How to pass 2 parameters with RCSwitch library?

Question

I'm learning Arduino's world, but knowing very little about C and C++.

I'm trying to achieve a little RF transmitter which should send the temperature and humidity from a DHT-11 sensor to a Raspberry Pi.

I'm using the RCSwitch library to send information with the Arduino, and the 433Utils library to receive it on the RPI.

Using those 2 libraries demos, I was able to send an integer, holding temperature or humidity information (mySwitch.send("00001010");), and read it on the RPI.

But how can I send both informations so that the RPI will know which one is the temperature and the humidity ?

I know I could just send both and assume the lowest is the temperature, but this would be very messy and not very rewarding.

EDIT :

Following Edgar's answer in https://arduino.stackexchange.com/a/52992/11604, I know write:

void send_string(const char *str){
 int i = 0;
 for (char *p = str; *p; p++ ) { 
 mySwitch.send((i<<8) + *p, 16);
 i++;
 }
}
void loop() { 
 delay(1000); 
 h=40.650;
 t=32.0078; 
 hic=33.586; 
 String x = "$H" + String(h) + "T" + String(t) + "HI" + String(hic); 
 send_string(x.c_str());
}

Works perfectly ! (see his complete answer for the RPI-side code)

• Juraj: mySwitch.send("T45H50");, mySwitch.send("[45;50]");, mySwitch.send("T45"); mySwitch.send("H50");...
• Majenko: Are you really sending an integer, or are you sending an ASCII representation of the binary bits of an integer?
• Dan Chaltiel: The send() method take either an integer, a string byte representation or a tri-state code, I cannot send a string directly

Answer 1

The library you have chosen is not designed for transmitting information between nodes. It is intended for sending simple ON/OFF commands to RF-connected switches. Bending it to send data in the way you want would be difficult. Not impossible, but difficult.

Instead you should be considering a more suitable system, such as the popular RadioHead library. It appears to have Raspberry Pi support out of the box:

Raspberry Pi Uses BCM2835 library for GPIO http://www.airspayce.com/mikem/bcm2835/ Currently works only with RH_NRF24 driver or other drivers that do not require interrupt support. Contributed by Mike Poublon.

Alternatively a small Arduino as an interface between the RF module and the Pi may be another option.

• Dan Chaltiel: I think this library is what I was looking for, thanks ! But I don't understand your last sentence, in what is this different than what I'm doing ?
• Dan Chaltiel: Actually, RadioHead is far too complicated when you don't fully understand what you are doing (hope I'll get it someday). I found a very good answer with RCSwitch [arduino.stackexchange.com/questions/52989/….