User guide.

In normal mode

• Orange trigger — high-accuracy shots. The first press wakes the laser so you can aim; the second takes the shot.
• Up — short press: take a splay shot. Hold for ~1.5s: toggle Disco mode.
• Down — turn the laser off between shots to save battery. The trigger brings it back.
• Menu — open the settings menu.
• Power — press to turn the device on or off.

In menu mode, Up and Down scroll and either the orange trigger or Menu selects. The power button still turns the device off.

Hold at power-on

Holding a button while the device starts up gets you to the recovery routes:

• Down — boot straight into USB drive mode, even if the settings file is unreadable.
• Down + Menu — storage factory reset. You're asked to confirm; hold the trigger for 3s to erase. This wipes settings, calibration and any unsent shots, so it's the last resort.

The DiscoX has four buttons.

In normal mode

• Button 1 (Top) — take a measurement, or wake the laser if it's timed out.
• Button 2 — short press: take a measurement. Hold 2s: toggle Disco mode.
• Button 3 — open the settings menu.
• Button 4 (Bottom) — power on/off.

In menu mode, Buttons 1/2/3 become scroll-up, scroll-down, and select. Button 4 still powers the device off.

Once set up the DiscoX is a simple point-and-shoot device. The large orange button triggers high-accuracy shots: press it once to wake the laser and aim, then press again to shoot. The device checks it is being held steady (LED turns red) before taking the shot (LED turns green) — so hold it still until the shot lands.

To save battery, and to show you the shot worked, the laser turns off after every high-accuracy shot. The next press of the trigger turns it back on for aiming.

LED states

Splay shots

The up button takes splay shots. These skip the stability check, so they are not as precise as shots taken with the orange button, but they are much faster to take — and the laser stays on afterwards so you can fire off the next one straight away.

Splays don't count towards station detection, so a run of splays between stations never interferes with your legs.

Turning the laser off

To turn the laser off between shots press the down button. It only ever turns the beam off — a stray press underground can cost you a re-press, but it will never light the laser unasked. The orange trigger brings it back. The laser also switches itself off after the laser timeout (2 minutes by default).

Stations

If 3 shots are taken at the same target 3 times in a row, the device registers this as a station: it flashes white, plays a rising fanfare, blinks the laser, and then lights up purple. Shots count as the same target when their end points fall within the leg tolerance of each other (10 cm by default — Menu → Settings → Leg tol).

The display stays frozen on the reading until you take the next shot.

Sounds

The buzzer has a different sound for each event, so you can survey without looking at the device:

• Click — shot started.
• Bleep — reading taken and saved.
• Rising fanfare — station recognised.
• Falling womp — something went wrong, check the screen.

Press Button 1 or Button 2 (short press) to take a reading. The device waits until the sensors have settled before accepting a shot — hold the device still during readings.

LED states

After a shot the display freezes on the recorded reading and the laser turns off. Press any measure button to re-enable the laser, then press again to take the next reading.

Leg detection

When three consecutive shots agree in bearing, clino, and distance (within configurable tolerances), the DiscoX recognises a complete survey leg. The LED pulses purple, the laser flashes briefly, and the buzzer beeps three times. The display stays frozen on the leg data until you press a measure button to continue.

Laser wake

If the laser has auto-timed-out, pressing any measure button re-enables it with a short beep before taking the shot.

Hold the up button for about 1.5 seconds to toggle disco/rave mode. The laser shuts off and the LED cycles through colours. Shake the device for faster colour cycling and full brightness.

To get back to surveying, press the orange trigger — or hold the up button again to switch disco off where it stands.

Hold Button 2 for 2 seconds to toggle disco/rave mode. The laser shuts off and the NeoPixel cycles through colours. Shake the device for faster colour cycling and full brightness.

To exit press any of the buttons other than the power button. The laser restarts and the device returns to normal operation.

Plug the DiscoX into your computer first, then go to Menu → Update Firmware → Yes. The device enters the UF2 bootloader and appears as a removable drive. Drag and drop the new .uf2 file onto it — the DiscoX reboots when flashing is complete. Your settings, calibration and any unsent shots survive the update.

