Alsufiyan • Posted by SHANGUGAPRIYA G

Published May 16, 2022

Reed Switch With monoZero

Reed switch is a magnetic type, if the switch enters a magnetic field, the contact feathers will closed, and it provides electrical signals.

IntermediateProtipOver 1 day96

Things used in this project

Hardware components

Reed Switch, SPST-NO

Resistor 10k ohm

Male-Header 5 Position- 1 Row- Long (0.1")

Female/Female Jumper Wires

Male/Male Jumper Wires

General Purpose Printed Circuit Board

monoZ™ monoZero 1WG

monoZ™ monoZero Grove

Software apps and online services

STMicroelectronics STM32CUBEPROG

monoZ™ monoZ SDK

Story

monoZero Cellular IoT solution is the one of the best alternatives to the regular restricted areas entry management system. The monoZero hardware has a built-in 1WG module that supports LwM2M protocol with NIDD (Non-IP Data Delivery). Users need to insert an IoT SIM to the monoZero to make 1WG active and do cloud setup to receive and see the data. It has an SDK that makes programming simple using its own APIs, for example APIs that can send processed data as payload to the cloud.

Reed switch with monoZero is one such example where users can easily plug a magnetic reed switch to the monoZero Grove board. Add simple codes to read the switch status and add the monoZ SDK APIs to send the reed switch status as payload to the cloud.

Reed switch is also called an inductive-magnetic sensor.
Reed switch is a magnetic type switch, when the switch enters a magnetic field, the contact feathers will close and it provides electrical signals.
Reed switch is used in many of the real-life applications such as magnetic door switch, laptops, smartphones etc.
In this tutorial, we will learn about Reed Switch and guide you, how to Interface a Reed Switch with monoZero _1WG board.

HARDWARE :

1 ) Connect the monoZero Grove board on the MonoZero 1WG V3 board

2) Connect the Grove Switch on the monoZero Grove board as per the schematic given.

Things You Need :

1 / 3 • monoZero 1WG V3

Working of Reed switch:

Connect the Reed switch to the Grove board, upload the program using STM cube IDE and run the code.
When the Reed switch enters a magnetic field, the contact feathers become closed, monoZero 1WG gives 31 as payload to the server.
When the Reed switch is removed from a magnetic field, the contact feathers become open, monoZero 1WG gives 30 as payload to the server.

Result:

The server output:

Server output

Sample Dashboard Output :

Sample Email Alert Notification:

Email Alert Notification

Application:

Monitoring Entry in Restricted Areas with monoZero Cellular IoT solution :

This real time application gets the count of people entering inside a restricted area/building/exhibition hall for a particular period of time using monoZero Cellular IoT solution. We need a magnetic switch connected to monoZero 1WG. This setup can be installed at the entry of this restricted area/building/exhibition hall. Adding some code to get the count of the visitors who entered this place for a particular period of time and using the Monoz SDK APIs, monoZero sends this count as payload to the cloud. By getting this count from the cloud, the machine can limit the entry of the visitors entering into this area or to block the entrance for a particular period of time.

Home/commercial security system with monoZero Cellular IoT solution :

One of the best alternatives for the existing expensive security systems is this monoZero Cellular IoT solution. Using this monoZero Cellular IoT, monitoring of the home/commercial security system can be made more compact and efficient. monoZero board contains a built-in 1WG module and makes the system compact. For executing this application, users just need to plug a reed switch (or any similar part) to monoZero. This setup is to be installed at doors/windows that need to be monitored. Add some code to read the reed switch status and use the Monoz SDK APIs to send the reed switch status as payload to the cloud. Now monoZero Cellular IoT system can monitor the status of the doors/windows. When there is absence of people in the building and if someone tries to open the doors/windows, then the monoZero gets the status of reed switch immediately and sends this alert notification as payload to the cloud. Owner gets alert notification and can take necessary action.

