • Distance Measurement Accuracy: ±5cm

  • Angular Position Accuracy: ±5°

  • Anchor Interface: ROS1, Windows/Ubuntu App

2. Specifications

2.1 Anchor Module

../../_images/uwb_v2_anchor.png

Port

Protocol

Function

Micro-usb

USB

communication interface

2.2 Tag Module

../../_images/uwb_v2_tag.png

Port

Function

Micro-usb

charging of battery

Button

ON/OFF Toggle

2.3 Communication

No. of Modules - Number of active tag modules.
Feedback Packet rate - Rate which Anchor sends a feedback packet.
Average Node Update Rate - Average rate which nodes are updated within the feedback packet.
Average Packet Loss - Percentage of packet loss between modules.

No. of Modules

Feedback Packet Rate

Avg. Node Update Rate

Average Packet loss

1

8.15 hz

8.15 hz

19%

2

9.3 hz

8.19 hz

18%

5

9.87 hz

8.14 hz

19%

10

9.77 hz

7.97 hz

20%

20

9.95 hz

7.68 hz

23%

40

10.03 hz

6.65 hz

34%

1. Hardware Setup

3.1 Startup and Operation

3.1.1 Anchor Module

  • Connect the module to the computer via a micro-usb cable.

  • Upon start up, you should see a solid blue led and flashing green led.

3.1.2 Tag Module

  • To switch on, press single press the button.

  • Upon start up, the 4 blue leds will light up, indicating battery level.

  • To switch off, quickly double press the button.

3.1.3 Operating Conditions

  • Each module should be upright and have their front (face with logo) facing each other for optimal communications setup

  • Horizontal and Vertical angles are according to the anchor module’s coordinate system (shown below)

../../_images/uwb_v2_anchor_coord.png

4. Software Setup

There are 2 ways to interface with the Anchor modules out-of-the-box.

  1. NAssistant (Windows or Ubuntu)

  2. ROS1 Driver

4.1 NAssistant

4.1.1 Getting NAssistant

NAssistant can be downloaded from this link: https://www.nooploop.com/en/download/

4.1.2 Setting up

  1. Connect the Anchor module to the computer.

  2. Connection should open automatically.

  3. Click on the button below to automatically identify tag protocol.

../../_images/nassistant_auto.png

4.1.3 Visualisation

  1. Data tab can be used to see information such as raw data and node IDs.

../../_images/nassistant_data.png

  1. Line tab can be used to observe changes in each variable.

../../_images/nassistant_line.png

4.2 ROS1 Driver

4.2.1 Setting up

The ROS1 driver can be found here: https://github.com/westonrobot/nlink_parser.
Follow the README guide on the github repo to setup the anchor for communication with tag modules.

4.2.2 Running

$ roslaunch nlink_parser iot.launch

  • Parameters

    Parameter

    Description

    Default

    port_name

    port to the anchor module

    “/dev/ttyUSB0”

    baud_rate

    baud rate of the module

    921600

  • Published Topics

    Topics

    Message Format

    Description

    /nlink_iot_frame0

    nlink_parser::IotFrame0

    Data from detected tags (<=10 tags)