HM330x Sleep Fixes and SPS30 Support

The AttNode v3 firmware now has support for the Sensirion SPS30 Particulate Matter Sensor . At the moment the PM1, PM2.5, PM4 and PM10 values in µg/m³ are reported by the sensor. There is only support for the I2C-Mode for now. Since the Sensor needs a 5V power supply, you’ll need a power source that can provide that (e.g. USB), and connect the ATTNode via a PowerPack. the I2C-Pins of the Sensor can be directly connected to the ATTNode

The firmware support can be enabled with #define HAS_SPS30 in config.h as usual.

Furthermore the Library for the HM3301 Particulate Matter Sensor now has working support for the sensors Sleep-Mode via the “SET”-Pin. You can select a pin to connect it to on the AttNode via config.h. If the define HM330x_SLEEP_PIN is set to a valid pin it will be used to put the sensor into sleep mode while the node is sleeping.

Please be aware that when using Sleep mode (and also for the SPS30), the Node will wait ~30s for the values to stabilise before sending the data as the datasheets recommend. This also means, that on startup the node will take >30s until the first message arrives.