Control a garage door with a Raspberry Pi and Echo

garageDoor.c

// A script that runs a raspberry pi to receive commands from an echo
// and control a garage door opener wired to the GPIO

// To set up the Echo, follow this guide: 
// https://read.acloud.guru/how-to-build-your-own-alexa-voice-activated-iot-smart-lamp-for-less-than-35-9820ccd07516

// To compile this script, use the Makefile in the subscribe_publish_sample of the AWS IoT Device SDK. You'll 
// need to link in the wiringPi library.

// If you are having policy issues, you can create a super-permissive policy that will let your device do anything:
// 
// {
//   "Version": "2020-6-20",
//   "Statement": [
//     {
//       "Effect": "Allow",
//       "Action": "iot:*",
//       "Resource": "arn:aws:iot:<your-region>:<your-id>:*"
//     }
//   ]
// }

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
#include <limits.h>
#include <string.h>
#include <wiringPi.h>

#include "aws_iot_config.h"
#include "aws_iot_log.h"
#include "aws_iot_version.h"
#include "aws_iot_mqtt_client_interface.h"

#define HOST_ADDRESS_SIZE 255
/**
 * @brief Default cert location
 */
char certDirectory[PATH_MAX + 1] = "certs";

/**
 * @brief Default MQTT HOST URL is pulled from the aws_iot_config.h
 */
char HostAddress[HOST_ADDRESS_SIZE] = AWS_IOT_MQTT_HOST;

/**
 * @brief Default MQTT port is pulled from the aws_iot_config.h
 */
uint32_t port = AWS_IOT_MQTT_PORT;

void iot_subscribe_callback_handler(AWS_IoT_Client *pClient, char *topicName, uint16_t topicNameLen,
									IoT_Publish_Message_Params *params, void *pData) {
	IOT_UNUSED(pData);
	IOT_UNUSED(pClient);
	IOT_INFO("Subscribe callback");
	IOT_INFO("%.*s\t%.*s", topicNameLen, topicName, (int) params->payloadLen, (char *) params->payload);

	digitalWrite(25, HIGH);
	sleep(5);
	digitalWrite(25, LOW);
}

void disconnectCallbackHandler(AWS_IoT_Client *pClient, void *data) {
	IOT_WARN("MQTT Disconnect");
	IoT_Error_t rc = FAILURE;

	if(NULL == pClient) {
		return;
	}

	IOT_UNUSED(data);

	if(aws_iot_is_autoreconnect_enabled(pClient)) {
		IOT_INFO("Auto Reconnect is enabled, Reconnecting attempt will start now");
	} else {
		IOT_WARN("Auto Reconnect not enabled. Starting manual reconnect...");
		rc = aws_iot_mqtt_attempt_reconnect(pClient);
		if(NETWORK_RECONNECTED == rc) {
			IOT_WARN("Manual Reconnect Successful");
		} else {
			IOT_WARN("Manual Reconnect Failed - %d", rc);
		}
	}
}

int main(int argc, char **argv) {
	bool infinitePublishFlag = true;

	char rootCA[PATH_MAX + 1];
	char clientCRT[PATH_MAX + 1];
	char clientKey[PATH_MAX + 1];
	char CurrentWD[PATH_MAX + 1];
	char cPayload[100];

	int32_t i = 0;

	IoT_Error_t rc = FAILURE;

	AWS_IoT_Client client;
	IoT_Client_Init_Params mqttInitParams = iotClientInitParamsDefault;
	IoT_Client_Connect_Params connectParams = iotClientConnectParamsDefault;

	IOT_INFO("\nAWS IoT SDK Version %d.%d.%d-%s\n", VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH, VERSION_TAG);

	getcwd(CurrentWD, sizeof(CurrentWD));
	snprintf(rootCA, PATH_MAX + 1, "%s/%s/%s", CurrentWD, certDirectory, AWS_IOT_ROOT_CA_FILENAME);
	snprintf(clientCRT, PATH_MAX + 1, "%s/%s/%s", CurrentWD, certDirectory, AWS_IOT_CERTIFICATE_FILENAME);
	snprintf(clientKey, PATH_MAX + 1, "%s/%s/%s", CurrentWD, certDirectory, AWS_IOT_PRIVATE_KEY_FILENAME);

