BLDC Haptics Example

This example shows the use of the BldcHaptics component to drive a BLDC motor (such as a tiny gimbal motor) as a user input / output device that provides haptic feedback (such as might be used as a rotary encoder input).

How to use example

Hardware Required

This example requires a lot of hardware such as:

• Magnetic encoder chip (this example uses Mt6701)
• BLDC Motor Driver chip (this example was tested with the TMC6300 BOB dev board)
• Some mounting hardware to mount the motor, magnet, encoder, etc.

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NOTE: you MUST make sure that you run the example with the zero_electrical_offset value set to 0 (or not provided) at least once otherwise the sample will not work and could potentially damage your motor.

Currently, this is designed to be run on a TinyS3 connected to the motor driver and encoder via breadboard with the motor powered via a benchtop power supply at 5V.

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

idf.py -p PORT flash monitor

(Replace PORT with the name of the serial port to use.)

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

This example can be re-run (by modifying the code to change the selected DetentConfig from one of the predefined configurations or by making your own) to produce various behaviors. Additionally, at the end of each demo, it will play a haptic buzz / click using the motor.

For more information, see the documentation or the original PR: https://github.com/esp-cpp/espp/pull/60

Some examples:

coarse values strong detents (best with sound)

https://github.com/esp-cpp/espp/assets/213467/a256b401-6e45-4284-89c7-2dec9a49daa7

magnetic detents (best with sound)

https://github.com/esp-cpp/espp/assets/213467/ab1ace5c-f967-4cfc-b304-7736fdb35bcb

On / Off Strong Detents (best with sound)

https://github.com/esp-cpp/espp/assets/213467/038d79b1-7cd9-4af9-b7e8-1b4daf6a363a

Multi-rev no detents

https://github.com/esp-cpp/espp/assets/213467/2af81edb-67b8-488b-ae7a-3549be36b8cc

Troubleshooting

Make sure to run the example once with zero_electrical_offset set to 0 so that the motor will go through a calibration / zero offset routine. At the end of this startup routine it will print the measured zero electrical offset that you can then provide within the code, at which point it will not need to run the calibration routine.

You must run this calibration any time you change your hardware configuration (such as by remounting your motor, magnet, encoder chip).

Example Breakdown

This example is relatively complex, but builds complex haptic behavior using the following components:

• espp::Mt6701
• espp::BldcDriver
• espp::BldcMotor
• espp::BldcHaptics
• ESP-IDF's i2c peripheral driver

You combine the Mt6701 and BldcDriver together when creating the BldcMotor and then simply pass the BldcMotor to the BldcHaptics component. At that point, you only have to interface to the BldcHaptics to read the input position or reconfigure the haptics.