Hi guys,

I know that for a simple transmission e.g. humidity and temperature, the Arduino can simply fit these into a float array and send it to the RPi.

The RPi can then execute the following code snippet to get the value:

DataBytes=8
receivedMessage=bytearray(DataBytes)
radio.read(receivedMessage,radio.getDynamicPayloadSize())
data = struct.unpack('ff',receivedMessage)
humidity=data[0]
temperature=data[1]

Arduino snippet:

struct values{
char name[15];
float temp;
float humi;
float light;
float soilMoist;
float soilTemp;
float gasSensor;
float pirSensor;
};
struct values DataToSend;
DataToSend.temp=dht.ReadTemperature();
//continue storing data in DataToSend
radio.write(&DataToSend,sizeof(DataToSend))

My question is now, how would I send this struct from the Arduino to the RPi with a similar method like the float array?

Hi guys,

Currently I have been at this for days now, and I just don't know how to decode the struct value upon receiving the struct data from my Arduino. I am using Python on the RPi side, both are fitted with the same NRF24L01 and I am using RF24 Library https://github.com/matmany/lib_nrf24 which is forked from BLavery.

So my code on the Arduino side is relatively standard, the Arduino transmits a struct data of sensorName[15], Air temperature, Air Humidity, Light sensor, soil Moisture, soil Temperature, gas Sensor and motion Sensor to a defined pipe. Apart from sensorName, these are all declared as Integers as I will convert it to float in RPi to shorten the size of the struct, thus the struct size is 31, just 1 byte away from the maximum.

Upon running my code at the RPi, I get all sorts of bytes values and I want to convert it to their actual values, which is integer->float.

RPi code is just something like

receivedMessage=[]
radio.read(receivedMessage,radio.getDynamicPayloadSize())
print(receivedMessage)

OUTPUT:
different kinds of values
[0,2,3,195,0,0,0,etc.]

With a previous small side thing I did a few months ago, I only had to transmit temperature and humidity in a float array, and I did it like this, which works!

DataBytes = 8
receivedMessage=bytearray(DataBytes)
radio.read(receivedMessage,radio.getDynamicPayloadSize())
data = struct.unpack('ff', receivedMessage)
humidity=data[0]
temp=data[1]

So my question is, how would I do the same in the case of receiving struct?