Getting Started With the Radar Sensor
This page will tell you how to get started with the radar sensor. For information about the development of the sensor please see Radar Velocity.
This guide is for use with the BoSL Board rev 0.4.x, and Radar velocity sensor 0.1.x.
Contents
Uploading to the ATmega328PB
The ATmega328PB is the MCU which is used to interface with the sensor. Firmware can be uploaded to this MCU using the Arduino IDE. 0. Download the firmware File:Radar-velocity firmware rev1.6.2.zip
1. Connect the TTL pin block on the radar sensor to a USB- TTL converter. For specific wiring please refer to the table
| Radar Sensor | Cable | USB-TTL converter |
|---|---|---|
| WKE | Half Orange | - |
| TX | Brown | TX |
| RX | Blue | RX |
| 3V3 | Green | 3V3 |
| RST | Orange | RST |
| GND | Half Green | GND |
2. Open the firmware up in the Arduino editor and select the correct port number.
3. Make sure that the BoSL AVR boards have been added to the editor if not please see https://support.arduino.cc/hc/en-us/articles/360016119519-How-to-add-boards-in-the-board-manager and follow the steps with the board manager URL https://monash-bosl.github.io/BoSL-IDE-Core/package_bosl.com.au_index.json.
4. Select the BoSL Boards -> ATmega328PB (3.3V, 8MHz)
5. Click upload
6. The firmware should now upload to the radar velocity sensor
ATmega328PB firmware adjustables
- line 11: SWEEP_LENGTH. Set this value (in mm) to change the length of the scan interval. This measured along the line of sight of the sensor. Range 0 to 3800
- line 12: SWEEP_START. Set this value (in mm) to change the start distance of the scan interval. This is measured along the line of sight of the sensor. Range 240 to 1500 (recommended), 3000 (experimental)
Connecting to BoSL board
To connect the radar sensor to the BoSL board with the supplied logging code please see the table below:
| Radar Sensor | Cable | USB-TTL converter |
|---|---|---|
| WKE | Half Orange | - |
| TX | Brown | D3 |
| RX | Blue | D2 |
| 3V3 | Green | 3V3 |
| RST | Orange | D6 |
| GND | Half Green | GND |
BoSL logging firmware
Here is supplied firmware for a BoSL board to connect to a radar sensor and log the data to the web: File:BoSL logger radar 1.4.1.zip
BoSL logging firmware adjustables
- line 23: SITEID. Set this to a site ID you would like the upload to be identified with. Aim to keep this below 12 characters.
- line 24: LOGMODE. This controls the data recorded and uploaded. Please set to 5 for default behaviour associated with this guide.
Accessing and interpreting the data
To access the data please download the csv file with the SITE ID name from http://www.bosl.com.au/IoT/testing/databases/
The data and the column values are explained in this excel file File:Fine depth decode.xlsx. As per the excel file the velocity needs to be corrected as per the formula v -> v/cos θ, where θ is the uploaded installation angle. The excel file also decodes the fine depth into distances (line of sight) and amplitudes. One of the 4 measurements will typically be the water surface. We return the 4 strongest measurements for the depth as if there is a strong static reflection in the scene which is not the water surface (typically a metallic object) this will not mask the measurement of the water surface. To go from line of sight distance to water depth. The installation height H needs to be known, for a line of sight distance l the depth is d = H - l/sin θ where θ is the uploaded installation angle.
Flashing the STM32G071CB
The STM32G071CB on the XM132 is responsible for controlling the A111 radar sensor and performing digital signal processing. This should already come pre-flashed with firmware. Instructions on how to do this are coming soon... If you have access to a UART port on the STM32 and can connect this to a computer then simply using:
py.exe -m stm32loader -p<comport> -b921600 -e -w -v <path to binary>
will flash the STM32
