4 ms·

> I'm surprised by the section on including key travel time in the latency measures. Wasn't the Apple 2 keyboard about comparable in travel distance and resista

by kongin 5y ago

> I'm surprised by the section on including key travel time in the latency measures. Wasn't the Apple 2 keyboard about comparable in travel distance and resistance to today's typical mechanical keyboard switches? >>A major source of latency is key travel time. It’s not a coincidence that the quickest keyboard measured also has the shortest key travel distance by a large margin. The video setup I’m using to measure end-to-end latency is a 240 fps camera, which means that frames are 4ms apart. When videoing “normal" keypresses and typing, it takes 4-8 frames for a key to become fully depressed. Most switches will start firing before the key is fully depressed, but the key travel time is still significant and can easily add 10ms of delay (or more, depending on the switch mechanism). Contrast this to the Apple "magic" keyboard measured, where the key travel is so short that it can’t be captured with a 240 fps camera, indicating that the key travel time is < 4ms. Yeah, I don't get that either. It should be the time a key makes contact to the time the signal is sent. If I were to design that I would make an external trigger that connects to the solder pads of the key and start the timer on the logic analyser. I like my keys with a lot of travel and a good thunk when they send the signal. This would penalize them extensively for doing exactly what I want. I mean if you want fast keyboards capacitive key caps would be even faster, but I've yet to meet anyone who has replaced their keyboard with a tablet.

regularfry 5y ago
Because typing on a capacitive tablet would be tiring. You can't rest your fingers anywhere without registering a touch, so you lose all the benefits of a home row. You need to be able to distinguish between resting contact and a positive press, and capacitives would make that hard. Not impossible, but not easy either, and tablets today don't do it.
- kongin 5y ago
  Not sure what you're explaining? I'm just pointing out that their metric is extremely flawed and can be easily gamed by an inferior solution. Like the Apple Magic.
  - riversflow 5y ago
    I'm not seeing how its "gaming the metric" to include travel time of the key on a keyboard. Typing is ultimately a physical interaction with an interface, not just data transmission over a wire. Therefore, if we are measuring the latency of the input we must include physical travel time. Consider an extreme example, if each "key" used a control lever, like the type on a tractor or used to control thrust in an airplane, we'll just say 90 degrees with a radius of 8", with a significant amount of linear activation force(relative to a keyboard). It wouldn't matter if the device had response time that was virtually instant when you reached the activation point, the input latency of this system would be so significant as to be impractical for most typing tasks. If anything excluding travel time would be gaming the metric.
    - kongin 5y ago
      >I'm not seeing how its "gaming the metric" to include travel time of the key on a keyboard. Because if we remove travel time by using a capacitive keyboard you end up with something that is objectively a worse keyboard. Replacing the capacitors with strain gauges so you can rest your fingers on the home row without activating them results in an worse keyboard yet again. Any metric that when optimized produces an objectively worse product is a bad metric and optimizing a bad metric is gaming it.
      - pdpi 5y ago
        It’s not an “objectively worse product”. It’s a product that does well on some metrics (size, apparently latency) and does poorly on others (famously, durability). Then there’s the completely subjective aspect of what sort of feel you want from the keyboard — which is why Cherry has a bazillion different switch types (and why I have a tester set on my desk right now because I’m trying to decide on a new keyboard). Prioritising each of those is up to you. Your priorities are different from mine, and my preferences don’t make your keyboard of choice “objectively worse” overall.
      - riversflow 5y ago
        This is quite literally about as subjective as it gets. You like a thunk when you type, and there isn’t anything wrong with that, but other people really like short stroke keys, and they might even find the keyboard you described delightful, especially—I would imagine— if it was paired with a nice, timely audio queue and haptics. I know several people who absolutely loved the butterfly keyboards, and I found them a joy to type on in short bursts. However I, personally, have too heavy of hands/fingers for them and prefer ~80g actuation force so I can completely rest my fingers on the keys without activating them.
bee_rider 5y ago
I think you are right that there are good keyboards that would get penalized in this metric. But I'm not sure that it makes sense to try to improve the measurement system -- is is possible that this just isn't a very important measurement.

by kongin 5y ago

regularfry 5y ago

Because typing on a capacitive tablet would be tiring. You can't rest your fingers anywhere without registering a touch, so you lose all the benefits of a home row. You need to be able to distinguish between resting contact and a positive press, and capacitives would make that hard. Not impossible, but not easy either, and tablets today don't do it.

kongin 5y ago
Not sure what you're explaining? I'm just pointing out that their metric is extremely flawed and can be easily gamed by an inferior solution. Like the Apple Magic.
- riversflow 5y ago
  I'm not seeing how its "gaming the metric" to include travel time of the key on a keyboard. Typing is ultimately a physical interaction with an interface, not just data transmission over a wire. Therefore, if we are measuring the latency of the input we must include physical travel time. Consider an extreme example, if each "key" used a control lever, like the type on a tractor or used to control thrust in an airplane, we'll just say 90 degrees with a radius of 8", with a significant amount of linear activation force(relative to a keyboard). It wouldn't matter if the device had response time that was virtually instant when you reached the activation point, the input latency of this system would be so significant as to be impractical for most typing tasks. If anything excluding travel time would be gaming the metric.
  - kongin 5y ago
    >I'm not seeing how its "gaming the metric" to include travel time of the key on a keyboard. Because if we remove travel time by using a capacitive keyboard you end up with something that is objectively a worse keyboard. Replacing the capacitors with strain gauges so you can rest your fingers on the home row without activating them results in an worse keyboard yet again. Any metric that when optimized produces an objectively worse product is a bad metric and optimizing a bad metric is gaming it.
    - pdpi 5y ago
      It’s not an “objectively worse product”. It’s a product that does well on some metrics (size, apparently latency) and does poorly on others (famously, durability). Then there’s the completely subjective aspect of what sort of feel you want from the keyboard — which is why Cherry has a bazillion different switch types (and why I have a tester set on my desk right now because I’m trying to decide on a new keyboard). Prioritising each of those is up to you. Your priorities are different from mine, and my preferences don’t make your keyboard of choice “objectively worse” overall.
    - riversflow 5y ago
      This is quite literally about as subjective as it gets. You like a thunk when you type, and there isn’t anything wrong with that, but other people really like short stroke keys, and they might even find the keyboard you described delightful, especially—I would imagine— if it was paired with a nice, timely audio queue and haptics. I know several people who absolutely loved the butterfly keyboards, and I found them a joy to type on in short bursts. However I, personally, have too heavy of hands/fingers for them and prefer ~80g actuation force so I can completely rest my fingers on the keys without activating them.

bee_rider 5y ago

I think you are right that there are good keyboards that would get penalized in this metric. But I'm not sure that it makes sense to try to improve the measurement system -- is is possible that this just isn't a very important measurement.