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OutGauge - Arduino: Get Speed from a UDP packet
(9 posts, started )
#1 - pancheitor
OutGauge - Arduino: Get Speed from a UDP packet
Hi all!
I'm trying to get the speed from an UDP packet on my arduino.
I show how I receive the float speed variable:

char speed[4];
speed[0] = packetBuffer[12];
speed[1] = packetBuffer[13];
speed[2] = packetBuffer[14];
speed[3] = packetBuffer[15];

And I obtain an output like it (Serial.println(speed):

z{Aý

I tried by many ways but I don't get the speed in numbers.

Somebody can let me know how I can get the float speed variable and show it in the serial port?


Thanks!!!
#2 - MadCatX
What language are you writing your application in?

C

char raw_speed[4];
raw_speed[0]= og_packet[12];
raw_speed[1]= og_packet[13];
raw_speed[2]= og_packet[14];
raw_speed[3]= og_packet[15];

float speed = *(float*)raw_speed;
Serial.println(speed);

C++

char raw_speed[4];
raw_speed[0]= og_packet[12];
raw_speed[1]= og_packet[13];
raw_speed[2]= og_packet[14];
raw_speed[3]= og_packet[15];

float speed = reinterpret_cast<float&>(raw_speed);
Serial.println(speed);

#3 - MadCatX
Also a solution for Java

byte[] rawSpeed = new byte[4];
rawSpeed[0] = og_packet[12];
rawSpeed[1] = og_packet[13];
rawSpeed[2] = og_packet[14];
rawSpeed[3] = og_packet[15];

int bits = 0;
for(int i = 3; i >= 0; i--) {
bits |= rawSpeed[i] << 8*i;
}

float speed = Float.intBitsToFloat(bits);
Serial.println(speed);

#4 - pancheitor
The Arduino language (based on Wiring) is implemented in C/C++, and therefore has some differences from the Processing language, which is based on Java.
#5 - MadCatX
The C approach should work fine then...
#6 - stan.distortion
Would have thought floats should be avoided whenever possible on the Arduino, there is no floating point unit on AVR's and software based floating point calcs waste a hell of a lot of cycles.
#7 - pancheitor
Great!!! It works fine!! Thanks!!!!!
#8 - Scoundrel
Quote from pancheitor :Hi all!
I'm trying to get the speed from an UDP packet on my arduino.
I show how I receive the float speed variable:

char speed[4];
speed[0] = packetBuffer[12];
speed[1] = packetBuffer[13];
speed[2] = packetBuffer[14];
speed[3] = packetBuffer[15];

And I obtain an output like it (Serial.println(speed):

z{Aý

I tried by many ways but I don't get the speed in numbers.

Somebody can let me know how I can get the float speed variable and show it in the serial port?


Thanks!!!

How do you receive UDP packets in Arduino?

Como lees los paquetes UDP en Arduino?
#9 - DrOversteer

OutGauge - Arduino: Get Speed from a UDP packet
(9 posts, started )
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