# Temperature sensor

It uses a [TMP36](https://cloud.hodos.ro/wiki/ha/datasheets/TMP35_36_37.pdf) to read temperature and it is optimised for power consumption.  
It uses watch dog that wakes every 8s and increments a counter. Once the counter reaches a certain value (e.g. equivalent to 5 mins), it will read and send temperature to the gateway.  
Every hour the voltage is also read and sent.

According to the calculator here, https://www.geekstips.com/battery-life-calculator-sleep-mode/, a cell coin battery with a capacity of `240mAh` should last for 
`~ 3 months (108 days)`, given that:
- Current consumption of device during sleep is `4.5uA`
- Device wakes up every `5 mins (12 times/hour)`
- Current consumption of device during wake is `10mA`
- Duration of wake time is `1000 ms`

![Schematics](docs/temp_sensor_bb.png)