The Raspberry Pi behind the TV has a monitor attached and no keyboard. One Wi-Fi password needs to go into it. The keyboard that would do the job is in the next room, under a stack of paper. It also wants two AA batteries.
The phone in your hand can take that job instead. Dotori Bluetooth Keyboard turns it into a standard Bluetooth keyboard and trackpad. The receiving device needs no driver and no companion app. This post covers the pairing, the two orientations, and the calibration step worth doing first.
The receiving device installs nothing
The phone runs the Bluetooth HID Device profile. That is the profile a real wireless keyboard uses. The host sees an ordinary keyboard and mouse. No driver, no background program, no account.
The first connection runs in five steps.
- Prepare both ends. Turn Bluetooth on, grant the permissions the app asks for, and open the host's Bluetooth screen.
- Pick the input profile. Windows US, Windows Korean 2-set, iOS US, or Android TV US.
- Start the connection. Make the phone discoverable, select it on the host, and confirm the pairing request on both sides.
- Wait for verification. The app sends a minimum report and checks that it lands.
- Calibrate the layout. Send the offered probe into an empty text field and say whether it matched.
Only a host that clears step 4 is saved under Connected devices and history. After that, reconnecting is picking it from that list.
Portrait hands you a trackpad and a keyboard at once
Rotate the phone and the whole layout changes. Portrait stacks a trackpad over a keyboard. Landscape gives the full screen to the keyboard, or to the trackpad, and you switch between them.
| Screen | What you get | How to switch |
|---|---|---|
| Portrait | Trackpad, both scroll axes, left and right click, and the keyboard together | No switching, they share the screen |
| Landscape keyboard | Full layout with Esc, F1-F12, Tab, Caps, Ctrl, Alt, and arrows |
Mouse at the lower right |
| Landscape trackpad | Wide trackpad plus PrtSc, Ins, Home, PgUp, Del, End, PgDn |
Keyboard at the lower right |
Drag anywhere on the pad to move the pointer. Tap once to left-click, twice to double-click. The vertical edge and the horizontal strip are separate scroll controls. That helps on wide tables and timelines. Horizontal scrolling depends on the application receiving it.
Compose on the phone when the sentence matters
Every key you press on the custom keyboard goes out immediately. That is what you want for shell commands and shortcuts. It is not what you want for a long sentence typed on a screen you are squinting at from the sofa.
Sentence input (system keyboard) solves that. You write with the phone keyboard you already use, read the line back, and send it when it is right. A space or Enter sends it, or you press Send. Host ⌫ sends a Backspace to the host, for fixing something already on the other screen.
The difference is where you correct typos. Immediate keys mean correcting on the host screen. Sentence input means correcting on the phone, before anything leaves it.
Calibrate once so both ends agree
The phone cannot read the host's keyboard layout. It can only assume one, which is what the input profile is. When the assumption is right, everything matches; when it drifts, the wrong characters arrive.
So the app asks instead of guessing. Focus an empty text field on the host and send the abc probe. Answer whether the result matched exactly. Do it again whenever the host's layout changes. If you also type Korean, set Keyboard language to Korean for the Korean/English key. The 가나다 probe checks that one.
Any host that accepts a standard Bluetooth keyboard is a candidate. Windows PCs, Macs, Linux boards like the Raspberry Pi, and other Android devices all qualify.
Wrap-up
A phone already carries the hardware a wireless keyboard needs. The receiving device installs nothing. Portrait keeps pointer and keys on one screen; landscape trades that for the full key layout. Send the probe once on a new host and you know the layout is right before it matters.
Try it on the machine that annoys you most. Open an empty text field, pair the phone, send abc, and see whether three letters come back.
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