The Tastkiesel build log

Typing on a smart TV is miserable: search terms, account names and Wi-Fi passwords are entered letter by letter with a D-pad on an on-screen keyboard. The workarounds — a full keyboard on the sofa, a phone remote app, voice search — each give up something: the couch, your eyes on the screen, or the ability to type a password at all.

On a Nokia, typing was blind, one-handed and fast: nine keys, three taps per letter at most, and the phone suggested the word. No TV offers that today. Tastkiesel exists to find out, in public, whether enough people miss it — and to build the keypad only if they do.

The honest inventory: this site, with a working sample of how T9 suggestions feel in a browser (try typing 6-3-8-3-5-4-9 — it is a demo, not the device), a price band that says plainly there is nothing to buy, and a double-opt-in waitlist aimed at 500 confirmed signups. Every claim on the home page is labelled unproven until it has been measured on real hardware, and the status board G1–G7 tracks which founder checks are still open.

The gadget itself — a small T9 keypad with its own display and its own 2.4 GHz radio talking to a USB-C dongle in an Android phone — is a sketch with a hardware budget of at most €500. Nothing has been bought, soldered or flashed.

The next build-log entries are desk research, written up as open technical requirements, never as finished features: whether ESP-NOW or a dedicated 2.4 GHz module is the right radio, how USB host mode behaves on Android, which Qi coil fits a pocket device, an honest energy model, and a first bill of materials.

If you have ESP32 or radio experience and want to argue with the numbers, that is exactly what the log is for — reply to any newsletter from the waitlist, and we will quote what we got wrong.

The first desk-research question from the last entry is done on paper: which radio carries the keystrokes from keypad to dongle. Nothing is decided until it is measured, but the numbers now exist to argue with.

ESP-NOW, Espressif’s connectionless radio protocol, looks tempting: in Espressif’s own outdoor benchmark it stayed under 20 milliseconds to 300 metres. But ESP-NOW only speaks between Espressif chips, so the USB-C dongle in the phone would need to be an ESP32 too. The Wi-Fi radio in an ESP32 also draws roughly 160 to 260 milliamps while transmitting. A dedicated module like the nRF24L01+ needs about 11 mA, roughly a tenth of that.

Commercial wireless keyboards already made this choice: the Logitech Unifying dongle is an nRF24-class radio acting as a plain USB keyboard. Android phones act as USB hosts, so such a dongle should work over USB-C without drivers. That is a claim to test per phone, not to trust.

So the open requirement leans toward a dedicated low-power radio for the keypad. An ESP32 remains a possible bridge on the dongle side. All of it stays desk research: nothing is bought, and the checks G1–G7 remain unproven on hardware. If you have built either radio into a pocket device, the build-with-us call below wants your numbers.

The radio entry ended on a claim to test per phone: that a plain HID dongle works over USB-C. That claim is now desk research too, and it mostly holds, with three real catches.

Android has recognised USB keyboards natively since version 3.1, and the official documentation names keyboards and mice as its first examples. No app, no root and no driver are needed: the phone just sees someone typing. But the same documentation warns that host support is optional per device, so every phone model stays its own test.

The soft keyboard is the first catch. When a hardware keyboard attaches, Android suppresses it by default through a system setting. Letters still appear in the field, but the phone’s word suggestions disappear with it. So the T9 word prediction cannot come from the phone: it has to live on the keypad or dongle chip entirely.

Power is the second catch, and it is small. The phone powers the dongle as host. The OTG standard demands at least 8 mA of that supply, and phone ports typically allow about 500 mA. A keypad dongle needs single-digit milliamps, so power is a non-issue.

The third catch is a vendor quirk. Several makers, including Xiaomi and the OnePlus family, hide OTG behind a settings toggle that switches itself off after 10 idle minutes. A dongle there must expect the connection to vanish mid-evening and survive being re-enumerated.

The plain-HID path therefore survives on paper. Real products like card readers and barcode scanners already type into phones as HID keyboards. That turns the next open requirement into a per-phone matrix of which models expose host mode and which hide it. The checks G1–G7 stay unproven on hardware, and nothing has been bought.