Packet structure

The packet is sent in byte form.

Header

The header is used to identify what kind of packet this is and to know the time that it was sent.

startByte: uint8  (1 byte) -> 0x00
lenght: uint8  (1 byte) -> The length of the packet in bytes
packetId: uint8  (1 byte) -> 0x00 for a data packet and 0x01 for a debug packet 0x01
senderId: uint8  (1 byte) -> used to varify the sender can be changed, curerently set to 0xE6
timestamp: uint32 (4 bytes) -> the millis, since the canSat was turned on

8 bytes

Payload

The type of payload is identified by the packetId byte. The payload can be either Data or Debug.

Data

All the collected data is sent using this packet. It will be sent multiple times per second.

angVelocity: [int16 int16 int16] (6 bytes) -> 100 * °/s
acceleration: [int16 int16 int16] (6 bytes) -> 100 * g
magneticField: [int16 int16 int16] (6 bytes) -> 100 * mTesla
gps: [float32 float32 float32] (12 bytes)
temperature: int16 (2 bytes) -> 100 * °C
pressure: uint16 (2 bytes) -> Pa
humidity: uint8 (1 byte) -> %;
vocConcentration: uint16 (2 bytes) -> ppm
co2Concentration: uint16 (2 bytes) -> ppm
checkSum: uint8 (1 byte) -> calculated by using xor on all the bytes of the packet.

40 bytes (total 48 with header bytes)

Debug

This is used to diagnose issues with the CanSat and see if everything is working correctly

packetCount: uint16 (2 bytes) -> How many data packets were sent in total
batteryVoltage: uint16 (2 bytes) -> 100*V 
memUsage: uint16 (2 bytes) -> kB
sensors: uint8 (1 byte) -> Each bit represents the functioning of deffirent sensors. [0, 0, sdCard, co2, voc, dht11, gy91, Parashute]
errors: uint8 [dynamic] (X bytes) -> Up to 48 characters (bytes)
checksum: uint8 (1 byte) -> calculated by using xor on all the bytes of the packet.

8 to 56 bytes (total 64 with header bytes)

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