Keyboard latency

I found this article on Hacker News: https://danluu.com/keyboard-latency/. Do we have any idea what the latency on a Model 01 is?

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@algernon wrote a bit about it on his blog. there are several relevant entries; I think this is the latest:

https://asylum.madhouse-project.org/blog/2017/08/07/turbo/

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Now that I’ve seen Dan’s latency methodology and some of his assertions about key debouncing, I’m…not super confident in his numbers.

I did some latency measurements last week. What I did was to instrument our firmware to toggle a pin on the Arduino each time it sent a USB packet. Then I measured the time from key actuation to USB packet. My numbers ran at around 9-14ms depending on whether a compute and data heavy LED effect was running.

Even accepting Dan’s assertion that we’d be looking at 4+ms from ‘finger starts to move’ to first actuation, I think we’re doing pretty good :slight_smile:

I think we should be able to get things pared down from there, but it hasn’t been a priority.

I can send the logic analyzer data from Saleae Logic to anyobody who’d like to look at my results.

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For anyone reading my posts and measurements: that’s the main loop time. It does not include debounce, nor transmitting the report to the host. It just measures the time spent in the loop() function, so the numbers I have will be lower than actual, full latency.

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