Calibration

HelixScreen provides built-in tools for the most common Klipper calibration tasks.

Looking for touchscreen calibration? See the Touch Calibration Guide.

Bed Mesh

Bed Mesh Panel

3D visualization of your bed surface:

Color gradient: Blue (low) to Red (high)
Touch to rotate the 3D view
Mesh profile selector: Switch between saved meshes

Actions:

Button	What It Does
Calibrate	Run new mesh probing
Clear	Remove current mesh from memory
Load	Load a saved mesh profile

The visualization mode (3D, 2D, or Auto) can be changed in Settings > Display.

Screws Tilt Adjust

Screws Tilt Panel

Assisted manual bed leveling:

Navigate to Advanced > Screws Tilt
Tap Measure to probe all bed screw positions
View adjustment amounts (e.g., “CW 00:15” = clockwise 15 minutes)
Adjust screws and re-measure until level

Color coding:

Green: Level (within tolerance)
Yellow: Minor adjustment needed
Red: Significant adjustment needed

Input Shaper

Input Shaper Panel

Tune vibration compensation for smoother, faster prints:

Navigate to Advanced > Input Shaper
Review your current shaper configuration displayed at the top
Pre-flight check verifies accelerometer is connected
Select axis to test (X or Y)
Tap Calibrate to run the resonance test (5-minute timeout applies)
View frequency response chart with interactive shaper overlay toggles
Review the comparison table showing recommended shaper and alternatives (frequency, vibration reduction, smoothing)
Tap Apply to use for this session or Save Config to persist

Chart features:

Toggle different shaper types on/off to compare their frequency response curves
Platform-adaptive: full interactive charts on desktop, simplified on embedded hardware
Per-axis results shown independently

Input Shaper Results

Requirement: Accelerometer must be configured in Klipper for measurements. If no accelerometer is detected, the pre-flight check will show a warning.

Probe Management

View and control your Z probe from Advanced > Probe Management. HelixScreen auto-detects your probe type and shows the appropriate controls.

Supported probe types:

Probe	Detected As	Type-Specific Controls
Cartographer	Cartographer	Calibrate, Touch Cal, Scan Cal
Beacon	Beacon	Calibrate, Auto-Calibrate
BTT Eddy / Mellow Fly Eddy	Eddy Current	Calibrate, Drive Current Cal
BLTouch	BLTouch	Deploy, Stow, Reset, Self-Test
Voron Tap	Voron Tap	—
Klicky	Klicky	Deploy, Dock
Standard probe	Probe	—

Universal actions (all probe types):

Button	What It Does
Accuracy Test	Runs `PROBE_ACCURACY` to check probe repeatability
Z-Offset Cal	Opens the interactive Z-offset calibration panel
Bed Mesh	Opens the bed mesh calibration panel

Configuration: Tap any config row (X/Y offset, samples, speed, retract distance, tolerance) to edit probe settings directly — changes are saved to your Klipper config with a firmware restart.

Z-Offset Calibration

Z-Offset Panel

Interactive panel for dialing in your Z-offset when not printing. Works with all probe types — Cartographer, Beacon, BLTouch, eddy current probes, and standard probes.

Navigate to Advanced > Z-Offset, or tap Z-Offset Cal in the Probe Management overlay
Optionally enable Warm Bed to heat the bed before calibrating (accounts for thermal expansion)
Tap Start — the printer homes and begins the calibration sequence
Use the +/− adjustment buttons to lower the nozzle (paper test: adjust until paper drags slightly)
Tap Accept when satisfied, or Abort to cancel
The offset is saved to your Klipper config automatically

HelixScreen picks the right calibration command for your setup (PROBE_CALIBRATE, Z_ENDSTOP_CALIBRATE, or SET_GCODE_OFFSET) based on your printer’s detected probe configuration.

Quick access: A Z Calibration button is also available on the Controls panel for one-tap access.

Belt Tension (Beta)

Uneven belt tension is one of the most common causes of print quality issues on CoreXY and Cartesian printers. Loose or mismatched belts produce visible artifacts like layer shifts, vertical fine artifacts (VFAs), and ringing/ghosting. HelixScreen’s Belt Tension tool measures the resonant frequency of each belt path and compares them, giving you a clear picture of your belt tension balance.

How It Works

Every belt has a natural resonant frequency determined by its length, mass, and tension — just like a guitar string. Tighter belts vibrate at higher frequencies. On a CoreXY printer, the two diagonal belt paths (Path A and Path B) should have very similar frequencies, meaning their tension is balanced.

The Belt Tension tool:

Vibrates each belt path using TEST_RESONANCES
Records the vibration with your accelerometer
Computes a frequency spectrum (PSD) to find the peak resonant frequency
Compares the two paths and provides a recommendation

Requirements

Accelerometer (ADXL345, LIS2DW, or MPU) configured in your Klipper printer.cfg
CoreXY or Cartesian kinematics (auto-detected)
Optional: A [pwm_cycle_time] LED pin for stroboscopic fine-tuning

No accelerometer? The strobe fine-tuning mode can still be used to visually identify belt resonance using a phone strobe app — no accelerometer needed for that step.