	IOT_DEBUG("rootCA %s", rootCA);
	IOT_DEBUG("clientCRT %s", clientCRT);
	IOT_DEBUG("clientKey %s", clientKey);
	mqttInitParams.enableAutoReconnect = false; // We enable this later below
	mqttInitParams.pHostURL = HostAddress;
	mqttInitParams.port = port;
	mqttInitParams.pRootCALocation = rootCA;
	mqttInitParams.pDeviceCertLocation = clientCRT;
	mqttInitParams.pDevicePrivateKeyLocation = clientKey;
	mqttInitParams.mqttCommandTimeout_ms = 20000;
	mqttInitParams.tlsHandshakeTimeout_ms = 5000;
	mqttInitParams.isSSLHostnameVerify = true;
	mqttInitParams.disconnectHandler = disconnectCallbackHandler;
	mqttInitParams.disconnectHandlerData = NULL;

	rc = aws_iot_mqtt_init(&client, &mqttInitParams);
	if(SUCCESS != rc) {
		IOT_ERROR("aws_iot_mqtt_init returned error : %d ", rc);
		return rc;
	}

	connectParams.keepAliveIntervalInSec = 600;
	connectParams.isCleanSession = true;
	connectParams.MQTTVersion = MQTT_3_1_1;
	connectParams.pClientID = AWS_IOT_MQTT_CLIENT_ID;
	connectParams.clientIDLen = (uint16_t) strlen(AWS_IOT_MQTT_CLIENT_ID);
	connectParams.isWillMsgPresent = false;

	IOT_INFO("Configuring the circuit ...");
	wiringPiSetup();
  pinMode(25, OUTPUT);

	IOT_INFO("Connecting...");
	rc = aws_iot_mqtt_connect(&client, &connectParams);
	if(SUCCESS != rc) {
		IOT_ERROR("Error(%d) connecting to %s:%d", rc, mqttInitParams.pHostURL, mqttInitParams.port);
		return rc;
	}
	/*
	 * Enable Auto Reconnect functionality. Minimum and Maximum time of Exponential backoff are set in aws_iot_config.h
	 *  #AWS_IOT_MQTT_MIN_RECONNECT_WAIT_INTERVAL
	 *  #AWS_IOT_MQTT_MAX_RECONNECT_WAIT_INTERVAL
	 */
	rc = aws_iot_mqtt_autoreconnect_set_status(&client, true);

	if(SUCCESS != rc) {
		IOT_ERROR("Unable to set Auto Reconnect to true - %d", rc);
		return rc;
	}

	IOT_INFO("Subscribing to 'garageDoor' ...");
	rc = aws_iot_mqtt_subscribe(&client, "garageDoor/+", 12, QOS0, iot_subscribe_callback_handler, NULL);

	if(SUCCESS != rc) {
		IOT_ERROR("Error subscribing : %d ", rc);
		return rc; 
	}

	while((NETWORK_ATTEMPTING_RECONNECT == rc || NETWORK_RECONNECTED == rc || SUCCESS == rc)) {

		// Max time the yield function will wait for read messages
		rc = aws_iot_mqtt_yield(&client, 100);
		if(NETWORK_ATTEMPTING_RECONNECT == rc) {
			// If the client is attempting to reconnect we will skip the rest of the loop.
			continue;
		}
		sleep(1);
	}

	// Wait for all the messages to be received
	aws_iot_mqtt_yield(&client, 100);

	if(SUCCESS != rc) {
		IOT_ERROR("An error occurred in the loop.\n");
	} else {
		IOT_INFO("Publish done\n");
	}

	return rc;
}