Ergo Desk Calibrator

Overview

Almost every home desk is wrong in the same direction: the desk is too high for the person (75 cm "standard" suits ~185 cm people — everyone shorter hunches shoulders), the monitor sits 10-20 cm below eye line (neck flexion), and the laptop is used flat on the desk (worst of all worlds). The result shows up as the 3 PM neck ache, wrist tingles, and eye fatigue that people blame on "too much computer" when it's a geometry problem with exact numbers.

This skill computes YOUR numbers from your height using standard anthropometric proportions, then checks your setup against them:

1. calibrate — height → seat height, desk height, monitor top-edge height above floor AND above desk, viewing distance, lumbar support point, keyboard slope. Standing-desk variant included.
2. monitor — any screen size: does its top edge land at/below your eye line on your desk? Riser cm needed.
3. laptop — the laptop compromise protocol (laptop screen + built-in keyboard is unsolvable; riser + external keyboard is).
4. symptom — pain → ranked likely causes → exact fixes.
5. checklist — 12-point posture self-audit + 20-20-20 eye rule schedule.

Pure stdlib, offline. Guidance reflects widely published ergonomic practice (OSHA computer-workstation concepts); not medical advice — persistent pain deserves a clinician.

When to Use

• New desk / chair / monitor, or building a WFH corner
• "What height should my standing desk be?"
• Neck/shoulder/wrist/eye strain after work sessions
• Buying decisions: will a 27" monitor be too tall/close for my setup?
• Periodic re-check after moving furniture

Don't use for: clinical rehabilitation, existing RSI diagnosis treatment (see a professional), or industrial/manual-handling ergonomics (different domain).

The Math (why these numbers)

Proportions of stature H (population-average, seated erect):

Consequences worth knowing:

• A 75 cm fixed desk forces shoulder shrugging on everyone under ~181 cm.
• Eyes sit ~0.26 H above the desk surface → a 24" monitor's top edge on its lowest stand lands close to eye line; bigger monitors need LOWERING or more distance, not risers.
• Monitor top edge AT or slightly BELOW eye line; screen center 10-15 cm below eyes; never top edge above eye line.

How It Works — Numbered Steps

1. Get your numbers:

   python3 scripts/ergo_setup.py calibrate --height 175
   python3 scripts/ergo_setup.py calibrate --height 163 --standing
   

2. Check a monitor against your setup:

   python3 scripts/ergo_setup.py monitor --height 175 --size 27
   

   → prints top-edge height above desk on a typical stand and the cm of riser/lowering needed to hit eye line.
3. If you work on a laptop:

   python3 scripts/ergo_setup.py laptop --height 175
   

4. Diagnose from symptoms:

   python3 scripts/ergo_setup.py symptom --pain neck
   python3 scripts/ergo_setup.py symptom --pain wrist
   

5. Audit yourself weekly:

   python3 scripts/ergo_setup.py checklist
   

Common Pitfalls

1. Desk too high is the #1 home-office error. Fix by raising the chair to elbow height and adding a footrest — not by lowering the chair and shrugging.
2. Monitor directly on laptop-stand height for the built-in keyboard. When you raise the screen to eye level, the built-in keyboard becomes unusable — external keyboard + mouse are mandatory, not optional.
3. Top edge above eye line. Bigger monitors (27"+) frequently need to be LOWERED or pushed farther away; a 32" at 60 cm distance forces head extension. Distance target scales with screen size.
4. Keyboard positive tilt. Little feet folded OUT tilt keyboards toward you and extend wrists — keep them folded (neutral or slight negative tilt).
5. Feet crossed / dangling. Both destroy lumbar position. Footrest or lower chair + footrest.
6. Static "perfect" posture. The best posture is the NEXT posture: vary position; standing desk users should stand 15-30 min per hour, not all day.
7. Eyes at arm's length minimum. Closer than 50 cm forces accommodation strain; if you can't read at 60 cm, that's an eye exam, not a closer monitor.
8. Ignoring glare. Screen facing a window = contrast collapse and adopted neck twist. Screen perpendicular to windows.

Example

$ ergo_setup.py calibrate --height 175
PERSONAL NUMBERS for height 175 cm (sitting):
  Chair seat height:      45.5 cm  (feet flat, knees ~90-100°)
  Desk / keyboard height: 72.6 cm  (elbows 90-110°, shoulders relaxed)
  Monitor TOP edge:       118.0 cm from floor (31.4 cm above desk)
  Screen center:          ~13 cm below eye line
  Viewing distance:       50-85 cm (target ~66 cm)
  Lumbar support:         at belt line (L4-L5), slight recline 100-110°
  Feet:                   flat on floor or footrest, never crossed

$ ergo_setup.py monitor --height 175 --size 27
27" monitor: panel height ~33.5 cm. On a lowest-stand ~5 cm above desk:
  top edge ≈ 39 cm above desk vs eye line 31 cm → 8 cm TOO HIGH.
  Fix: lower the stand; if at minimum, increase distance to ~75-80 cm
  and tilt slightly up toward eyes.

Verification Checklist

• Elbows at 90-110°, shoulders relaxed (not shrugged) at keyboard
• Monitor top edge at or slightly below eye line
• Screen 50+ cm from eyes (arm's length check: press monitor — arm fully extended touches it)
• Feet flat, knees ~90-100°, no crossed legs
• Lumbar support contacts belt line
• Wrists neutral, keyboard feet folded
• 20-20-20: every 20 min, 20 seconds, 6 m away