Love to see open source hardware on HN. Great job with this one! If I were not overwhelmed with projects this one would be on my list.
SmartKnob – Haptic input knob with software-defined endstops and virtual detents
31–40 of 49 posts
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#32Earlier quoted context omitted.
Not to mention the cost of failure and iteration.
It's all relative. It has gotten at least an order of magnitude less expensive over the last 10-15 years- 3D printing, low cost PCB manufacturers, availability and cost of automated machine tools like CO2 laser-cutters. It has actually gotten to a point where often time is the most "expensive" component of hobby/open-source hardware projects- while the cost of CAD software has decreased (mostly due to competition and…
After many years of being a father of 3 active kids, you can remove the "often" in your sentence :-D
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#33Earlier quoted context omitted.
Designer here - I will admit that I just do this as a bit of a hobby and I'm not an EE, so I don't have a great answer for you, but generally speaking since this is a high resistance/low KV motor and there's only so fast you could spin it by hand realistically, I think the voltages you could generate that way shouldn't be so high as to cause damage in most cases. The TMC6300 datasheet does show it directly connected…
Thanks for the swift response! I've been interested in haptic feedback for a long time, but so far have not come across any general way to calculate the acceptable power dissipation for a given motor and driver circuit. Physical controls have so much to offer in ease-of-use, but the chief downside of them currently is that there is no easy 'two-way binding'.
Motors often run at high rpm and then shut off, coasting to a stop. I would expect any standard bldc controller circuit to be able to handle any potential generated by manual movements without difficulty.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#34These would be awesome for flight simming.
Being a sim racing guy, my initial thought was for brake bias / traction control / fuel map.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#35I have been looking for good-feeling large rotary encoders and this looks like the best option available. Having software-based detents means that they are perfectly aligned with the actual trigger, besides all the other flexibility demonstrated.
Sadly it's too big and costly to put into a dimmer switch, but maybe I'll get it as a general peripheral.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#36Earlier quoted context omitted.
Thanks for the swift response! I've been interested in haptic feedback for a long time, but so far have not come across any general way to calculate the acceptable power dissipation for a given motor and driver circuit. Physical controls have so much to offer in ease-of-use, but the chief downside of them currently is that there is no easy 'two-way binding'.
Motors often run at high rpm and then shut off, coasting to a stop. I would expect any standard bldc controller circuit to be able to handle any potential generated by manual movements without difficulty.
Many ESCs these days have a brake function, where they short-circuit two of the phases together, stopping the motor abruptly, too.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#37I absolutely love that this is open source hardware; there have been multiple circuits available on the web for this kind of peripheral, but nothing even approaching the level of polish that this has. If the designer happens to be here, I have a question regarding the circuit. Is there any protection against voltage produced by a user's rotation of the knob? The TMC6300 IC that the schematic shows is directly connect…
Designer here - I will admit that I just do this as a bit of a hobby and I'm not an EE, so I don't have a great answer for you, but generally speaking since this is a high resistance/low KV motor and there's only so fast you could spin it by hand realistically, I think the voltages you could generate that way shouldn't be so high as to cause damage in most cases. The TMC6300 datasheet does show it directly connected…
The UX in your project is fantastic, well done. The motor kicks to simulate clicks, for example, are a really nice touch. I still don't get how the PCB detects flexing, I'll just put it down to magic.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#38The flight/space sim community would love this.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#39Earlier quoted context omitted.
Tried searching by link before submission, it showed no results
the resubmit is worthwhile even for just the motor stocking updates
Exactly, last time it was posted here there were no motors available. I checked back a few times but there wasn't anything that worked. Glad to see there is a working option now.
Definitely a project I want to make when I have some free time.
Re: SmartKnob – Haptic input knob with software-defined endstops and virtual detents
#40I absolutely love that this is open source hardware; there have been multiple circuits available on the web for this kind of peripheral, but nothing even approaching the level of polish that this has. If the designer happens to be here, I have a question regarding the circuit. Is there any protection against voltage produced by a user's rotation of the knob? The TMC6300 IC that the schematic shows is directly connect…
Designer here - I will admit that I just do this as a bit of a hobby and I'm not an EE, so I don't have a great answer for you, but generally speaking since this is a high resistance/low KV motor and there's only so fast you could spin it by hand realistically, I think the voltages you could generate that way shouldn't be so high as to cause damage in most cases. The TMC6300 datasheet does show it directly connected…
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