PACKET.md

Packet

Data transmitted by the flight software to the ground software is called a "packet".

Structure

Constants

As specified in the structure, the format constants are as following:

Packet Start: `^`  
Packet End: `$`  
Packet Delimiter: `|`  
Data Delimiter: `,`

Timestamp

The timestamp is a base-16 encoded number that represents the time elapsed in milliseconds. The Ground Station represents the timestamp as the time elapsed in seconds internally.

Types

SEN

The SEN packet is used to send sensor-related data. The data is in the format of <sensor_type><sensor_location><...value>. The sensor type is a number between 0 and 2 and maps to thermocouple, pressure, or load. The sensor location is a number between 1 and 8 and maps to PT-1, ..., PT-4, TC-1, LC-1, ..., LC-3. The sensor value consists of the rest of the data which is a number in base 16.

VAL

The VAL packet is used to send valve-related data. The data is in the format of <valve_type><valve_location><state>. The valve type is always 0, which maps to solenoid. The valve location is a number in base 16 between 1 and B and maps to SV-1, ..., SV-11. The valve state is a number that represents the current state of the valve.

• Note: Valve data is currently not read, so this packet will not be encountered.

END

The END packet is a special type of packet: it has no data and is in the format ^END|<timestamp>$. This packet tells the Ground Station to terminate the current test and mark its status in the database as Completed. This packet may not be sent at all, so you might not encounter it.

Parsed Packet

Once the Ground Station parses a packet, it sends the structure to the frontend. For a SEN packet, this structure looks like:

{
    header: "SEN",
    payload: {
        load: {
            "LC-1": number,
            // ...
            "LC-3": number
        },
        pressure: {
            "PT-1": number,
            // ...
            "PT-4": number
        },
        thermocouple: {
            "TC-1": number
        }
    },
    timestamp: number
}

For a VAL packet, this structure looks like:

{
    header: "VAL",
    payload: {
        solenoid: {
            "SV-1": number,
            // ...
            "SV-11": number
        }
    },
    timestamp: number
}