The device has to be connected before you pick Yes: the bootloader only waits a few seconds for the USB connection before dropping back into the normal firmware.

Go to Menu → Update / Settings → Update Firmware. The device enters the UF2 bootloader and appears as a removable drive. Drag and drop the new .uf2 file onto it — the DiscoX reboots when flashing is complete.

All common settings are accessible from the onboard menu — press Menu to open it, Up/Down to scroll, and the orange trigger or Menu to select.

Onboard menu

• Exit — back to surveying.
• Enter Calibration — run Part 1 (Ellipsoid) or Part 2 (Alignment), perform a Mag Field Check, or view the last results.
• Measure from: — measure from the back of the device (its length is added on) or the front (raw laser distance).
• Settings — the submenu below.
• Play Snake — hidden bonus for when you're waiting around.
• Update Firmware — reboot into the bootloader to flash a new .uf2.
• Delete saved shots — wipe any pending readings stored in flash.

Settings submenu

• Laser off — 30s · 60s · 2m · 5m · 15m · 30m of inactivity before the laser shuts down.
• Anomaly Detec — toggle warnings for nearby metallic objects (helmet lights, SRT kit, bolts).
• Shutdown — 5 · 10 · 15 · 30 · 60 min · 2 hr auto power-off.
• Brightness — screen contrast, 1% to 100%.
• Leg tol — how close three shots must land to count as a station, 4 cm to 30 cm.
• USB Drive Mode — mount the device on a computer to edit its settings and calibration files.
• Reformat Storage — erase and rebuild the device's filesystem. Only needed if storage is corrupt.

Advanced: config.json

Go to Menu → Settings → USB Drive Mode. The DiscoX reboots and appears as a drive called MRZAPPY holding CONFIG.JSON, CALIBRATION.JSON, READINGS.CSV (your unsent shots, export only) and a README.TXT. Edit the values you want, save, eject the drive on your computer, then press Menu on the device to import and restart. Any setting you omit uses its default, and a file that doesn't parse is rejected — the device keeps the old one rather than starting up misconfigured.

If the device ever won't boot far enough to reach the menu, hold Down while turning it on to get to the same drive.

Measurement & stability

stability_tolerancedefault 0.5	Degrees the sensors must converge within before a high-accuracy shot is accepted. Lower = stricter.
stability_buffer_lengthdefault 5	Consecutive stable samples required before accepting a reading.
ema_alpha_stabledefault 0.15	Smoothing applied while the device is held still. Lower = smoother but slower-reacting.
ema_alpha_movingdefault 0.6	Smoothing applied while the device is moving, so the display keeps up as you swing onto a target.
laser_distance_offsetdefault 0.12	Device length in metres, added to the laser distance when measuring from the back so readings are station-to-station.
measure_from_frontdefault false	true uses the raw laser distance instead (same as Menu → Measure from).
splays_enableddefault true	Whether a short press of the up button takes a splay shot.

Station detection

cartesian_tolerancedefault 10.0	Centimetres. Three shots count as the same station when their end points all fall this close together — one number covering bearing, clino and distance at once. Same as Menu → Settings → Leg tol.
laser_wibbledefault true	Blink the laser on/off in quick succession when a station is detected.
leg_angle_tolerancedefault 1.7	Degrees. Used by the Mag Field Check to decide that a foresight and backsight are a matching pair.

Laser shot validation

laser_shotsdefault 1	Shots taken per measurement. Above 1 the median of the surviving shots is used — slower, but steadier on awkward targets.
laser_sq_limitdefault 50	Minimum signal quality for a shot to be trusted. Raise it to reject more dark/shiny targets, set to 0 to accept everything.
laser_spread_limit_mmdefault 25	How far apart multiple shots may land and still be averaged. Only relevant when laser_shots is above 1.

Anomaly detection

anomaly_detectiondefault false	Enable warnings when nearby metallic objects may be distorting the magnetic field. Turn this on once the device has been calibrated in your own environment.
mag_tolerancedefault 10.0	Magnetometer field-strength tolerance in degrees from the expected local field.
grav_tolerancedefault 10.0	Accelerometer magnitude tolerance in degrees.
dip_tolerancedefault 10.0	Magnetic dip-angle tolerance in degrees.

