Its purpose is to receive the continuous messages sent on the 433 ISM band from multiple homemade sensors,
verify them, format them into a page with headings, and re-ransmit them to commercial devices via bluetooth.
The receiver uses super-regenerative technique and on-off modulation in RS-242 format at 2400 baud.
These signals are processed by a Picaxe 08M2 MCU and buffered in a set of 2 alternate common buffers. The identity of the message is in its first character. The message is delineated by '<' and '>' characters.
These messages are then sent to an Arduino MiniPro MCU at 19,200 baud, still in RS-232 format. Transmission is controlled by the Arduino sending a CTS signal back to the Picaxe. There are 6 messages each with 2 - 4 individual mostly numerical fields separated by commas. These fields vary in length.
The Arduino separates each message field into its own buffer which is part of a struct. Additional items in the struct point to 3 formatting headings. One denotes the source of the message, the second identifies the nature of the field, anf the optional third the units of a numerial value. The struct also contains items to keep track of the fields update history.
The Arduino combines the data, headings from a master list pointed to the formatting items from struch, and punctuation into a page to be sent to an AT-09 Bluetooth module which is HC-10- and BLE 4.3 compatible. The pages are sent at fixed intervals or when a connection is established.
A blue LED flashes each time a message is sent between the MCUs. A green LED shows the Bluetooth connection status.