A place users can post their projects. If you have a small project and would like your own dedicated place to post and have others chat about it then this is your spot.

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By martin_g
#64314 In my latest project I tried to extend a cheap standard smoke detector with an ESP8266 WiFi-chip to make it smart. It integrates the smoke detector device into the IoT for less than 15€/$ overall costs.

The project is based on a feature of nearly any smoke detector circuit (e.g. the MC145010 or the CS2105G0-M12), namely the I/O pin, that it typically unused in cheap devices. It can be used to power up an ESP only in an alarm situation (or when the test button is pressed). Thus, the whole WiFi circuit doesn't draw any additional current during standby, therefor it runs on batteries for month's and years.

In addition, the basic safety critical functionallity of a local alarm with the build-in horn remains completely untouched.

See the video for details.


The software is rather basic for the moment: Just a simple MQTT publisher with hardcoded adresses. It is not even worth publishing: just take the basic MQTT publisher sample from the Arduino environment and you are done. A switch that powers up the ESP for configuration (should pull up between the diode and the resistor), a Web interface for setup and OTA-updates would be perfect, but as there are many frameworks for that out there, this was not the main focus here. It is rather a PoC of a really battery power IoT device (for less than 5$ additional costs).
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By satsuma
#64736 Hi marting,

great idea to reduce the sleep current from 20uA (ESP8266 sleep current) to practically 0. I used your idea in a similar way in one of my projects already and it works really great.
As you told in your video, the real invention is not the use for a somoke detector, but the way to reduce the sleep current.

Many thanks !

satsuma