111 lines
4.6 KiB
Markdown
111 lines
4.6 KiB
Markdown
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# Wi-Fi FTM Initiator Arduino Example
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This example demonstrates how to use the Fine Timing Measurement (FTM) to calculate the distace from the Access Point and the device. This is calculated by the Wi-Fi Round Trip Time (Wi-Fi RTT) introduced on the [IEEE Std 802.11-2016](https://en.wikipedia.org/wiki/IEEE_802.11mc) standard.
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This example was based on the [ESP-IDF FTM](https://github.com/espressif/esp-idf/tree/master/examples/wifi/ftm). See the README file for more details about on how to use this feature.
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Some usages for this feature includes:
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* Indoor positioning systems.
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* Navigation.
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* Device Location.
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* Smart Devices.
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* Alarms.
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# Supported Targets
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Currently, this example supports the following targets:
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| Supported Targets | ESP32-S2 | ESP32-C3 |
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| ----------------- | -------- | -------- |
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## How to Use Example
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In order to use the FTM, you will need a Responder or Wi-Fi router with FTM capabilities. If you don't own one, you can use a second ESP32-S2 or ESP32-C3 to simulate one.
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See the **Responder** example to prepare the environment.
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* How to install the Arduino IDE: [Install Arduino IDE](https://github.com/espressif/arduino-esp32/tree/master/docs/arduino-ide).
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### Configure the Project
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To configure this project, you can change the following configuration related to FTM feature:
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```c
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// Change the SSID and PASSWORD here if needed
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const char * WIFI_FTM_SSID = "WiFi_FTM_Responder"; // SSID of AP that has FTM Enabled
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const char * WIFI_FTM_PASS = "ftm_responder"; // STA Password
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// FTM settings
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// Number of FTM frames requested in terms of 4 or 8 bursts (allowed values - 0 (No pref), 16, 24, 32, 64)
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const uint8_t FTM_FRAME_COUNT = 16;
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// Requested time period between consecutive FTM bursts in 100’s of milliseconds (allowed values - 0 (No pref) or 2-255)
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const uint16_t FTM_BURST_PERIOD = 2;
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```
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* Change the Wi-Fi `SSID` and `PASSWORD` as the same as the Responder/Router.
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* Change `FTM_FRAME_COUNT` with the number of frames requested to the Responder.
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* Change `FTM_BURST_PERIOD` with the time between each FTM burst.
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To see more details about FTM, please see the [ESP-IDF docs](https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/network/esp_wifi.html).
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#### Using Arduino IDE
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To get more information about the Espressif boards see [Espressif Development Kits](https://www.espressif.com/en/products/devkits).
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* Before Compile/Verify, select the correct board: `Tools -> Board`.
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* Select the COM port: `Tools -> Port: xxx` where the `xxx` is the detected COM port.
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#### Using Platform IO
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* Select the COM port: `Devices` or setting the `upload_port` option on the `platformio.ini` file.
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## Log Output
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Expected log output:
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```
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ESP-ROM:esp32s2-rc4-20191025
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Build:Oct 25 2019
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rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
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SPIWP:0xee
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mode:DIO, clock div:1
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load:0x3ffe6100,len:0x4b0
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load:0x4004c000,len:0xa6c
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load:0x40050000,len:0x25c4
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entry 0x4004c198
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Connecting to FTM Responder
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.....
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WiFi Connected
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Initiating FTM session with Frame Count 16 and Burst Period 200 ms
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FTM Estimate: Distance: 0.13 m, Return Time: 0 ns
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FTM Estimate: Distance: 0.13 m, Return Time: 0 ns
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FTM Estimate: Distance: 0.13 m, Return Time: 0 ns
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FTM Estimate: Distance: 0.00 m, Return Time: 0 ns
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...
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```
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## Troubleshooting
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***Important: Make sure you are using a good quality USB cable and that you have a reliable power source.***
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* **Programming Fail:** If the programming/flash procedure fails, try reducing the serial connection speed.
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* **COM port not detected:** Check the USB cable and the USB to Serial driver installation.
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If the error persist, you can ask for help at the official [ESP32 forum](https://esp32.com) or see [Contribute](#contribute).
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## Contribute
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To know how to contribute to this project, see [How to contribute.](https://github.com/espressif/arduino-esp32/blob/master/CONTRIBUTING.rst)
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If you have any **feedback** or **issue** to report on this example/library, please open an issue or fix it by creating a new PR. Contributions are more than welcome!
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Before creating a new issue, be sure to try the Troubleshooting and to check if the same issue was already created by someone else.
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## Resources
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* Official ESP32 Forum: [Link](https://esp32.com)
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* Arduino-ESP32 Official Repository: [espressif/arduino-esp32](https://github.com/espressif/arduino-esp32)
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* ESP32-S2 Datasheet: [Link to datasheet](https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf)
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* ESP32-C3 Datasheet: [Link to datasheet](https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf)
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* Official ESP-IDF documentation: [ESP-IDF](https://idf.espressif.com)
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