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Internet connected fire/smoke alarm project

This project is an upgrade to a previous project of mine – the DIY IoT smoke alarm. It is a more advanced version that uses dedicated hardware rather than the generic “Funky” project + external components. In essence, the module integrates into cheap smoke detectors and provides wireless event transmission plus periodic battery measurements to cloud infrastructure using BBoilRF as a gateway (over MQTT).

The hardware features

  •  ATmega328 MCU
  • Wireless 433Mhz FSK module (RFM69)
  • Status LED
  • Configurable node address via DIP switches (16 addresses) for easy setup
  • Level shifting hardware to ensure 9V signals are safely detected by the MCU
  • Zero drain battery voltage measurement sorcery
  • Temperature sensor
  • Power from 9V via LDO or <3V via boost regulator for alternative use cases

The advantages of this connected smoke alarm are obvious

  • Remote notification in the case of event detection
  • Identification of the alarm by node ID
  • Smoke detector battery monitoring, notification that replacement is necessary
  • Alternative method of fire monitoring using the onboard temperature sensor to identify abnormal readings rise i.e. before smoke event
  • Notification about lack of communication with smoke detector
  • Actuator engagement in case of event detection e.g. shut off gas supply
  • Wireless range of up to 250m in outdoor conditions
  • Encrypted communication with gateway, reduced risk of false alarms
  • Low cost
  • Long battery life

4 thoughts on “Internet connected fire/smoke alarm project

  1. Bo Herrmannsen

    what board is that? and how is the connection to the internet done? is that the BBoilRF ?

    could it not connect direct via wifi if a esp module was used?

    1. Martin Post author

      It is a custom made PCB. Uses BBoil as a gateway, so that it can benefit from low power consumption. This way I’ll be able to get battery status, a temperature reading and generally a heartbeat from the device at least once every 30 min. This is not achievable with WiFi. Check this video for interesting analysis on this subject: