Emergency Button

A bright, unmissable button for safety-critical actions: emergency stop, panic alert, machine shutdown. Five geometric styles, three trigger modes, visual safety cues you can tune so a casual tap doesn’t fire it.

[image] Emergency Button on canvas, Round style, red, pulse glow visible

What it does

Emergency Button is a styled push button focused on one job: making a safety action obvious and hard to fire by accident. You pick a shape, a trigger filter (single press / long press / double press), and visual cues (pulse, warning stripes, border).

When the trigger condition is met, your sketch reacts in WHEN_PRESSED. The widget visually flips to a Triggered color, and (optionally) auto-resets after a delay.

When to use it

• Hardware emergency stop — Trigger mode Long, label HOLD TO STOP. Cut power to relays from WHEN_PRESSED and set a fault flag.
• Panic alert — Trigger mode Double. Fire a notification or buzzer; reset is automatic.

Properties

The Inspector opens as a bottom sheet with a Widget ID field at the top, then these sections in order.

Widget ID

1. Essential

2. Header

3. Button label

4. Appearance

5. Behavior

6. Colors · States

7. Colors · Details

States and behavior

[image] Three states: Idle (red, pulsing) / Pressed (dark red) / Triggered (green)

• Idle — Armed, waiting. Idle color, with optional pulse and warning stripes.
• Pressed — During the touch. Pressed color.
• Triggered — The trigger condition was met. Triggered color, persists until Auto reset delay or user taps again.

The trigger filter prevents most accidental fires:

• Press — Fires on any single press. Fastest, easiest to fire by accident.
• Long — Must be held briefly before firing. Safer for serious actions.
• Double — Two quick presses. Filters most accidental taps.

In code

The button mirrors what the user does on the dashboard. To react to it in your sketch:

IEmergencyButton("estop") {
  WHEN_PRESSED {
    stopAllMotors();
  }
};

That’s the minimum — one event block, the action fires when the trigger condition is met. See InstantIoT Library / Receive Command from App for details.

Working Arduino code example

A complete sketch you can flash. The Widget ID estop matches the one you set on your Emergency Button in the app.

[gif] Emergency Button on the dashboard cutting power to relays on the ESP32

Direct Mode

Your phone connects directly to the ESP32’s SoftAP — no router, no server. Best for prototyping and standalone setups.

#include <InstantIoTWiFiAP.hpp>

const char* AP_SSID = "InstantIoT-Greenhouse";
const char* AP_PASS = "12345678";

#define RELAY_PIN 5
#define ALARM_PIN 6

InstantIoTWiFiAP instant(AP_SSID, AP_PASS);

void stopAllMotors() {
  digitalWrite(RELAY_PIN, LOW);
  digitalWrite(ALARM_PIN, HIGH);
}

IEmergencyButton("estop") {
  WHEN_PRESSED {
    stopAllMotors();
  }
};

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(ALARM_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, HIGH);
  digitalWrite(ALARM_PIN, LOW);
  instant.begin();
}

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

Server Mode

The ESP32 connects to your self-hosted InstantIoT Server over WiFi. Multiple devices, persistent state, history.

#include <InstantIoTWiFiServer.hpp>

const char*    WIFI_SSID     = "YOUR_WIFI_SSID";
const char*    WIFI_PASS     = "YOUR_WIFI_PASSWORD";
const char*    SERVER_IP     = "192.168.1.42";
const uint16_t SERVER_PORT   = 9001;
const char*    DEVICE_TOKEN  = "YOUR_DEVICE_TOKEN";

#define RELAY_PIN 5
#define ALARM_PIN 6

InstantIoTWiFiServer instant(SERVER_IP, SERVER_PORT, DEVICE_TOKEN);

void stopAllMotors() {
  digitalWrite(RELAY_PIN, LOW);
  digitalWrite(ALARM_PIN, HIGH);
}

IEmergencyButton("estop") {
  WHEN_PRESSED {
    stopAllMotors();
  }
};

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(ALARM_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, HIGH);
  digitalWrite(ALARM_PIN, LOW);
  instant.begin(WIFI_SSID, WIFI_PASS);
}

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

The widget code is identical — only the include and constructor change.

Notes

• Reset delay is hidden when Auto reset is off.
• Pulse and warning stripes are visual cues only — they don’t change the button’s behavior, just signal that this is a serious action.

Next

→ Simple Button — When you don’t need the safety filters.

→ Switch — For non-critical persistent on/off.