Running a Belt Tension Check

Navigate to Advanced > Belt Tension (requires beta features enabled)
Review the hardware summary card showing your detected kinematics, accelerometer status, strobe LED availability, and target frequency
Tap Start Check
The printer homes (if needed), then runs a resonance sweep on each belt path
A progress bar shows the measurement status (“Measuring Path A… / Path B…”)

Reading the Results

When the measurement completes, the results screen shows:

Path A and Path B cards:

Measured frequency in Hz
Status indicator: Good, Needs adjustment, or Out of range

Comparison section:

Frequency Delta — the difference between Path A and B in Hz. Ideally under 5 Hz; over 15 Hz means adjustment is needed
Path Similarity — how closely the vibration profiles match (Pearson correlation). Above 90% is excellent; below 70% suggests uneven tension

Recommendation card:

A specific, actionable message like “Tighten Path A belt to match Path B” or “Belt tension looks good!”

Status thresholds:

Status	Condition
Good (green)	Within target frequency range
Needs adjustment (orange)	Moderately off target
Out of range (red)	Far from target, or large A/B imbalance

Interpreting Frequencies

Target frequency defaults to 110 Hz, which is typical for Voron-style CoreXY printers. Different printer designs may have different ideal frequencies — check your printer’s documentation.

Frequency	Meaning
Both paths match, near target	Belt tension is balanced and correct
Both paths match, but low	Belts are balanced but too loose — tighten both equally
Both paths match, but high	Belts are balanced but overtightened — loosen both equally
Paths differ significantly	Tension is unbalanced — tighten the lower-frequency belt

Strobe Fine-Tuning Mode

After getting initial results, tap Visual Fine-Tune (Strobe) for precise belt tension matching. This mode vibrates the belt at a specific frequency while a strobe light flashes in sync — when the belt appears to “freeze” (stand still), you’ve found the resonant frequency.

With a PWM strobe LED:

If your printer has a [pwm_cycle_time] LED configured in Klipper, HelixScreen automatically syncs the LED strobe to the motor excitation frequency. Watch the belt under the strobe and adjust frequency with the +0.5 Hz / -0.5 Hz buttons until the belt appears stationary.

Klipper configuration for strobe LED:

[pwm_cycle_time strobe_led]
pin: <your_gpio_pin>    # Any available GPIO connected to an LED
value: 0                 # Start off
cycle_time: 0.01         # Default (will be changed dynamically)

Without a strobe LED (phone app fallback):

HelixScreen shows the current frequency and recommends phone strobe apps you can use:

Android: Strobily, Strobe Light
iOS: Strobe Light Tachometer, myStroboscope

Set the app to the displayed frequency, aim your phone at the belt, and adjust until the belt appears frozen.

Locking frequencies:

Use the Lock A and Lock B buttons to record the resonant frequency you found for each path.

Tips

Run the check after any belt adjustment to verify your changes had the desired effect
Tap “Test Again” on the results screen to re-run without leaving the panel
Path A corresponds to the 1,1 diagonal on CoreXY printers (both motors moving the same direction). Path B is the 1,-1 diagonal (motors moving opposite directions). Check your printer’s documentation for which tensioner adjusts which path
Temperature matters — belt tension can change slightly with temperature. Run the check at your typical operating temperature for the most accurate results
The frequency chart (coming soon) will show the full frequency response curves for both paths, making it easier to spot issues like secondary peaks or broad resonance

Heater Calibration (PID / MPC)

Heater Calibration Panel

Calibrate temperature controllers for stable heating. HelixScreen supports two calibration methods:

PID — Classic proportional-integral-derivative tuning. Works on all Klipper firmware.
MPC (Beta) — Model Predictive Control. A physics-based thermal model that can provide more stable temperatures. Requires Kalico firmware (a Klipper fork with MPC support).

PID Calibration

Navigate to Advanced > Heater Calibration
Select Nozzle or Bed
Choose a material preset (PLA, PETG, ABS, etc.) or enter a custom target temperature
Optionally set fan speed — calibrating with the fan on gives more accurate results for printing conditions
Tap Start to begin automatic tuning

During calibration:

Live temperature graph shows the heater cycling in real-time
Progress percentage updates as calibration proceeds
Abort button available if you need to stop early
A 15-minute timeout acts as a safety net for stuck calibrations

When complete:

View new PID values (Kp, Ki, Kd) with old-to-new deltas so you can see what changed
Tap Save Config to persist the new values to your Klipper configuration

Tip: Run PID tuning after any hardware change (new heater, thermistor, or hotend) and with the fan speed you typically use while printing.

MPC Calibration (Beta — Kalico Only)

If you are running Kalico firmware and have beta features enabled, a Method selector appears with MPC and PID options. HelixScreen auto-detects Kalico — the selector only appears when it is detected.

Navigate to Advanced > Heater Calibration
Select MPC in the Method selector (marked with a BETA badge)
Select Nozzle or Bed
Choose a target temperature preset
For nozzle calibration, select a fan calibration level: Quick (3 points), Detailed (5 points), or Thorough (7 points) — more points improve accuracy but take longer
If switching from PID to MPC for the first time, enter your heater wattage (check your heater’s rating — typically 40–60W for hotends)
Tap Start

First-time MPC switch: If your heater is currently configured for PID, HelixScreen will automatically update your Klipper configuration to MPC mode and restart Klipper before beginning calibration. A progress screen shows “Updating Configuration…” during this step.