Documentation · v1
Everything you need to operate your DiscoX. Written for the latest C++ firmware — bookmark this page and it'll stay current.
The DiscoX has four buttons across the top of the device — all operable with gloved hands.
In menu mode, Buttons 1/2/3 become scroll-up, scroll-down, and select. Button 4 still powers the device off.
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.
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.
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.
If the laser has auto-timed-out, pressing any measure button re-enables it with a short beep before taking the shot.
The 128×128 pixel OLED shows three values from your most recent stable shot:
The top-left shows BT when Bluetooth is connected, with a count of pending (unsent) readings beside it. The top-right shows a proportional battery bar — no guessing when you're underground.
Hold Button 2 for 2 seconds to toggle disco/rave mode. The laser shuts off and the NeoPixel cycles through colours. Shake the device to kick into wild mode — faster cycling, full brightness.
Hold Button 2 again for 2 seconds to exit. The laser restarts and the device returns to normal operation.
The DiscoX works with current versions of SexyTopo and TopoDroid via a long-range C++ implementation of the SAP6 BLE protocol. The device advertises continuously, so nearby phones and tablets will discover it automatically.
Once connected, the device flashes blue, a BT label appears in the top-left of the screen, and live readings are pushed directly to your survey app.
Each DiscoX ships with a unique Bluetooth name in the format SAP6_[Nickname] — for example SAP6_Dragon. Change it via the settings file (see below), or request a specific name before assembly.
All common settings are accessible from the onboard menu — press Button 3 to open it.
config.jsonGo 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.
| 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_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_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. |
| 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. |
| 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. |
| ble_namedefault "SAP6_Unicorn" | Bluetooth device name advertised to survey apps. Max 20 characters. |
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.
Calibrate whenever you survey in a new area or if readings seem off. Run a Mag Field Check before each trip to quickly verify accuracy at your survey site.
To start: press Button 3 → Enter Calibration → choose a type.
The most accurate option. Runs in two phases automatically.
Phase 1 — Ellipsoid (56): aim in a wide variety of directions. Spread points evenly across the sphere — like touching every zone of a globe's surface. A coverage bar shows progress.
Phase 2 — Alignment (24): 3 sets of 8 readings. Each set aims at one fixed point; barrel-roll ~45° between shots. Pick 3 fixed points roughly 90° apart. Three beeps = next direction.
Faster option for quick field recalibration.
Take 3 sets of 8 readings. For each set, barrel-roll the laser around a single fixed point, rotating ~45° between shots. The 3 points should be roughly 90° apart — e.g. ahead, right, vertically up.
The same 24 readings fit both ellipsoid and alignment, so this is quicker but less thorough than the long version.
Verifies calibration accuracy without re-running a full cal.
Shoot a fixed target, walk to it, shoot back. Repeat for 3+ pairs in different directions. The device records each pair's bearing error and calculates an overall correction amplitude.
A consistently high amplitude means it's time for a full long calibration.
After calibration the screen shows three quality scores. Lower is better in all cases. View them any time via Menu → Enter Calibration → View Last Cal.
For best results, calibrate in the same magnetic environment as your survey — i.e. away from bolts, helmet lights, and SRT kit. Anomaly detection will warn you if your calibration is being contaminated.