echo IP > leds

ip_leds.c

/*
 * ip_leds
 *
 * Copyright (c) 2016 Dries007
 * License: MIT
 *
 * Display some random effects until an IP is got,
 * then show the IP in binary on the leds.
 *
 * Library:
 *      wiringPi
 *
 * Pinout:
 *      LEDS 0->7 are on wiringPi pins 0-7 EXCEPT led 6, its on pin 15.
 *
 *
 * Compile with gnu11 & lib wiringPi:
 *      gcc -std=gnu11 -Wall -0 pi_leds ip_leds.c -lwiringPi
 */

#include <stdio.h>
#include <wiringPi.h>
#include <signal.h>

#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define I_FACE "wlan0"
#define TIME_BINARY 5000
#define TIME_POSITION 1000


#define EFFECTS (sizeof(effects) / sizeof(fn_effect_t))

typedef void (*fn_effect_t)(int delay_ms, uint8_t invert);
fn_effect_t effects[];

void writeByteFix(uint8_t data, int wait_ms);
void blink(uint8_t data, int time_on, int time_off, int count);
void rnd_effect();
uint32_t getIpv4(const char *name);

void intHandler(int dummy)
{
    writeByteFix(0x00, 0);
    exit(0);
}

int main(void)
{
    wiringPiSetup();
    for (int i = 0; i < 8; i++) pinMode(i != 6 ? i : 15, OUTPUT);
    writeByteFix(0x00, 0);

    signal(SIGINT, intHandler);

    while (1)
    {
        rnd_effect();

        uint32_t ip = getIpv4(I_FACE);

        if (ip == 0 || ip == -1)
        {
            printf("No ip.\n");
            continue;
        }

        printf("IP: %d.%d.%d.%d\n", 0xFF & (ip >> 24), 0xFF & (ip >> 16), 0xFF & (ip >> 8), 0xFF & (ip >> 0));

        blink(1 << 3, 1, 2, TIME_POSITION); writeByteFix(0xFF & (ip >> 24), TIME_BINARY);
        blink(1 << 2, 1, 2, TIME_POSITION); writeByteFix(0xFF & (ip >> 16), TIME_BINARY);
        blink(1 << 1, 1, 2, TIME_POSITION); writeByteFix(0xFF & (ip >> 8), TIME_BINARY);
        blink(1 << 0, 1, 2, TIME_POSITION); writeByteFix(0xFF & (ip >> 0), TIME_BINARY);

    }
}

// Implementations

void writeByteFix(uint8_t data, int wait_ms)
{
    // Really? What is this madness
    digitalWriteByte(data & 0b10111111);
    digitalWrite(15, data & 0b01000000);
    delay(wait_ms);
}

uint32_t getIpv4(const char *name)
{
    struct ifaddrs *ifaddr;
    uint32_t out = 0;

    if (getifaddrs(&ifaddr) == -1) return -1;
    for (struct ifaddrs * ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next)
    {
        if (ifa->ifa_addr == NULL || ifa->ifa_addr->sa_family != AF_INET) continue;
        if (strcmp(ifa->ifa_name, "wlan0") == 0)
        {
            out = ntohl(((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr);
            break;
        }
    }

    freeifaddrs(ifaddr);
    return out;
}

void blink(uint8_t data, int time_on, int time_off, int count)
{
    while (--count > 0)
    {
        writeByteFix(data, time_on);
        writeByteFix(0x00, time_off);
    }
}

void effect_shift_l(int delay_ms, uint8_t invert)
{
    for (int i = 0; i < 8; i++)
        writeByteFix(invert ? ~(1 << i) : 1 << i, delay_ms);
}

void effect_shift_r(int delay_ms, uint8_t invert)
{
    for (int i = 7; i >= 0; i--)
        writeByteFix(invert ? ~(1 << i) : 1 << i, delay_ms);
}

void effect_knight_rider(int delay_ms, uint8_t invert)
{
    for (int i = 0; i < 6; i++)
        writeByteFix(invert ? ~(0b00000111 << i) : 0b00000111 << i, delay_ms);
    for (int i = 5; i >= 0; i--)
        writeByteFix(invert ? ~(0b00000111 << i) : 0b00000111 << i, delay_ms);
}

void effect_fill(int delay_ms, uint8_t invert)
{
    for (int i = 0; i < 0x100; i = i * 2 + 1)
        writeByteFix(invert ? ~i : i, delay_ms);
}

void effect_empty(int delay_ms, uint8_t invert)
{
    for (int i = 0xFF; i > 0; i >>= 1)
        writeByteFix(invert ? ~i : i, delay_ms);
}

void effect_toggle(int delay_ms, uint8_t invert)
{
    writeByteFix(invert ? ~0xAA : 0xAA, delay_ms);
    writeByteFix(invert ? ~0x55 : 0x55, delay_ms);
}

fn_effect_t effects[] = {&effect_shift_l, &effect_shift_r, &effect_knight_rider, &effect_fill, &effect_empty, &effect_toggle};

void rnd_effect(void)
{
    int effect_nr = rand() % EFFECTS;
    uint8_t invert = rand() % 2;
    for (int i = 2 + (rand() % 5); i >= 0; i--) effects[effect_nr](50, invert);
    writeByteFix(0x00, 500);
}