Code

/*
 * MZ_Board_Reed_Switch.c
 *
 *  Created on: Mar 15, 2022
 *  Author: Alsufiyan
 */

/* Include Header Files - START */
#include "MZ_Board_Reed_Switch.h"
#include "MZ_sys_cmsis_os2.h"
#include "MZ_error_handler.h"
#include "MZ_timer.h"
#include "MZ_print.h"
#include "MZ_Lwm2m_public.h"
#include "MZ_type_converter.h"
#include "MZ_Modem_public.h"
#include "MZ_uart.h"
#include "MZ_main.h"
#include "stdlib.h"
#include "main.h"
/* Include Header Files - END */

/* Define some common use MACRO - START */
//#define REED_SWITCH_STATUS			//Macro to enable read and send Reed Switch Status
#define PUSH_BUTTON_STATUS			//Macro to enable read and send Push Button Status

#define SERVER_REG_NEED_SET						(0)
#define SERVER_REG_NEED_CLEAR						(1)
#define EXTI_CB_FLAG_CLEAR						(0)
#define EXTI_CB_FLAG_SET						(1)
#define OBSERVE_COMPLETE_SET						(1)
#define OBSERVE_COMPLETE_CLEAR					(0)
#define TIME_180SEC							(pdMS_TO_TICKS(180000))
#define TIMER_ID_CLEAR							(0)
/* Define some common use MACRO - END */

/* Thread related MACRO and variables - START */
#define SWITCH_APP_STACK_SIZE		(1024)  						
static mz_thread_t 			switch_thread_id = NULL;				
static StaticTask_t 			switch_cb_mem;						
static StackType_t 			switch_stack[SWITCH_APP_STACK_SIZE];			
/* Thread related MACRO and variables - END */

/* Timer related MACRO and variables - START */
#define LWM2M_SERVER_MONITORING_TIME		(TIME_180SEC)
static size_t lwm2m_server_monitoring_timer_id = TIMER_ID_CLEAR;				
/* Timer related MACRO and variables - END */

/* Reed switch related MACRO and variables - START */
//#define REED_SWITCH								REED_SW_Pin
#define PUSH_BUTTON								PB_Pin
static char external_interrupt_cb_flag  = EXTI_CB_FLAG_CLEAR;
static uint16_t exti_pin=0;
static uint8_t reed_switch_status=0;
static uint8_t push_button_status=0;
static uint8_t locstr[50]={0};
/* Reed switch related MACRO and variables - END */

/* LWM2M related MACRO and variables - START */
static char lwm2m_server_rereg_flag = SERVER_REG_NEED_CLEAR;				
static char observe_receive_flag = OBSERVE_COMPLETE_CLEAR;				
static char payload_string[11] = "";							
static char payload_string_1[11] = "";						
/* LWM2M related MACRO and variables - END */

extern void mz_reboot_sequence(void * arg);

/* static function prototypes - START */
static void lwm2m_server_monitoring_timer_cb(TimerHandle_t xTimer);
static void switch_read_timer_cb(TimerHandle_t xTimer);
static void lwm2m_server_reregistration(void);
static void create_lwm2m_payload_reed_switch(void);
static void send_reed_payload_to_server(void);
static void create_lwm2m_payload_pb(void);
static void send_pb_payload_to_server(void);
static void switch_app_thread(void * arg);
static void process_switch_status();
static uint32_t int32_to_string_decimal(uint8_t *dststr,uint32_t num);
/* static function prototypes - END */

/*============================================================================*/
/*           Monoz switch status and data send to Lwm2m server - START         */
/*============================================================================*/

/* EXTI line detection callback -START.  */
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
	external_interrupt_cb_flag  = EXTI_CB_FLAG_SET;
	exti_pin = GPIO_Pin;
}
/*  EXTI line detection callback - END */

/*   process_switch_status -START.  */
static void process_switch_status(){
#ifdef REED_SWITCH_STATUS
	if(HAL_GPIO_ReadPin(GPIOD, REED_SWITCH)){
		reed_switch_status=1;
		mz_puts("Reed Switch Status: open\r\n");
	}else{
		reed_switch_status=0;
		mz_puts("Reed Switch Status: closed\r\n");
	}
#endif
#ifdef PUSH_BUTTON_STATUS
	if(HAL_GPIO_ReadPin(GPIOD, PUSH_BUTTON)){
		push_button_status=1;
		mz_puts("Push Button Status: open\r\n");
	}else{
		push_button_status=0;
		mz_puts("Push Button Status: closed\r\n");
	}
#endif
}
/*  process_switch_status - END */

