Posture Reminder - Webcam Slouch Alert

How to use this tool

Start the camera and sit in a good upright posture.
Click Capture Baseline to save your reference posture.
Adjust the check interval and sensitivity threshold.
The tool checks immediately, then alerts after the selected number of consecutive posture-change checks.

Why posture matters

Prolonged sitting with poor posture can contribute to back pain, neck strain, and fatigue. Regular postural awareness reminders can help you correct your position before discomfort develops.

How the detection works

The tool captures a low-resolution greyscale snapshot at your chosen interval and compares it to your baseline using mean absolute pixel difference. Significant changes indicate you may have moved, slouched, or shifted position.

Privacy

All images are processed locally in your browser using the Canvas API. No video or image data is transmitted anywhere.

Ergonomic setup guide

The neutral seated posture checklist for desk work:

Monitor: top of the screen at or slightly below eye level, arm’s length (45–60 cm) away.
Keyboard and mouse: elbows at approximately 90°, wrists straight and relaxed (not bent upward).
Chair: back supported with a slight lumbar curve, feet flat on the floor or a footrest.
Hips: thighs roughly parallel to the floor, seat pan not pressing into the backs of the knees.

Scientific context

A 2014 study by Dr. Kenneth Hansraj (Surgical Technology International) estimated the compressive force on the cervical spine at various head flexion angles: a neutral upright head exerts ~10–12 lbs of force; flexing forward 60° (typical smartphone use) increases that to approximately 60 lbs. This estimate describes mechanical load; it does not predict injury for an individual. The reminder below measures image differences, not head angle, spinal load, or tissue damage.

Desk stretching routine

Perform these when the reminder fires (takes 2–3 minutes):

Neck rolls: slowly roll your head in a half-circle, ear to chest to ear. 3 reps each side.
Shoulder shrugs: raise both shoulders to your ears, hold 2 seconds, release. 5 reps.
Chest opener: clasp hands behind your back, gently draw shoulders together, hold 10 seconds.
Seated spinal twist: sit upright, rotate torso to the right using the chair back as a support, hold 15 seconds, repeat left.

Frequently asked questions

How does the posture reminder work?

You capture an upright baseline, then the tool compares sampled webcam frames with it using greyscale pixel differences. By default, two consecutive high-difference checks are required before an alert; a good check clears it.

Is this tool accurate?

No. It is a simple image-difference reminder, not a clinical posture assessment. Lighting, camera framing, and background movement can affect the score, and it does not measure spinal angles or diagnose a condition.

Does the webcam feed leave my device?

No. Camera frames are compared in your browser with the Canvas API. Optional desktop notifications contain only a generic posture reminder; no camera image or posture score is uploaded.