OLED Display Output

Display behaviour

Three settings on the Display config page control when the OLED is on:

• Timeout (push-button builds only) - seconds of inactivity before the display turns off after a tap. 0 falls back to the On/Off Time schedule below.
• On Time / Off Time - daily schedule; outside the window the display is off. Leave both blank for “always on”. Window crosses midnight if from > to (e.g. 22:00–07:00).
• Brightness - 0–100 %.

On builds without a push button, only the schedule applies.

On builds with a push button, the resolution order is:

1. Long-press override active → display always on.
2. Otherwise, if Timeout > 0 → on for Timeout seconds after each tap.
3. Otherwise (Timeout = 0) → follow On/Off Time schedule, with a 30-second wake window after any tap so you can check readings during off-hours.

Push-button operations

Single press

Cycles through the information pages. If the display is off, the first tap turns it on and shows page 1.

Long press

Toggles the always-on override. The onboard LED flashes once when the override turns on (display will follow Timeout/schedule normally), twice when it turns off (display stays on permanently). On ESPGeiger-HW devices the beeper reacts in time with the LED.

Pin configuration

Builds without OLED_PINS_BLOCKED expose the OLED I2C pins as runtime prefs (I2C SDA Pin and I2C SCL Pin) on the same Display config page. Changes trigger a reboot to take effect. Purpose-built kits set OLED_PINS_BLOCKED at compile time so the pins stay fixed.

Browser screen viewer

OLED builds expose a live preview of the framebuffer at /screen. The page redraws ~5 times a second from a raw fetch of the 1024-byte framebuffer, picks a phosphor tint, and accepts virtual button taps - useful for headless debugging, remote demos, or screenshots without a phone camera. The view is rendered even on builds compiled with display support but no display attached, so you can build a UDP-receiver build with esp8266oled_udp and still see what the panel would show.

Path	Returns	Use
/screen	HTML viewer page	Interactive view in the browser
/screen.bin	Raw 1024-byte framebuffer	Direct decode (column-packed, 128x64 1bpp)
/screen.bmp	Transposed PNG-alike	One-shot screenshot
/screen/tap	OK	Virtual short press of the user button (push-button builds)

The viewer remembers your phosphor tint choice in localStorage. The /screen.bin endpoint is what you want if you’re scripting against the device.