{"id":243033,"date":"2026-06-22T15:02:15","date_gmt":"2026-06-22T13:02:15","guid":{"rendered":"https:\/\/emariete.com\/co2-gadget-guia-salidas\/"},"modified":"2026-07-07T09:11:08","modified_gmt":"2026-07-07T07:11:08","slug":"co2-gadget-guide-to-outings","status":"publish","type":"post","link":"https:\/\/emariete.com\/en\/co2-gadget-guia-salidas\/","title":{"rendered":"Gadget CO\u2082 Output Guide: Buzzer, NeoPixel and Relays"},"content":{"rendered":"

Connecting an audible or visual alarm to your Gadget CO\u2082 monitor is straightforward: a piezoelectric buzzer, a NeoPixel LED strip or a relay to activate an extractor fan. The unified output system allows you to trigger any of these based on CO\u2082 thresholds with configurable hysteresis.<\/p>\n\n\n\n\n\n\n

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Available departures<\/h2>\n\n\n
Departure<\/th>GPIO pins<\/th>Function<\/th><\/tr><\/thead>
Orange Relay<\/strong><\/td>GPIO 32 (depending on the board)<\/td>It is triggered when the orange level is reached<\/td><\/tr>
Red Relay<\/strong><\/td>GPIO 33 (depending on the board)<\/td>It is triggered when the red level is reached<\/td><\/tr>
NeoPixel<\/strong><\/td>GPIO 26 (depending on the board)<\/td>Configurable WS2812B LED strip<\/td><\/tr>
Buzzer<\/strong><\/td>GPIO 2 (depending on the board)<\/td>Passive buzzer with configurable tone and duration<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

Relay mode vs LED mode<\/h2>\n\n\n

The orange and red outputs can operate in two modes: Relay<\/strong> (the orange outlet remains active even if the red one is activated, ideal for ventilation) or LED<\/strong> (the orange output switches off when the red one is activated). Configurable from Settings \u2192 Output Configuration \u2192 GPIO Outputs<\/strong>.<\/p>\n\n\n

NeoPixel (WS2812B)<\/h2>\n\n\n

Supports WS2812B addressable LED strips with the following type selection: NEOGRB, NEO<\/em>RGB, NEO_RGBW. Brightness adjustable from 0 to 255. Requires 5V (use a step-up converter if running on battery power).<\/p>\n\n\n

Buzzer<\/h2>\n\n\n

Configurable passive buzzer: pitch (300\u20132000 Hz), beep duration (50\u2013300 ms) and mode (OFF, once, every X seconds). It is automatically disabled within the menu to avoid causing a nuisance.<\/p>\n\n\n

Hysteresis<\/h2>\n\n\n

All departures have configurable hysteresis<\/strong> to prevent them from switching on and off continuously if the concentration fluctuates around the threshold.<\/p>\n\n\n

Notes<\/h2>\n\n\n