Force Haptic Feedback with LRA & Load Cell

By Dan Chen, August 7, 2020

You will need

Hardware

VLV041235L – Vibration, LRA
It can be any vibration motor, I picked this one because it gives you strong haptic feedback.

Learn more about LRA
https://www.precisionmicrodrives.com/vibration-motors/linear-resonant-actuators-lras/



I got my LRA from
https://www.digikey.com/product-detail/en/jinlong-machinery-electronics-inc/VLV041235L/1670-VLV041235L-ND/12323578

DRV2605L Haptic Motor Controller – Adafruit
https://www.adafruit.com/product/2305

Load Cell 5kgf was shown in the video
(Later I found out it requires too much force, so not recommended )
https://www.digikey.com/product-detail/en/te-connectivity-measurement-specialties/FX1901-0001-0010-L/223-1776-ND/6148942

Try this load cell instead
https://www.digikey.com/product-detail/en/loadstar-sensors/REB5-002M-S/2263-REB5-002M-S-ND/10673281



Microcontroller
Feather / Astar / Arduino M0 … take your pick

Software Library

Adafruit_DRV2605_Library – Haptic Driver / I2c
https://github.com/adafruit/Adafruit_DRV2605_Library


HX711 Arduino Library – Load Cell Amplifier HX711Library/ I2c
https://github.com/bogde/HX711/archive/master.zip

If you are using STM32, hardware i2c, change the pin number in the sketch. Example SAMD51, SCD: Pin 20, SCL: Pin 21

Optional OLED Display

I2C OLED Display: I am using

https://www.sparkfun.com/products/15890
OLED Library: Optional
https://github.com/olikraus/U8g2_Arduino
https://www.smart-prototyping.com/blog/Zio-Qwiic-1.5in-OLED-Display-Qwiic-Start-Guide

Assemble

Conclusion

Use Fast sensing Pressure sensor

The Load Cell that I was using was slow at reading the data, same as FSR. This cases the “force touch” feel a little delay. FSR could be slightly better or picking a better load cell setup will fix this issue.