Display & Menu
The UPS has a 64 × 32 monochrome OLED and two red buttons, one on each side of the display. On power-up it plays a short melody and shows a splash screen for a few seconds while readings stabilize, then lands on the Home screen.
Status Screens
The Home screen is the main display: a battery icon (fill = charge level, animates while charging), charge %, mode label, battery voltage, plus input and output voltage.
Mode labels: DSC discharging (on battery) · PRE pre-charge · CHG charging · FUL full · IDL on external power, not charging.
Debug Screens
Not in the production release
Current firmware additionally has four debug screens. They will be removed from the production firmware.
Cycled with short button presses; a small position strip in the bottom-right corner shows where you are, and the display returns to Home automatically after 20 s without a button press.
| Screen | Shows |
|---|---|
| INPUT | Input voltage, negotiated USB-C PD contract and its wattage, active source (USB-C / barrel / off) |
| OUTPUT | Measured output voltage, the PD contract offered to the Pi, current limit |
| BATTERY | Battery voltage and charge %, mode label, charge current |
| SYSTEM | Uptime, board and charger temperatures, fault code |
BAD PSU screen
If the input supply is present but out of range, the display switches to a flashing BAD PSU warning (with alarm beeps) until you connect an adequate charger. This overrides all other screens.
Buttons
| Context | LEFT | RIGHT |
|---|---|---|
| Home / debug screens | Short press: previous debug screen. Hold 2 s on Home: open the menu | Short press: next debug screen |
| Menu | Move cursor down (wraps) / toggle the highlighted option | Select / activate |
| Confirmation prompts (device claiming) | Hold both buttons for the on-screen countdown to confirm; release to abort |
Every press gives a short click from the buzzer (unless sound is off).
Local Menu
Hold LEFT for 2 s on the Home screen. Navigate with LEFT (down) and RIGHT (select); the menu closes itself after 60 s of inactivity, saving any pending change.
| Entry | What it does |
|---|---|
| Bright | Display brightness, 6 levels with live preview — RIGHT cycles, LEFT saves and returns |
| Sound | Toggles the buzzer ON/OFF with RIGHT, saved immediately |
| Info | Read-only: uptime and board/charger temperatures; any button returns |
| Output | Shows the output state; Turn OFF asks for confirmation (CUT PWR TO PI?) before cutting power to the Pi, Turn ON is immediate |
| Network | Opens the connectivity menu of the optional LTE-M module — backend mode selection, HTTP key, device wallet, and factory reset (Reset). See Connectivity. Without the module fitted it shows a brief NO MODEM notice |
| Exit | Closes the menu |
Bright and Sound persist across power cycles and battery swaps. A factory reset (in the Network menu) restores both to defaults.
Sound OFF mutes everything
Turning Sound off silences all audio, including the power-loss and low-battery alarms — not just button clicks.