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PLANCHETTE

A spelling board driven by the phone's sensors. There is no word list anywhere in this app. Every word you see was built one character at a time.

The idea in one sentence

The board is an alphabet, a sensor reading is a marker moving across it, and a letter is only chosen if the marker stops and stays on it.

THE MARKER IS HOLDING ON A — THE BAR IS FILLING

Step by step

Your phone has sensors that never stop reading — the magnetic field around it, the light hitting it, the tiniest vibrations, the sound in the room.

The app watches one sensor and learns what its normal range looks like over the last thirty seconds or so.

Right now, the reading sits somewhere in that range — near the bottom, in the middle, near the top. That position becomes a spot on the board. Bottom of the range is the far left, top is the far right.

As the reading changes, the marker slides. You'll see it moving constantly, because sensors are always drifting a little.

When the marker lands on a cell, a red bar starts filling that cell. If the marker stays put until the bar is full, that character is chosen and joins the word. If it drifts off, the bar empties and nothing happens.

The word builds up on screen. When the marker holds on the space cell, the word is finished and spoken aloud.

Why the holding matters

This is the whole point of the design.

Random noise jumps around. It lands somewhere different every tenth of a second, so it can never stay in one cell long enough to fill the bar. I tested this against pure randomness for thirty minutes and not one character was ever chosen.

To spell anything at all, a reading has to be held steady at a particular level. That's a deliberate act, not an accident. It's the difference between a board that says something and a board that just rattles.

What the settings do

Driving sensor — which sensor moves the marker. Magnetic is the traditional choice. Entropy is the phone's random number generator, which has no physical input at all.

Hold time — how long the marker must stay put. Shorter means more characters and more nonsense. Longer means fewer characters and more meaning if any arrives. Start at 700ms.

Memory window — how far back the app looks to decide what "normal" is. A short window makes it react to sudden changes. A long window lets slow drifts register.

What it records

Every character is logged with the exact sensor value that produced it, where that value sat in the range, and when it committed. Export gives you the whole trail. Any word can be taken apart afterwards and checked — by you, or by somebody who doesn't believe you.

What this does not prove

A sensor can be held steady by ordinary things. A magnet near the phone. A hand over the light sensor. A machine humming at a constant pitch. Your own hand holding the phone. All of these will spell.

Letters are also the easiest material in the world for a human mind to turn into words. You will see meaning in strings that have none. That isn't a flaw in you — it's how reading works.

So run a control. Same room, same sensor, same hold time, phone left alone, nobody there. If it spells just as much to an empty room, the board is reading drift, not an answer.

That comparison is the only thing that turns this from a toy into a measurement.