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Refactored common code from leaf/relay nodes into static functions. Improved comments.

This commit is contained in:
maniacbug 2011-05-15 07:22:11 -07:00
parent 1d28d28a29
commit 7e658242e2
1 changed files with 123 additions and 119 deletions
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242
examples/starping_relay/starping_relay.pde
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@ -9,20 +9,27 @@
/**
* Example RF Radio Ping Star Group with Relay
*
* This sketch is a more complex example of using the RF24 library for Arduino.
* Deploy this on up to six nodes. Set one as the 'pong receiver' by tying the
* role_pin low, and the others will be 'ping transmit' units. The ping units
* unit will send out the value of millis() once a second. The pong unit will
* respond back with a copy of the value. Each ping unit can get that response
* back, and determine how long the whole cycle took.
* This sketch is a very complex example of using the RF24 library for Arduino.
* Deploy this on any number of nodes to create a basic mesh network. I have
* tested this on 6 nodes, but it should work on many more.
*
* This example introduces a new role, the 'relay', which can relay pings or
* pongs from one host to another. This is needed in larger meshes because
* each radio can only listen to 5-6 others.
* There are three different roles a node can be:
*
* This example requires a bit more complexity to determine which unit is which.
* The pong receiver is identified by having its role_pin tied to ground.
* The ping senders are further differentiated by a byte in eeprom.
* @li Leaf. Leaf nodes send a ping to the base unit, and wait for a pong in
* return
*
* @li Relay. Relay nodes do the same as a leaf node, AND they relay pings
* from leaf nodes toward the base, and relay pongs toward the leaves.
*
* @li Base. One node is the base station, which receives pings, and sends
* a pong back out.
*
* The address of each node is a number from 1 to n (the # of known nodes).
* It is set in EEPROM. To change a nodes address, send the character code
* for that address. e.g. send the character '5' to set address 5.
*
* The role is determined from the topology table. Leafs have no children.
* The base node has no parent. Relays have parents and children.
*/
#include <SPI.h>
@ -43,17 +50,11 @@ RF24 radio(8,9);
// Topology
//
// Radio pipe addresses for the nodes to communicate. Only ping nodes need
// dedicated pipes in this topology. Each ping node has a talking pipe
// that it will ping into, and a listening pipe that it will listen for
// the pong. The pong node listens on all the ping node talking pipes
// and sends the pong back on the sending node's specific listening pipe.
struct node_info
{
uint64_t talking_pipe; // Pipe used to talk to parent node
uint64_t listening_pipe; // Pipe used to listen to parent node
uint8_t parent_node; // Number of parent node
uint8_t parent_node; // Address of parent node
};
const node_info topology[] =
@ -106,10 +107,8 @@ uint8_t find_node( uint8_t current_node, uint8_t target_node )
// Role management
//
// Set up role. This sketch uses the same software for all the nodes
// in this system. Doing so greatly simplifies testing. The hardware itself specifies
// which node it is.
//
// This is done through the role_pin
// in this system. Doing so greatly simplifies testing. Role is
// determined by the topology table.
//
// The various roles supported by this sketch
@ -133,7 +132,7 @@ const uint8_t valid_eeprom_flag = 0xdf;
// What is our address (SRAM cache of the address from EEPROM)
// This is an index into the topology[] table above
uint8_t node_address = role_invalid;;
uint8_t node_address = -1;
//
// Payload
@ -171,15 +170,16 @@ const unsigned long pong_timeout = 250; // ms
const unsigned long ping_phase_shift = 100; // ms
const short timeout_shift_threshold = 3;
// Space to track the last packet we received from each node, useful
// for tracking lost packets
static uint16_t last_id_received[num_nodes];
void setup(void)
{
//
// Address
//
// Unless we find reasonable values in the EEPROM, these are the defaults
node_address = -1;
// Look for the token in EEPROM to indicate the following value is
// a validly set node address
if ( EEPROM.read(address_at_eeprom_location) == valid_eeprom_flag )
@ -244,7 +244,7 @@ void setup(void)
// Each leaf node has a talking pipe that it will ping into, and a listening
// pipe that it will listen for the pong. Relay nodes also do this.
if ( role == role_leaf || role == role_relay )
if ( role == role_leaf )
{
// Write on our talking pipe
radio.openWritingPipe(topology[node_address].talking_pipe);
@ -258,11 +258,14 @@ void setup(void)
// Remember to re-open the reading pipe whenever we start to listen again.
if ( role == role_relay )
{
// Write on our talking pipe
radio.openWritingPipe(topology[node_address].talking_pipe);
// Listen on our listening pipe
radio.openReadingPipe(0,topology[node_address].listening_pipe);
}
// The base and relay nodes listens on all their children node's talking pipes
// The base and relay nodes listen on all their children node's talking pipes
// and sends the pong back on the child node's specific listening pipe.
if ( role == role_base || role == role_relay )
{
@ -300,6 +303,10 @@ void setup(void)
}
}
void ping_if_ready(void);
void handle_pong(const payload_t& payload);
void check_pong_timeout(void);
void loop(void)
{
//
@ -308,39 +315,12 @@ void loop(void)
if ( role == role_leaf )
{
// Is it time to ping again?
unsigned long now = millis();
if ( now - last_ping_sent_at >= ping_delay )
{
last_ping_sent_at = now;
waiting_for_pong = true;
// First, stop listening so we can talk.
radio.stopListening();
// Take the time, and send it to the base. This will block until complete
payload_t ping(node_address,0,millis());
// Print details.
printf("%lu ",millis());
payload_printf(">PING",ping);
bool ok = radio.write( &ping, sizeof(payload_t) );
if (ok)
printf(" ok\n\r");
else
printf(" failed\n\r");
// Now, continue listening
radio.startListening();
}
ping_if_ready();
check_pong_timeout();
// Did we get a pong?
