- Tag: MPU6050 on shared I2C bus (SDA=4, SCL=5, addr 0x68)
- Accel ±8g, gyro ±500dps, read at 50Hz
- Fall detection: freefall+impact or sudden >3.5g
- Fall triggers auto e-stop (ESP-NOW broadcast)
- OLED shows tilt bar + accel magnitude
- New ESP-NOW packet types: MSG_IMU (0x40), MSG_FALL (0x50)
- IMU broadcast at 10Hz via ESP-NOW
- Anchor forwards +IMU: and +FALL: lines to Jetson serial
- ROS2 uwb_driver publishes sensor_msgs/Imu on /uwb/imu
- .gitignore for .pio build dirs
Anchors:
- Broadcast own range via ESP-NOW after each TWR cycle
- Receive other anchor's range via ESP-NOW, print as +RANGE on serial
- Either anchor's serial port gives Orin BOTH ranges (only need 1 USB/UART)
Tag:
- Receives ESP-NOW from both anchors
- Updates display with both A0 + A1 distances regardless of DW1000 pairing
- Solves the 'only sees A0' display issue
Each anchor only runs DW1000Ranging during its 50ms time slot.
Anchor 0 responds in even slots, anchor 1 in odd slots.
Prevents RF collisions that caused wild range readings.
- MODE_LONGDATA_RANGE_ACCURACY → MODE_LONGDATA_RANGE_LOWPOWER (both anchor+tag)
- Add delay(1) in tag loop to prevent tight-loop when no anchors respond
- ACCURACY was unnecessary and kept DW1000 radio hot
Tag firmware (esp32/uwb_tag):
- SSD1306 128x64 OLED: shows distance, anchor ranges, RSSI bars, link status
- ESP-NOW broadcast: sends range/heartbeat/estop packets (20 bytes, peer-to-peer)
- Emergency stop: GPIO 0 (BOOT), active LOW, 10Hz TX while held, 3x clear on release
- Display updates at 5Hz, ranging still at 20Hz round-robin
- Added Adafruit SSD1306 + GFX lib_deps to platformio.ini
Anchor firmware (esp32/uwb_anchor):
- ESP-NOW receiver: captures tag packets via ISR ring buffer
- Forwards to Jetson serial as +ESPNOW: and +ESTOP: lines
- E-STOP packets get priority immediate output
- Zero impact on existing TWR ranging loop
For Makerfabs ESP32 UWB Pro with Display (DW3000 chip).
Anchor firmware for Makerfabs ESP32 UWB Pro (DW3000 chip). Two anchors
mount on SaltyBot (port/starboard), USB-connected to Jetson Orin.
- DS-TWR responder: Poll→Resp→Final with ±10cm accuracy
- Streams +RANGE:<id>,<mm>,<rssi_dbm> on Serial 115200
- AT command interface: AT+RANGE?, AT+RANGE_ADDR=, AT+ID?
- ANCHOR_ID 0/1 set at build time (env:anchor0 / env:anchor1)
- PlatformIO config for Makerfabs MaUWB_DW3000 library
- udev rules for /dev/uwb-anchor0 /dev/uwb-anchor1 USB symlinks
- Pin map: SCK=18 MISO=19 MOSI=23 CS=21 RST=27 IRQ=34
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
