MagicWand < IoT_Course_English

---+ The Magic Wand Example

In the Magic Wand example a "magic wand" is used to paint digits into the air. An accelerometer and gyroscope is used to record the movement and from the acceleration and gyroscope data the gesture is reconstructed.
---++ The hardware

In order to get a stable hardware configuration we use the [[https://cdn-shop.adafruit.com/product-files/5477/esp32-s3_datasheet_en.pdf][ESP32-S3FH4R2]] CPU in conjunction with an [[https://content.arduino.cc/assets/st_imu_lsm6ds3_datasheet.pdf][LSM6DS3 ]]accelerometer and gyroscope module. The !LSM6DS3 is mounted on a !WeMos D1 mini prototype board, which in turn is connected to the CPU via the triple base backplane. The backplane is attached to the magic wand with screws.

| <img alt="img_0115.png" height="800" src="%ATTACHURL%/img_0115.png" title="img_0115.png" width="533" /> |
| The magic wand<br />On top: the !LSM6DS3 accelerometer and gyroscope<br />at the bottom: the ESP32-S2FH4R2 CPU |

| <img alt="accelerometer_interface.png" src="%ATTACHURL%/accelerometer_interface.png" title="accelerometer_interface.png" /> |
| Interfacing the !LSM6DS3 to the !WeMos D1 mini bus |
The magic wand example is the only one for which no ESP32 version can be found on the internet. The version available uses an Arduino Nano 33 !BLE sense board with a !LSM9DS1 accelerometer, gyroscope and magnetometer. This chip is substantially more expensive that the !LSM6DS3, that misses the magnetometer, which however is not needed to run the example.

The !LSM6DS3 has an !I2C as well as an SPI interface. The connections are shown in the table below. The driver only uses the !I2C interface but could be easily extended to support SPI as well.

|  *LSM6DS3*  |  *WeMos D1 D pin*  |  *GPIO on !ESP32S3FH4R2*  |
|  3V3  |  3V3  | |
|  GND  |  GND  | |
|  SCL  |  D5  |  GPIO 12  |
|  SDA  |  D6  |  GPIO 13  |
|  CS  |  D7  |  GPIO 11  |
|  SA0  |  D8  |  GPIO 10  |
|  DCS  |  D1  |  GPIO 36  |
|  INT2  |  D2  |  GPIO 35  |
|  INT1  |  D3  |  GPIO 18  |
---++ The software

The software consists of several parts:
   * a [[LSM6DS3 readout]] program acquiring the acceleration and gyroscope values from the !LSM6DS3
   * a [[data conversion]] program taking the raw data and extraction stroke positions
   * The stroke positions are [[rasterized]] before using them as
   * input to the pre-trained neural network model
-- %USERSIG{UliRaich - 2023-12-18}%
---++ Comments

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Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
png	accelerometer_interface.png	r1	manage	579.5 K	2023-12-18 - 13:54	UliRaich
png	img_0115.png	r1	manage	647.5 K	2023-12-18 - 13:55	UliRaich

This topic: IoT_Course_English > WebHome > TinyML > MagicWand
Topic revision: r2 - 2023-12-18 - UliRaich