> For the complete documentation index, see [llms.txt](https://wiki.inels.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.inels.com/inels-bus/inels-design-manager-idm3/tutorial-toggles-impulses-and-delays.md).

# Tutorial 2 — toggles, impulses and delays

*Part 2 — Tutorials. Continues the project from* [*Tutorial 1*](/inels-bus/inels-design-manager-idm3/tutorial-your-first-idm3-project.md)*.*

***

## What you will build

Four improvements to the hallway you built last chapter:

|   | Behaviour                                  | You will learn                     |
| - | ------------------------------------------ | ---------------------------------- |
| 1 | One button toggles the light               | `DIGITAL_SWITCH`                   |
| 2 | A staircase light that switches itself off | impulse functions and impulse time |
| 3 | A custom two-minute version                | **defining your own function**     |
| 4 | Long-press turns everything off            | one button, two actions            |

Open your `Tutorial` project before you start.

***

## 1. Toggle — one button, on and off

In Tutorial 1 the button only ever turned the light on. Pressing it again did nothing, because `Digital switch ON` means exactly that.

**Toggle** is a different function: if it is on, turn it off; if it is off, turn it on.

1. **Functions** ribbon tab → **Wire manager**.
2. Select your `Hallway light ON` wire.
3. Under **Functions:**, select the existing `DIGITAL_ON` entry and click **–** to remove it.
4. Click **+**. In the **Wire function** window:
   * **Action:** `Short down`
   * **User function:** `DIGITAL_SWITCH`
5. **OK**, and close the Wire manager.
6. Rename the wire to `Hallway light toggle` while you are there — wire names matter once there are two hundred of them.

Save and upload (`[☰]` → **Save to central unit**). Press the button repeatedly: on, off, on, off.

> **Why `Short down` and not `Short up`?** `Short down` fires the moment the button goes in; `Short up` fires when it is released. For lighting, `Short down` feels more responsive. For anything where you want to be sure the user meant it, `Short up` is safer. Both are correct — pick deliberately.

***

## 2. A staircase light

An **impulse** switches something on and then off again by itself, after a time you choose. That is the classic staircase light: press once, get light for long enough to reach the top.

The default project already has these:

| Function               | On for    |
| ---------------------- | --------- |
| `DIGITAL_IMPULSE_1S`   | 1 second  |
| `DIGITAL_IMPULSE_5S`   | 5 seconds |
| `DIGITAL_IMPULSE_1MIN` | 1 minute  |
| `DIGITAL_IMPULSE_5MIN` | 5 minutes |

Wire one up to the second button on your GSB3-40:

1. **Design** workspace tab → place another output icon and **Connect** it to the SA3-02M's **second** output. Name it `Stair light`. *(If your relay has only one output, reuse the hallway light — the behaviour is the same.)*
2. Place another button icon, **Connect** it to **button 2** of the GSB3-40, name it `Stair button`.
3. **Function** workspace tab → **Functions** ribbon tab → **Add connection**.
4. Drag from `Stair button` to `Stair light`. Turn **Add connection** off again.
5. **Wire manager** → select the new wire → name it `Stair light 1 min` → **+**:
   * **Action:** `Short down`
   * **User function:** `DIGITAL_IMPULSE_1MIN`
6. **OK**, close, save, upload.

Press button 2. The light comes on, stays on for a minute, and goes out by itself.

### What impulse actually does

There are three impulse functions and the difference matters:

| Function              | Behaviour                                                                                                                 |
| --------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| `Digital_Impulse_ON`  | **If the output is already on, nothing happens.** If it is off: wait *delay*, switch on, wait *impulse time*, switch off. |
| `Digital_Impulse_OFF` | The mirror image. If already off, nothing happens. If on: wait *delay*, switch off, wait *impulse time*, switch on.       |
| `Digital impulse`     | Ignores the current state. Waits *delay*, flips the output, waits *impulse time*, flips it back.                          |

Both parameters accept anything from 0 seconds to 24 hours.

The predefined `DIGITAL_IMPULSE_*` functions are all built on **`Digital_Impulse_ON`** with a delay of zero. That is why pressing the button again mid-cycle does not restart the timer — the output is already on, so the function does nothing.

> **Want a re-triggerable staircase light** — where each press restarts the minute? An impulse will not do it. Use a timer instead ([Tutorial 8](/inels-bus/inels-design-manager-idm3/tutorial-timers-counters-and-conditions.md)).

***

## 3. Define your own function

One minute is too short, five is too long. You want two. Nothing predefined does that, so make it.