Calibration

cal_mag_consistencydefault 0.5	Angular consistency window in degrees for the magnetometer during calibration.
cal_grav_consistencydefault 0.4	Angular consistency window in degrees for the accelerometer during calibration.
cal_buffer_lengthdefault 5	Samples in the calibration consistency window.
cal_settle_msdefault 250	Milliseconds the device must remain stable before a cal point is accepted.
cal_ema_alphadefault 0.3	EMA smoothing used during calibration.
cal_timeout_msdefault 4000	Max ms to wait for stability before a cal point is force-accepted.

Timers & display

auto_shutdown_timeoutdefault 1800	Seconds of inactivity before automatic power-off (1800 = 30 min).
laser_timeoutdefault 120	Seconds of inactivity before the laser turns off to save power.
screen_brightnessdefault 255	OLED contrast level, 0–255.

Bluetooth

ble_namedefault "SAP6_DiscoX"

Bluetooth device name advertised to survey apps. Max 20 characters; the SAP6_ prefix is added for you if you leave it out.

All common settings are accessible from the onboard menu — press Button 3 to open it.

Onboard menu

• Enter Calibration — run a calibration, perform a Mag Field Check, or view last results.
• Anomaly Detection — toggle warnings for nearby metallic objects (helmet lights, SRT kit, bolts).
• Laser Timeout — 30s · 60s · 2m · 5m · 15m · 30m.
• Auto Shutdown — 5 · 10 · 15 · 30 · 60 min · 2h.
• Delete Saved Shots — wipe any pending readings stored in flash.
• Measure From: — lets you choose whether to measure from the front or back of the device.
• Update / Settings — firmware update and advanced config.
• Play Snake — hidden bonus for when you're waiting around.

Advanced: config.json

Go to Menu → Update / Settings → Edit Settings File. The DiscoX reboots into USB drive mode and appears as a drive called DISCOX. Open config.json, edit values, save, eject, then hold the power button to restart. Any setting you omit uses its default.

Measurement & stability

stability_tolerancedefault 0.4	Degrees the sensors must converge within before a shot is accepted. Lower = stricter.
stability_buffer_lengthdefault 3	Consecutive stable samples required before accepting a reading.
ema_alphadefault 0.3	Exponential moving average smoothing. Lower = smoother but slower-reacting.
laser_distance_offsetdefault 0.162	Device length in metres, subtracted from raw laser distance so readings are station-to-station.

Leg detection

leg_angle_tolerancedefault 1.7	Max difference in degrees between three consecutive shots' bearing/clino to count as the same leg.
leg_distance_tolerancedefault 0.05	Max difference in metres between three distance readings for leg detection.
laser_wibbledefault true	Blink the laser on/off in quick succession when a leg is detected.

Anomaly detection

anomaly_detectiondefault false	Enable warnings when nearby metallic objects may be distorting the magnetic field.
mag_tolerancedefault 10.0	Magnetometer field-strength tolerance in degrees from expected local field.
grav_tolerancedefault 10.0	Accelerometer magnitude tolerance in degrees.
dip_tolerancedefault 10.0	Magnetic dip-angle tolerance in degrees.

Calibration

cal_mag_consistencydefault 0.5	Angular consistency window in degrees for the magnetometer during calibration.
cal_grav_consistencydefault 0.4	Angular consistency window in degrees for the accelerometer during calibration.
cal_buffer_lengthdefault 5	Samples in the calibration consistency window.
cal_settle_msdefault 250	Milliseconds the device must remain stable before a cal point is accepted.
cal_ema_alphadefault 0.3	EMA smoothing used during calibration.
cal_timeout_msdefault 3000	Max ms to wait for stability before a cal point is force-accepted.

Timers & display

auto_shutdown_timeoutdefault 1800	Seconds of inactivity before automatic power-off (1800 = 30 min).
laser_timeoutdefault 120	Seconds of inactivity before the laser turns off to save power.
screen_brightnessdefault 255	OLED contrast level, 0–255.

Bluetooth

ble_namedefault "SAP6_Unicorn"

Bluetooth device name advertised to survey apps. Max 20 characters.