For my next project, which is a remote control and telemetry link to a very large robot, I want to have a safe wireless link with a range of at least 300meters. I can use a decent antenna at the control centre, and a dipole on the robot, so range should be no problem.
I have used the RFM22B modules before, but only in the basic simplex mode, I now have 2 of them hooked up on the bench and using the RF22 libraries "reliable datagram" example from Mikem , with 2 Duemilanova boards for now ( they will have embedded chip pcbs in the final units ).
It worked first time, and I have found how to simply read the temperature and signal strength etc.
Now I am looking at how to structure my data, ( which is joysticks and switch data going to the robot, and a few oil pressure, fuel guage, temperature , signal strength and GPS position data coming back )
I was planning to collect the data and put it in a buffer to send, all in the main loop as usual.
In Mikes example below, he has defined the data and datalength between the setup and loop sections ?
Is there significance to this ?
I guess thats the same as having them at the top with the definitions if they are not going to change ?
and I can find no reference to while (1) ? and why // Dont put this on the stack:
// rf22_reliable_datagram_client.pde
// -*- mode: C++ -*-
// Example sketch showing how to create a simple addressed, reliable messaging client
// with the RF22ReliableDatagram class.
// It is designed to work with the other example rf22_reliable_datagram_server
#include <RF22ReliableDatagram.h>
#include <RF22.h>
#include <SPI.h>
#define CLIENT_ADDRESS 1
#define SERVER_ADDRESS 2
// Singleton instance of the radio
RF22ReliableDatagram rf22(CLIENT_ADDRESS);
void setup()
{
Serial.begin(9600);
if (!rf22.init())
Serial.println("RF22 init failed");
// Defaults after init are 434.0MHz, 0.05MHz AFC pull-in, modulation FSK_Rb2_4Fd36
}
uint8_t data[] = "Hello World!";
// Dont put this on the stack:
uint8_t buf[RF22_MAX_MESSAGE_LEN];
void loop()
{
while (1)
{
Serial.println("Sending to rf22_datagram_server");
// Send a message to rf22_server
if (!rf22.sendtoWait(data, sizeof(data), SERVER_ADDRESS))
Serial.println("sendtoWait failed");
else
{
// Now wait for a reply from the server
// Serial.println(rf22.lastRssi(), HEX); // of the ACK
uint8_t len = sizeof(buf);
uint8_t from;
if (rf22.recvfromAckTimeout(buf, &len, 2000, &from))
{
Serial.print("got reply from : 0x");
Serial.print(from, HEX);
Serial.print(": ");
Serial.println((char*)buf);
}
else
{
Serial.println("No reply, is rf22_datagram_server running?");
}
}
delay(500);
}
}