# Oil sensor

Using an ultra sonic sensor, it detects the amount of oil used for heating.

For optimization purposes, it uses 2 microcontrollers:
#### **Arduino Pro Mini**
It offers a precise quartz clock, required by the ultra sonic sensor to accurately determine the level of oil in the tank. But because it has a high consumption, it is not suited for battery powered devices.
#### **ATTiny85**
It has an inaccurate quartz clock that cannot be used for the sonar sensor, but it is more than enough to be used as a wake-up device for Arduino Pro Mini. Due to the very low power consumption, it is ideal for battery powered devices.

## Mode of operation
ATTiny85 is connected directly to the battery and acts as a power switch:
1. on regular intervals, ~6 hours, it powers on the Arduino Pro Mini
1. Arduino Pro Mini will:
    - read the oil tank level
    - send the information to the RC Gateway
    - signal the ATTiny85 that it has finished
1. turns off the Arduino Pro Mini

![Schematics](docs/oil_sensor_bb.png)