if ( radio.available() )
{
// Not waiting anymore, got one.
waiting_for_pong = false;
consecutive_timeouts = 0;
// Dump the payloads until we've gotten everything
payload_t payload;
boolean done = false;
@ -349,32 +329,9 @@ void loop(void)
// Fetch the payload, and see if this was the last one.
done = radio.read( &payload, sizeof(payload_t) );
// Print details.
printf("%lu ",millis());
payload_printf(">PONG",payload);
printf(" Round-trip delay: %lu\n\r",millis()-payload.time);
handle_pong(payload);
}
}
// Have we timed out waiting for our pong?
if ( waiting_for_pong && ( millis() - last_ping_sent_at > pong_timeout ) )
{
// Not waiting anymore, timed out.
waiting_for_pong = false;
// Timeouts usually happen because of collisions with other nodes
// getting a pong just as we are trying to get a ping. The best thing
// to do right now is offset our ping timing to search for a slot
// that's not occupied.
//
// Only do this after getting a few timeouts, so we aren't always skittishly
// moving around the cycle.
if ( ++consecutive_timeouts > timeout_shift_threshold )
last_ping_sent_at += ping_phase_shift;
// Print details
printf("TIMED OUT.\n\r");
}
}
//
@ -385,35 +342,8 @@ void loop(void)
{
#if 1
// Relay role is ALSO a ping sender!!
// Is it time to ping again?
unsigned long now = millis();
if ( now - last_ping_sent_at >= ping_delay )
{
last_ping_sent_at = now;
// First, stop listening so we can talk.
radio.stopListening();
// Write on our talking pipe. The relay has to do this every time, because
// we ALSO use pipe 0 as a listening pipe.
radio.openWritingPipe(topology[node_address].talking_pipe);
// Take the time, and send it to the base. This will block until complete
payload_t ping(node_address,0,millis());
printf("%lu ",millis());
payload_printf(">PING",ping);
bool ok = radio.write( &ping, sizeof(payload_t) );
if (ok)
printf(" ok.\n\r");
else
printf(" failed.\n\r");
// Now, continue listening
radio.openReadingPipe(0,topology[node_address].listening_pipe);
radio.startListening();
}
ping_if_ready();
check_pong_timeout();
#endif
// if there is data ready
uint8_t pipe_num;
@ -430,10 +360,7 @@ void loop(void)
// Is this for us?
if ( payload.to_node == node_address )
{
// Treat it as a PONG
printf("%lu ",millis());
payload_printf(">PONG",payload);
printf(" Round-trip delay: %lu\n\r",millis()-payload.time);
handle_pong(payload);
}
else
{
@ -472,14 +399,12 @@ void loop(void)
uint16_t pipe_id = out_pipe & 0xffff;
printf("OUT on pipe %04x %s.\n\r",pipe_id,ok?"ok":"failed");
}
}
// Now, resume listening so we catch the next packets.
radio.openReadingPipe(0,topology[node_address].listening_pipe);
radio.startListening();
}
}
}
}
//
// Base role. Receive each packet, dump it out, and send it back
@ -503,6 +428,17 @@ void loop(void)
printf("%lu ",millis());
payload_printf("PING",ping);
printf(" on pipe %u. ",pipe_num);
// Track the packets lost since we last heard from this node
// Packet loss is generally a sign of poor system health
uint16_t* last_id_ptr = &last_id_received[ping.from_node];
if ( *last_id_ptr && ping.id > *last_id_ptr )
{
uint16_t lost = ping.id - *last_id_ptr - 1;
if ( lost )
printf(" lost %u",lost);
}
*last_id_ptr = ping.id;
}
// First, stop listening so we can talk
@ -552,4 +488,72 @@ void loop(void)
}
}
}
void ping_if_ready(void)
{
// Is it time to ping again?
unsigned long now = millis();
if ( now - last_ping_sent_at >= ping_delay )
{
last_ping_sent_at = now;
waiting_for_pong = true;
// First, stop listening so we can talk.
radio.stopListening();
// Write on our talking pipe. The relay has to do this every time, because
// we ALSO use pipe 0 as a listening pipe.
radio.openWritingPipe(topology[node_address].talking_pipe);
// Take the time, and send it to the base. This will block until complete
payload_t ping(node_address,0,millis());
// Print details.
printf("%lu ",millis());
payload_printf(">PING",ping);
bool ok = radio.write( &ping, sizeof(payload_t) );
if (ok)
printf(" ok\n\r");
else
printf(" failed\n\r");
// Now, continue listening
radio.startListening();
}
}
void handle_pong(const payload_t& payload)
{
// Not waiting anymore, got one.
waiting_for_pong = false;
consecutive_timeouts = 0;
// Print details.
printf("%lu ",millis());
payload_printf(">PONG",payload);
printf(" Round-trip delay: %lu\n\r",millis()-payload.time);
}
void check_pong_timeout(void)
{
// Have we timed out waiting for our pong?
if ( waiting_for_pong && ( millis() - last_ping_sent_at > pong_timeout ) )
{
// Not waiting anymore, timed out.
waiting_for_pong = false;
// Timeouts usually happen because of collisions with other nodes
// getting a pong just as we are trying to send a ping. The best thing
// to do right now is offset our ping timing to search for a slot
// that's not occupied.
//
// Only do this after getting a few timeouts, so we aren't always skittishly
// moving around the cycle.
if ( ++consecutive_timeouts > timeout_shift_threshold )
last_ping_sent_at += ping_phase_shift;
// Print details
printf("TIMED OUT.\n\r");
}
}
// vim:ai:cin:sts=2 sw=2 ft=cpp