Now I am testing a new prototype.
In this iteration, I am trying some new (but small) ideas:
- Placing 1QAZ keys along with other character keys.
1QAZ keys along with Tab key (see a past post of this blog) is good for keyboard shortcuts, but not very good for typing.
So far, I feel hard to stabilize my pinky finger on the keyboard. I am leaning toward rejecting this idea. - Placing a rotary switch for default layer selection.
I myself do not use default layer selection (I use just MO(n)), but I am absolutely disagree with any non-tangible states in a keyboard. All states in a keyboard should be tangible. CapsLock key is evil because it depends on LED. You must see LED or screen to know the CapsLock state. This is not tangible. A rotary switch state is tangible, i.e. you can know the state without looking anything.
So far, this idea looks good. - PIN/function keypad with Fn key.
In the last iteration, I tested double action switches for number/function keypad. Deep press makes number key signal and shallow press/release makes function key signal. The results are complicated. A small number/function keypad is great. Especially good for entering PIN code. But double action switch is a bad idea.
So in this iteration, I choose normal tactile switches and utilize Fn key. Number keys are in Fn layer because PIN code is 4 to 6 digits and we can keep Fn key down while entering the digits.
In this iteration, I choose Kailh Saker Mini switch. This is a novel Choc V2 variation and the total travel is just 1.8 mm. I feel that the travel is good, but the actuation force 37 gf is a bit weak.
I placed a scroll slider on the left edge. So far I feel the place is good enough. Sometimes the scroll slider is strikingly valuable, but that doesn't happen very often. There are a lot of work to make the slider excellent, e.g. macOS capability and zoom (two-finger) feature. I am still uncertain whether it is worth the effort or not.
I am preparing the product version too. For the product version, I designed a mainboard with built-in USB 2.0 hub:
A Type-A port on the top of the case. Two downstream ports, Type-A and Type-C, on the back.
USB 2.0 hub is a den of secrets of the field. You can easily find the secrets if you are interested in USB 2.0 hub, but in many cases, you cannot find the reason unless you are an insider of the field. I am an outsider, and still wonder why there is no reversible Type-A port component on the market.
Today I'd like to tell you an easy secret: All bus-powered USB 2.0 hubs claim "I am a self-powered hub" to the PC.
On Windows, get USB Device Tree Viewer and look at your USB 2.0 bus-powered hubs with the viewer. You will find "Self powered : yes" in "Summary" section in all your bus-powered hubs. Why? This is not a bug of the viewer or the hubs.
- All USB 2.0 devices claim their maximum demand current (MDC) to the PC.
- MDC is maximum, not usual. For example, a common USB flash claims 300 mA. But 300 mA is just while reading/writing.
- According to the USB 2.0 specification, a bus-powered hub cannot run over 100 mA MDC devices on its ports. This limitation is forced by OS of the PC. If a (honest) bus-powered hub port accepts the USB flash, the OS shows an error message and disables the USB flash.
- The limitation is too much for most of us. For medical or aerospace, the limitation is reasonable. But in most cases, we do not use MDC of two devices at the same time. We want to just rely on overcurrent protection in somewhere, and see an error message when the protection breaks the current.
- To bypass the limitation, almost all USB 2.0 bus-powered hubs claim "I am a self-powered hub" to the PC.
I did not know the secret. My prototype hub claims "I am a bus-powered hub" and it is almost useless. I will fix the issue in the product, so, it will claim "I am a self-powered hub" to the PC.
