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
How do you differentiate between a fire allarm and a low battery event?
The low battery chirps are short, while the alarm event ones are much longer, so quite easy.
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?
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:https://www.youtube.com/watch?v=c-eFvTYJcYs