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#smartknob#esp32#bldcmotor

DIY haptic input knob: BLDC motor + round LCD

scottbez1

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  • Recommended by 2 people: 2 on Hacker News.
  • Presented by Scott Bezek, hardware developer
  • Linked in the descriptionscottbez1/smartknob

Intermediate. Assumes working knowledge.

2.8M views4 years ago2 recommendations

HardwareSystems programmingEmbedded systemsElectronics

Scott Bezek demonstrates SmartKnob View, an open-source haptic input device using a brushless motor for software-defined detents.

Introducing the SmartKnob View: an open-source input device with software-configurable endstops, virtual detents, haptic touch feedback, and a round LCD. Since you can't feel the detents through the video, make sure to turn up the volume so you can at least hear them, particularly the fine-grained detents toward the end of the video. A brushless gimbal motor is paired with a magnetic encoder to provide closed-loop torque feedback control, enabling virtual endstops and detents. Internally, everything is powered by an ESP32, with a TMC6300 BLDC motor driver, HX711 strain gauge ADC, VEML7700 ambient light sensor, and more! I'll have a lot more to share about this project in the future, like a design and assembly overview, so make sure you're subscribed if you want to see more! And follow me on Twitter (@scottbez1) for mini-updates, like this demo of the PCB-mounted strain gauges: twitter.com/scottbez1/status/1499510448864915465 or a sneak-peak of the internals: twitter.com/scottbez1/status/1502335685918814212 Open source project: github.com/scottbez1/smartknob 🛒 Related hobby electronics items (affiliate links help support the channel, at no cost to you): Round 240x240 LCD module (GC9A01): amzn.to/3xDpafs (This is a breadboard-friendly module using the same circular LCD panel used in the SmartKnob - useful for prototyping. If you want just the raw LCD panel, see the BOM in the project GitHub for more info) Highly recommended soldering iron - TS100: amzn.to/3Olswd0 (I use the Ralim/IronOS firmware, and built a barrel jack extension cable with flexible silicone-insulated dual-core wire for better maneuverability) Load cell amplifier - HX711: amzn.to/3uS0b66 (This is a breadboard-friendly module for using the same HX711 load cell amplifier used in the SmartKnob for detecting force applied downward on the knob, along with the strain gauges below) Strain gauges BF350-3AA: amzn.to/3uQLSij (Strain gauges like these are used to measure the PCB flex to detect presses on the knob) If you liked this video/project and would like to support other cool projects, I'd love to have your sponsorship support on GitHub: github.com/sponsors/scottbez1/ This project was greatly inspired by @JesseSchoch 's video "Haptic textures and virtual detents" so definitely check that out too: youtube.com/watch?v=1gPQfDkX3BU

Why it's here

2 people recommend this

What people say. Highly recommended as an impressive showcase of open-source hardware and haptic feedback engineering.

laurenceion Hacker News • Recommends

On “Reverse-engineering my speakers' API to get reasonable volume control”

Hey OP - if your thinking about a smart knob with haptic feedback etc - check this open source project out that you can build yourself - its amazing: link Video demo here: link to this video

rzzzton Hacker News • Recommends

On “Ask HN: What Are You Working On? (June 2025)”

Vaguely related - two encoder wheel projects on YouTube that might interest you: - "Wireless High Resolution Scrolling is Amazing": link - "DIY haptic input knob: BLDC motor + round LCD": link to this video

ly3xqhl8g9on Hacker News • Mentions

On “Where have all the hackers gone?”

…ing on the screen 2, we want that feeling, silky smooth user experience which some companies spend billions to provide, but very few individuals can offer by themselves, examples would be something in the tier of Bartosz Ciechanowski 3, scottbez1 4, or Chris from Clickspring 5, for a more hardware bent. 1 link 2 link 3 link 4 link to this video 5 link…

scottbez1on Hacker News • Mentions

On “Ask HN: What's the coolest physical thing you've made?”

I made a rotary input device that provides software-defined "virtual" detents and end-stops, implemented using a BLDC gimbal motor. It can dynamically switch from completely smooth unbounded rotation, to having detents with configurable spacing and strength and "end-stops" that spring back if you try to rotate past them. link to this video It's got a round LCD on the front of the knob (wired and supported via the hollow shaft of the motor) and uses the flex of the PCB and strain gauge sensors (in the latest revision, simply SMD resistors whose resistance changes when stretched) to detect when the knob is pressed down. It's open source hardware and software - link HN folks might appreciate that it com…

yonatan8070on Hacker News • Mentions

On “Tesla Normal Operating Sounds”

This reminded me of the SmartKnob View I saw on YT a while back, it's a knob built on a burshless motor that's controlled to provide the user with software defined feedback like tactile clicks and end stops link to this video

croteon Hacker News • Mentions

On “Mercedes-Benz commits to bringing back physical buttons”

…Elgato Stream Deck3. And sure, the fact that slapping in a giant touchscreen lets them decouple UX design from physical controls is going to play a big role. But it is by far the laziest and least user-friendly way of doing so. If that's the best you can come up with, you probably shouldn't be doing UX design at all. 0: link 1: link 2: link to this video 3: link…

u/ziayakensin r/embedded • Mentions

Resources for learning I do embedded stuff as a hobby and I'm fully self taught. It takes so much effort and research when I start a new project and I often have trouble asking for help. I think my problem must be the way I ask questions and my lack of knowledge doesn't help. Anyways, I was wondering what resources you might recommended I could look into! In my current project I've come across multitasking and samorphics and FOC controll for brushless motors. I'm curious what more things I should research, I don't know what I don't know :p Ps. I'm making a haptic button with an LCD screen and it's going really well so far! Took inspiration from this guy's project:link to this video