1. **Functions** ribbon tab → **Function manager**.
2. Click **+**. The right-hand panel becomes editable.
3. Fill in:
   * **Name:** `DIGITAL_IMPULSE_2MIN`
   * **Function type:** `Digital`
   * **Select function:** `Digital_Impulse_ON`
4. Two parameters appear:
   * **Digital delay (s)** → `00:00:00`
   * **Digital impulse time (s)** → `00:02:00`
5. Click **✓** to save. It joins the list on the left.

Now swap it onto the wire: **Wire manager** → the stair wire → remove `DIGITAL_IMPULSE_1MIN`, add `DIGITAL_IMPULSE_2MIN` on `Short down`. Save, upload, test.

> **Name functions after what they do, not where you used them.** `DIGITAL_IMPULSE_2MIN` is reusable anywhere. `STAIR_LIGHT` is not — and in a year nobody will remember what it does. The predefined names follow this convention; follow it too.

### The delay parameter

You skipped over **delay** by leaving it at zero. It is genuinely useful: a delay of `00:00:03` on an impulse means *wait three seconds, then give a minute of light*.

Combine that with `Digital delay switch OFF` and you can build a corridor that lights ahead of someone and goes dark behind them.

***

## 4. One button, two behaviours

A button has four actions. Nothing stops you using several on the same wire — this is how one switch does more than one job.

Add a long-press "everything off" to your toggle wire:

1. **Wire manager** → select `Hallway light toggle`.
2. **+**:
   * **Action:** `Long down`
   * **User function:** `DIGITAL_OFF`
3. **OK**, close, save, upload.

Now: **short press toggles the light, long press always turns it off.** Same button, same wire, two rules.

| Action              | Means             | Fires when                   | Typical use                              |
| ------------------- | ----------------- | ---------------------------- | ---------------------------------------- |
| `Short down`        | short **press**   | the button goes down         | the normal action                        |
| `Short up`          | short **release** | it comes back up             | when you want confirmation on release    |
| `Long down`         | long **press**    | still held after \~1.5 s     | a second function — "all off", "scene"   |
| `Long up`           | long **release**  | released after a long press  | ending a held action, e.g. stop dimming  |
| `Permanent actions` | —                 | repeatedly, driven by the CU | continuous behaviour while a state holds |

`Long up` looks pointless until you dim a light by holding a button — [Tutorial 3](/inels-bus/inels-design-manager-idm3/tutorial-dimming-with-analog-functions.md) uses exactly that: `Long down` starts the brightness climbing and `Long up` stops it.

***

## 5. Delayed off

One more useful pattern. `Digital delay switch OFF` turns something off *after* a delay — it does not touch it now.

Make a `DIGITAL_OFF_AFTER_30S`:

1. **Function manager** → **+**
   * **Name:** `DIGITAL_OFF_AFTER_30S`
   * **Function type:** `Digital`
   * **Select function:** `Digital delay switch OFF`
   * **Digital delay (s):** `00:00:30`
2. **✓**

Put it on a wire with `Short down` and the light goes off half a minute after you press. Combine it with a motion sensor rather than a button and you have the "keep the light alive while there is movement" behaviour from the worked example in [Chapter 2](/inels-bus/inels-design-manager-idm3/how-programming-works-in-idm3.md#25-worked-example-read-a-real-one).

The three delay functions:

| Function                     | Effect after the delay |
| ---------------------------- | ---------------------- |
| `Digital delay switch ON`    | switches on            |
| `Digital delay switch OFF`   | switches off           |
| `Digital delay switch value` | toggles                |

***

## What you learned

* `DIGITAL_SWITCH` toggles; `DIGITAL_ON` does not
* Impulse functions switch and switch back — `impulse time` sets how long
* `Digital_Impulse_ON` **ignores a press while the output is already on**
* You define your own functions in **Function manager**, and name them after what they do
* One wire carries several actions — that is how one button does several jobs
* Delay functions act *later*, not now

***

## Try this before moving on

1. Build `DIGITAL_IMPULSE_10MIN` and put it on an outside light.
2. Add `DIGITAL_ON` on `Short up` to a wire that already has `DIGITAL_OFF` on `Short down`, and work out what the light does. (Read the actions carefully before you upload.)
3. Open **Wire manager** and give every wire a real name. Future you will be grateful.

***

**Next:** [Chapter 7 — Tutorial 3: dimming](/inels-bus/inels-design-manager-idm3/tutorial-dimming-with-analog-functions.md) — analog outputs, levels, and ramps.