Env Monitor

This open source project is an environmental monitor that can be used in a domestic setting. It may be helpful for a user to have a better understanding of the local conditions. It is a low resource and basic monitor. It will provide regular readings of the sensors as an output. The board is designed around an stm32 mcu as it gives good low power performance. The embedded crystal and voltage regulation of the stm32 means the circuit design and board layout is quite straight forward. It is populated with a light dependant resistor, temperature sensor and humidity sensor. The boards runs from a 3.3V supply. Two of the sensors use a 5V supply. It is proposed to program the project with micropython to send readings at intervals. Usart and I2C outputs are being used. There are mounting holes provided on the board for future uses. The light sensor is an LDR which uses a voltage divider arrangement to send its light level to the stm32's ADC pin input for conversion to a digital value. The lower side of the board is used as the ground plane. Decoupling capacitors are provided for the mcu as per the user guide of the mcu. The board is 5cm x 5 cm with an upper silk screen referencing the components. It is foreseen that the board would be low cost to make and low cost to run yet provide enough functionality to provide a useful and consistent output over its lifetime. This project is released as open source. The components or their equivalent are readily available.