# Timer

run code on a delay or at a repeating interval.

```{raw} html
<a class="example-run-button" href="../demos/features_2d_timer.html">▶ Run in browser</a>

```

**Tags:** `2d` `timer` `signals`

A `Timer` is a node that emits a `timeout` signal after its `duration`. Set
`one_shot=False` to repeat. Here a repeating timer spawns a pulse every 0.8s, and
each pulse uses its own one-shot timer to remove itself after one second, so the
screen stays lively without any per-frame bookkeeping in the root.


## What it demonstrates

- `Timer(duration=, one_shot=, autostart=)` -- a node that fires `timeout` after a delay.
- `timer.timeout.connect(fn)` -- run something when it fires (a signal, like any other).
- Repeating timers (`one_shot=False`) for intervals; one-shot timers for delayed actions.

## Source

```{literalinclude} ../../examples/features/2d/timer.py
:language: python
:linenos:
```