# Hands

> Track up to two hands from a video stream into control lanes: position, depth, pinch, spread, openness and presence per hand.

Source: https://docs.tune.toys/nodes/sense.hands/

Hands tracks up to two hands from a video stream and turns them into control lanes.

## What it does

Connect a video source to `video`. The `control` output has 14 lanes from 0 to 1, in order: l.x, l.y, l.z, l.pinch, l.spread, l.open, l.present, r.x, r.y, r.z, r.pinch, r.spread, r.open, r.present. It runs a MediaPipe model in the browser. The model downloads after the person consents, with its size shown first, and is cached afterwards. Nothing is uploaded. When tracking is lost the lanes hold their last values and `present` falls to 0 after 220 ms.

## When to use it

Use it for hands-in-the-air control of a filter, volume or pitch. See [Sensing](https://docs.tune.toys/concepts/sensing/).

## Ports

<!-- ports:start -->

| Port      | Direction | Signal  | Lanes |
| --------- | --------- | ------- | ----- |
| `video`   | Input     | Video   | 1     |
| `control` | Output    | Control | 14    |

<!-- ports:end -->

## Parameters

<!-- parameters:start -->

| Parameter  | Label   | Range     | Default | Unit | Scale  | Notes                                                                                                        |
| ---------- | ------- | --------- | ------- | ---- | ------ | ------------------------------------------------------------------------------------------------------------ |
| `mirror`   | Mirror  | 0 to 1    | 1       |      | linear | Flip x so the person's right hand is on the right of a mirrored picture. Choices: 0 As captured, 1 Mirrored. |
| `smooth`   | Smooth  | 0 to 1000 | 40      | ms   | linear | One-pole smoothing of every lane.                                                                            |
| `delegate` | Compute | 0 to 1    | 0       |      | linear | Run the model on the GPU or the CPU. Choices: 0 GPU, 1 CPU.                                                  |

<!-- parameters:end -->

### Mirror (`mirror`)

Flips x so the left hand on screen reads as your left when on.

### Smooth (`smooth`)

Smoothing time in milliseconds for the lanes.

### Compute (`delegate`)

Chooses where the model runs: 0 for the default, 1 for the alternative.

## Tips

- Use [Select lanes](https://docs.tune.toys/nodes/ctl.select/) with `"audio": {"channels": 1, "firstChannel": N}` to pick one lane; lanes count from 1.
- A one-lane control cable can drive any parameter through its `{ "node": "x", "port": "@param" }` socket.

## See also

[Select lanes](https://docs.tune.toys/nodes/ctl.select/), [Scale](https://docs.tune.toys/nodes/ctl.scale/), [Smooth](https://docs.tune.toys/nodes/ctl.smooth/), [Sensing](https://docs.tune.toys/concepts/sensing/), [Control lanes](https://docs.tune.toys/concepts/control-lanes/).