Emergency Button

A big red button that means stop. Hold it and it triggers — pulsing — and stays triggered until it is reset. It is designed to be impossible to miss and hard to press by accident.

What it does

Triggering writes the Trigger value (1) and the button stays in its triggered state. Resetting writes the Reset value (0) and it goes back to idle. You choose whether a single tap or a hold triggers it, and whether it rearms by itself (goes back to idle after a moment) or waits for a second tap. The device sees both transitions with WHEN_TRIGGERED and WHEN_RESET.

When to use it

• Stop everything — cut a motor, close a valve, park an arm.
• Arm / disarm — an alarm, a sprinkler, a heater.
• A state you must see — the pulsing red says triggered from across the room.

Set it up

1. Place it — In edit mode, tap + and choose Emergency Button under Controllers. Make it big, and put it on the first page: its whole point is to be found without looking.
2. Wire it to a signal — Tap the button, open the Data tab, tap + Add a target and pick an Integer signal on your device.
3. Decide how it triggers — In the same tab, under To trigger, keep Hold down — a deliberate press — or choose One tap. Leave Rearms by itself on if the button should go back to idle on its own.
4. Try it — Close the settings, tap ▶, and hold the button: the device receives 1.

Settings

Tap the widget in edit mode: the sheet opens with a live preview at the top, then two tabs — Data for what it reads or writes, Appearance for how it looks.

Data — what it writes

Targets

What each gesture sends

To trigger

Appearance — how it looks

Title

Display

Colors

States

• Idle — red, still. Triggered — pulsing until reset.
• Hold down — the button fills while you hold it; release early and nothing is sent.
• Device offline — the trigger goes to the Cloud; use ISignal and Restore so a device that reboots comes back stopped.

Arduino device code

The address is all the device knows — I0 here; use the one the app gave your signal. In the sketch, two clauses, two transitions:

IEmergencyButton(I0) {
    WHEN_TRIGGERED { … }
    WHEN_RESET     { … }
};

Complete sketch — Cloud

Paste it into the Arduino IDE, put your Wi-Fi and the token the app gave you, upload.

#include <InstantIoT.h>

const char* WIFI_SSID    = "MyWiFi";
const char* WIFI_PASS    = "MyPassword";
const char* DEVICE_TOKEN = "PASTE_TOKEN_HERE";

const int MOTOR = 5;

IEmergencyButton(I0) {
    WHEN_TRIGGERED { digitalWrite(MOTOR, LOW);  Serial.println("STOP");  }
    WHEN_RESET     { digitalWrite(MOTOR, HIGH); Serial.println("reset"); }
};

void setup() {
    Serial.begin(115200);
    pinMode(MOTOR, OUTPUT);
    InstantIoT.begin(WiFiLink(WIFI_SSID, WIFI_PASS), Cloud(DEVICE_TOKEN));
}

void loop() {
    InstantIoT.loop();
}

Other connections

The widget block never changes. Only the begin() line says how the device reaches the app:

Direct needs no token: the phone is at the other end of the wire. See Connect for TLS, timeouts and what to do when it does not connect.

ISignal does the same job — and survives a restart. ISignal(I0, int v) runs with exactly the same value as IEmergencyButton(I0): the widget block is the readable form, ISignal the generic one, and you can use either. The difference shows when the device reconnects: with Restore after a restart on the signal, the Cloud sends the last value again and only the ISignal block runs — an emergency stop is a state you want back after a restart. Read it with ISignal(I0, int v), turn Restore after a restart on, and a device that reboots while the stop is armed comes back stopped. See One block for everything.

Notes

• Put the safety in the sketch too: the device should stop by itself if the connection drops (a watchdog on InstantIoT.loop()).
• One emergency button per dashboard, big, on the first page. Its whole value is being found without looking.

Next

→ Switch — a plain on / off → Simple Button — a gesture without the drama