Vahini · the sensor pen

The pen that understands how you write.

A patented dual-IMU sensor pen that captures motion on ordinary paper. No tablet. No special notebook. No screen. It looks like a pen, thinks like a computer, and feels like every pen you've ever used.

Dual-IMU sensing Writes on any paper Patent No. 584433
A hand writing with the red Vahini sensor pen on a circuit-board surface
ForcePen ControlMotionPen-lift

We didn't want another smart pen.

Every "smart" pen asks you to change something, charge a dock, buy special paper, stare at a screen. We wanted the opposite: all the intelligence, none of the friction. So we removed everything that gets in the way of simply writing.

No charging dock
No special paper
No screen
No camera
No stickers or markers
No change in habit
Just pick it up and write.

How Vahini works

Four steps, from your hand to real insight.

Write

Pick up Vahini and write on any ordinary paper, exactly as you always do.

Capture motion

Dual sensors read pressure, tilt, speed and writing flow 208 times a second.

AI understands

Our engine reconstructs the strokes and reads how the writing was made.

Personalised support

You get a clear report and targeted practice, the loop that makes writing better.

Inside Vahini

Engineering you can feel, not see.

Every decision inside the barrel answers one question: how do you read writing on ordinary paper, with no camera and no screen? Here's how.

Cutaway of the Vahini sensor pen showing its internal circuit board and exploded dual-IMU sensor module
Dual-IMUTwo inertial units capture motion from multiple reference points, so the trajectory holds even with no visual markers.
Tip force sensorReads writing pressure, not just position, the difference between a confident stroke and a struggling one.
Kalman fusionFuses noisy sensor streams into one stable, clean motion trace in real time.
Wireless MCULow-power on-pen processing with Bluetooth LE built in, all the compute, none of the bulk.

The specifications

A dense sensor stack in a familiar pen.

Performance

  • 208 HzMotion sampling rate
  • 16 axesCaptured live, dual-IMU
  • Tip forcePressure dynamics sensing

Intelligence

  • Kalman fusionClean, stable trajectory
  • Motion reconstructionStrokes rebuilt from signal
  • 5 Indic scriptsAI-ready, multi-script

Practical

  • Ordinary paperNo dot-pattern, no tablet
  • Standard refillWrites like any ballpoint
  • Bluetooth LELow-power wireless MCU

Signal intelligence

What Vahini understands.

Six dimensions of how a person writes, read from motion, invisible on a finished page.

Writing Flow

The flow and pace of strokes, fluent and even, or hesitant and effortful.

Pressure

How firmly the pen presses, light and controlled, or heavy and strained.

Stability

Steadiness of the hand, smooth control versus shake and wobble.

Speed

How quickly letters form, and whether pace holds up at exam length.

Fine motor

The micro-movements behind each letter, fatigue, smoothness and control.

Consistency

How repeatable the writing is, letter to letter, line to line, day to day.

The big question

Why didn't we just build another tablet pen?

Because paper is where children actually learn, where exams happen, and where worksheets already live. A screen changes the act of writing. Vahini doesn't.

 Tablet penVahini
Needs a screenYes
Battery anxietyYes
Familiar writing feel
Works on existing worksheets
Ready for paper exams
Classroom-friendly cost

Engineering challenges

Six hard problems, by design.

Reading handwriting from motion alone, no camera, no special paper, means solving things most pens never attempt.

1
Ordinary paperSense position with no printed reference grid to lock onto.
2
No visual markersReconstruct the path from inertia, not from dots or ink tracking.
3
No cameraCapture everything from motion alone, private by design.
4
Low powerRun rich sensing all day inside a slim, pen-sized battery.
5
Real-time BLEStream a dense signal wirelessly without dropping a stroke.
6
Motion reconstructionTurn noisy inertial data into clean, faithful handwriting.

Vahini solves all six, in a pen that just feels like a pen.

The roadmap

Vahini v1 today. A classroom platform next.

v1 is the pen for the individual writer. v2 takes the same sensing into schools, and turns one pen into a connected classroom.

Vahini v1Pre-order

The flagship dual-IMU sensor pen for the individual writer.

  • Dual-IMU sensing, 16 axes at 208 Hz
  • Writes on any ordinary paper
  • Pairs 1:1 with the Vahini Analyser
  • Privacy-safe, captures motion, not words
Vahini v2In development

The same intelligence, built into a connected classroom platform.

  • Multi-pen classroom, many pens, one hub
  • Teacher dashboard & live class analytics
  • OTA firmware & fleet management
  • School charging dock for daily use

The journey

From an idea to a school edition.

2023The idea
2025Patent granted
2025Working prototype
2026Live AI
NextProduction
ThenSchool edition

Experience writing, measured.

Vahini reads how you write, on the paper you already use. Reserve a unit, or watch it in action.