BU03-Kit Development Board (Hardware Section 2)
——AndyL
3. Functional Effectiveness Testing1. Quick Start TestUART 1
1. Connect a TypeC data cable to your PC, open a serial terminal tool, and press the reset button. If the terminal prints the expected boot messages, the reset button works properly.
2. Send the command AT; if you receive OK, the send/receive test passes.
USB
The USB port is the TypeC connector labeled USB on the BU03Kit, used for printing distance measurements and other info. It uses the STM MCU’s builtin USB driver. Windows and macOS usually won’t auto-install this driver, so you must manually install it.
UART2
Testing UART2 requires a USBtoTTL adapter. UART2 will output ranging data (covered in later sections).
Wiring for USBtoTTL adapter:
LED Flow Test
Connect to the TTL port and send:
AT+TESTLED=X
Response:
- OK — AT command succeeded
- ERR — AT command failed
Example:
- Send: AT+TESTLED=1
- Receive: OK
Distance Only (Zeropoint) & 1D Positioning
With one anchor and multiple tags, you get realtime distance measurements (no direction). Adding a second anchor lets you compute onedimensional positions along a line.
2D Positioning (3 Anchors)
Three anchors plus tags yield basic 2D positioning. If one anchor is blocked or interfered, loss of redundancy hurts accuracy. Ensure clear lineofsight between anchors and tags.
You only need any one module (anchor or tag) to stream positioning data via USB/UART/WiFi/Ethernet to a PC; other anchors just need power and will forward data wirelessly.
Improved 2D (4 Anchors)
Four anchors add redundancy: if one is blocked, the extra data preserves accuracy. Same lineofsight requirement and streaming setup applies.
3D Positioning (6+ Anchors)
Six or more anchors support largearea 2D or full 3D positioning, with robust redundancy under blockage. Same streaming and power requirements.
Common AT Commands
Setup
l Configure one BU03Kit as anchor, another as tag.
l Anchor’s OLED or USB port will display the current distance to the tag.
l Keep antennas unobstructed and tags off flat surfaces to minimize error.
l For higher precision, use the calibration command (below).
Ranging Steps
1. On Anchor (A):
AT+SETUWBMODE=0
AT+SETCFG=0, 1, 1, 1
AT+SAVE
2. On Tag (B):
AT+SETUWBMODE=0
AT+SETCFG=0, 0, 1, 1
AT+SAVE
Anchor’s OLED shows distance to Tag.
Observed without calibration:±20 cm fluctuation.
2D Positioning
Use three anchors and one tag.
After configuring all, open the TWR PC software, connect any anchor via USB, and view realtime 20 m range navigation and track display.
If USB isn’t recognized, restart software or replug the cable.
Place anchors ≥1.5 m high with clear lineofsight (tripods recommended).PDOA Algorithm: Ranging & Angle
Method A: PC Software (non-persistent)
1. Configure Anchor (A) and Tag (B):
AT+SETUWBMODE=1
AT+SETCFG=0, 1, 1, 1
AT+SAVE
AT+SETUWBMODE=1
AT+SETCFG=0, 0, 1, 1
AT+SAVE
2. Open PDOA PC software: add the tag, then move it—software shows angle A and distance D in real time. Anchor OLED shows the same.
Method B: ATbased Binding (persistent)
1. Same config as above.
2. Watch the anchor’s TTL output for the Tag ID, then bind it:
AT+ADDTAG=267F1313, 8834, 1, 64, 0
AT+SAVE
3. Anchor OLED shows distance D and angle A (range: –60° to 60°).
By combining BU03 UWB, Nordic nRF52832 BLE, and PDOA, the kit can interact with UWBequipped smartphones.
Under factory firmware (TWR mode):
- Tag: 318.2 mW
- Anchor: 487.3 mW
JS006C{"TWR":{
"a16":"4096",
"R":115,
"T":0,
"D":76,
"P":-123,
"Xcm":-57,
"Ycm":50,
"O":408,
"V":49152,
"X":0,
"Y":0,
"Z":0
}}Key fields: Xcm, Ycm → angle = arctan(Xcm/Ycm) × 180/π ≈ 23.62°
Example: Distance 0x38 → 56 cm; Angle 0xEFFFFFFF → –17°.
1. Download the autocalculation Excel template.
2. Place the tag at measured 1 m intervals, record actual vs. displayed distances in the spreadsheet; it outputs a linear coefficient, e.g.: y = 0.9924x – 317.68.
3. Send calibration command (retain other params):
AT+SETDEV=10, 16336, 1, 0.018, 0.642, 0.9924, -317.68, 0, 0
AT+SAVE
5. User Experience & Optimizations- Using one anchor and one tag with default firmware is very straightforward. After calibration, distance and angle measurements become accurate.
- Reading quicklychanging OLED data can be tricky; using the PC software is easier.
Recommended Improvements:
1. Replace BU03Kit MCU with lowpower STM32C/L series or an ESP32C/S (WiFi/BT) or NRF52832 (BLE) for greater flexibility.
2. Reduce unused onboard LEDs to save power; add a Libattery interface for portable, lowpower deployments.
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