EYE on NPI: Vybronics' Rectangular LRA Vibration Motor #EYEonNPI @vybronics @digikey @adafruit
Channel: Adafruit Industries
Date: 2023-06-08

This week's EYE ON NPI passes the vibe check - it's Vybronics' Rectangular LRA Vibration Motor (https://www.digikey.com/en/product-highlight/v/vybronics/rectangular-lra-vibration-motor) and friends - a series of linear resonant actuators, AKA LRA, used to create vibration/haptic feedback.

Haptics (https://en.wikipedia.org/wiki/Haptic_technology) were first used in airplanes - where originally there was a mechanical connection between the pilot controls and the plane steering. That is, when turning or tilting the yoke, it would mechanically control any flaps (https://en.wikipedia.org/wiki/Aircraft_flight_control_system). However, that means that the pilot would have to be strong enough to move the flaps while also keeping track of all the different controls needed - a recipe for disaster because a tired or confused pilot could make a catastrophic mistake! So, instead, the control of aircraft turned to hydro-mechanical and then servo-electrical. You might see the same on modern cars: instead of the steering wheel directly controlling the tire angle, it now send a signal that is interpreted by motors that do the actual movement, also known as Drive by wire. (https://en.wikipedia.org/wiki/Drive_by_wire)

The trade-off with drive or fly-by-wire is that there's less need for strength and speed by the person in the cockpit - but they do lose the mechanical feedback that would normally be fed back through the mechanical linkages. That feedback is important because it allows you to feel when something might be blocking or fighting against the motion - in planes you can tell the airspeed and the craft's stress level. Sure you can put this information in a gauge of some sort but it requires the operator to look and interpret a number when the feeling is more intuitive. Thus the invention of force feedback or...haptics!

Haptics have been tirelessly used in automotive and aircraft for decades, when in the 90's they had a bit of a resurgence as part of VR interfaces. If you're in a 3D rendered virtual world, you want to feel when you bumped into something or grabbed an item successfully. For gaming, an early form of 'play by wire' we've moved from the 1994 Aura Interactor (https://en.wikipedia.org/wiki/Aura_Interactor) to being included in almost every game controller, like the 1997-released N64 Rumble Pak (https://en.wikipedia.org/wiki/Rumble_Pak) and Playstation DualShock (https://en.wikipedia.org/wiki/DualShock) as vibrational feedback when moving or taking damage. 

Mobile devices are also big users of haptic feedback - originally as vibration alert for 'silent mode' - but now also for typing and UX feedback. For vibration feedback, a basic ERM motor such as the Vybronics VZ43FC1B5640007L (https://www.digikey.com/en/products/detail/vybronics-inc/VZ43FC1B5640007L/12323649) will do fine - turn it on to cause a vibration that can be detected even when the phone is in a bag or pocket. 

But if you want to have 'sharper' feedback, these ERMs aren't as good because they take time to turn on and get up to speed. So they're good for big motion but not quick motion. That's when you want to use LRAs - Linear Resonant Actuators. (https://www.digikey.com/en/product-highlight/v/vybronics/rectangular-lra-vibration-motor)

Vybronics makes a wide range of LRA vibration motors (https://www.digikey.com/en/supplier-centers/jinlong-machinery) in addition to their wide range or ERM's. You can select from different sizes - larger ones will of course have a stronger feedback response, but will require more energy and size. ERM's are really easy to drive: provide a positive DC voltage and the motor starts moving. LRA's are harder to control, you will need an AC waveform to kick-start the resonant motion. (https://www.vybronics.com/lra-assembly-drawing) 

Our favorite driver is the TI DRV2605 (https://www.digikey.com/en/products/detail/texas-instruments/DRV2605LDGSR/5014144) which we even have a breakout board (https://www.digikey.com/en/products/detail/adafruit-industries-llc/2305/5356831) to make it easy to connect up to a Vybronics LRA. The DRV2605 even comes with a wide range of built-in waveform actions (https://www.ti.com/lit/ds/symlink/drv2605.pdf) to make integration very easy. Vybronics also has some examples of how to mount their motors with PCB contacts to allow the motor to vibrate within a cavity.(https://www.vybronics.com/mounting-with-spring-contacts)

Vybronics' Rectangular LRA Vibration Motors such as the VLV152564W (https://www.digikey.com/en/products/detail/vybronics-inc/VLV152564W/19203005) will make the vibe right in your product that requires tactile haptic feedback to improve your user experience. With their small cases and high strength, they'll turn glass touchscreens and capacitive touch buttons into something that feels like a mechanical control surface. Order today and DigiKey will ship your motor instantly so that you can be tick-tack-bzzt'ing your way to a haptic cyber-future by tomorrow afternoon.