Can we scale the CPU down to 10 MHz? How to do that dynamically? How much current is drawn from the battery?

Add a LED, blink on successful operation (punching, configuration etc). A distinctive signal should be produced for failure.

Need to configure station parameters in a web interface, like LUCI in OpenWrt.

There's a menu item, but not backed with functionality. Implement it.

• Cycle operation modes - normal, BT, WiFi
• Connect to a WiFi AP
• Create a TCP server on port 23
• Route recv, send to the shell
• Configure WiFi ssid and password
• Consider creating an AP too

Store/restore clock offsets

Add some persistency to the edit text fields, like it's done with the encryption key.

Make navigation panel behave more idiomatic:

• sandwich button to show/hide navigation panel
• autohide navigation panel when clicked outside of it

Add to github actions

Update for the alternative MCU.

serialEvent() doesn't work. Instead, I have to poll the serial for input for now.

Add explanation and verbal instructions to every view.

It'll have to be run on a couple of devices simultaneously.

Update firmware via BLE.

Hide it from the view, require authentication to reveal and edit

The record of punched cards should be cleared automatically after 1 day, for example. This would allow reusing stations for different competitions without CLI.

The library selects a random card. If there's more than one, all should be punched.
Confirmation signals should indicate how many cards are punched in unary code, for example: da, da-da, da-da-da

Implement distinct notification of card overflow. This is important for service cards.

Before an event, every station must be configured to set:

• encryption key
• station id
  The clock must be either synchronized or calibrated. The readout station/app should know the time base of every station.

A card should be issued:

• formatted
• with ID assigned and registered
• ready to be read out

QR scanning from qr-o-punch? A separate plugin for QE?

How to determine git rev?

Use a bit mask of configurable length. Choose consecutive intervals to spread wear. CLI commands. Unit tests.

Add piezo buzzer to produce positibe/negative confirmation when punching, configuring etc.

In the Ukrainian language first.

CLI will be used for configuration and operation.

Instead of recompiling and reflashing the set of stations, make the timeout configurable. What's the best default value, 3 hours?

Investigate and implement wireless configuration of stations. Use a special service card for wireless activation.

Allow changing with passwd

Standalone stations could serve as either punchers or cleaners at the start line. One way to repurpose the hardware is to build and use a different program. Another way could be a runtime configuration. Devise a way to:

• configure a station in runtime
• show distinctive indication

• Configure SQW to output 1kHz
• Connect to Pin2
• Handle INT0 to increment counter 0..1024
• Align the counter with the second boundary
• Set the offset during synchronization
• Take the counter reading when punching to round to the closest second.

Can use QR-O-Punch format for that.

Use https://github.com/Jakeler/ble-serial to scan devices around and configure them all at once.

Probably, could be done with ordinary exception and proper exception display.