/* LWM2M server registration monitoring timer callback - START
 */
static void lwm2m_server_monitoring_timer_cb(TimerHandle_t xTimer)
{
	/* Check if observe has not started */
	if(OBSERVE_COMPLETE_CLEAR == observe_receive_flag)
	{
		/* Then set the server re-registration flag */
		lwm2m_server_rereg_flag = SERVER_REG_NEED_SET;
	}
}
/* LWM2M server registration monitoring timer callback - END */

/* LWM2M server re-registration API - START
 
 */
static void lwm2m_server_reregistration(void)
{
	/* Clear previous observe receive flag */
	observe_receive_flag = OBSERVE_COMPLETE_CLEAR;

	/* Starting the Lwm2m server monitoring one time timer */
	if(MZ_OK != mz_tm_start(lwm2m_server_monitoring_timer_id))
	{
		mz_puts("Server monitoring timer creation failed\r\n");
	}

	/* Initiate the server re-registration */

	if(MZ_OK == MZ_modem_config_set(mz_reboot_sequence))
	{
		/* print the success in the CLI */
		mz_puts("Server re-reg sequence started\r\n");
	}
	else
	{
		/* print the fail - It will be again tried on next timer expire */
		mz_puts("Server re-reg sequence failed\r\n");
	}
}
/* LWM2M server re-registration API - END */

/* LWM2M Create payload API - START */
static void create_lwm2m_payload_reed_switch(void)
{
	/*
	 * As all the payload is just number, this is a optimized implementation
	 * of converting the final value to ASCII HEX string
	 */
	payload_string[0] = '\"';
	payload_string[1] = '3';
	payload_string[2] = '0' + reed_switch_status;
	payload_string[3] = '\"';
	payload_string[4] = '\0';
}
/* LWM2M Create payload API - END */

/*  LWM2M send payload API - START */
static void send_reed_payload_to_server(void)
{
	/* Set the Object 19/0/0 Data and send the Notify request to MonoZ_Lib */
	mz_error_t status = mz_set_and_notify_Ob19_0_0(payload_string);

	/* Check the status of the request */
	if(MZ_OK == status)
	{
		/* print success on CLI */
		mz_puts("Notify send to MonoZ_Lib\r\n");
	}
	else
	{
		/* print of error string on CLI */
		mz_puts(mz_error_to_str(status));
	}
}

/* LWM2M Create payload API - START */
static void create_lwm2m_payload_pb(void)
{
	/*
	 * As all the payload is just number, this is a optimized implementation
	 * of converting the final value to ASCII HEX string
	 */
	payload_string_1[0] = '\"';
	payload_string_1[1] = '3';
	payload_string_1[2] = '0' + push_button_status;
	payload_string_1[3] = '\"';
	payload_string_1[4] = '\0';
}
/* LWM2M Create payload API - END */

/*  LWM2M send payload API - START */
static void send_pb_payload_to_server(void)
{
	/* Set the Object 19/0/0 Data and send the Notify request to MonoZ_Lib */
	mz_error_t status = mz_set_and_notify_Ob19_0_0(payload_string_1);

	
	if(MZ_OK == status)
	{
		/* print success on CLI */
		mz_puts("Notify send to MonoZ_Lib\r\n");
	}
	else
	{
	
		mz_puts(mz_error_to_str(status));
	}
}

/* LWM2M send payload API - END */
/*  Switch main Application thread. - START */
static void switch_app_thread(void * arg)
{
	(void)arg;

	lwm2m_server_monitoring_timer_id =
			mz_tm_create_one("Server monitoring timer",
							LWM2M_SERVER_MONITORING_TIME,
							lwm2m_server_monitoring_timer_cb);
	/* Starting the Lwm2m server monitoring timer.	 */
	(void)mz_tm_start(lwm2m_server_monitoring_timer_id);

	/* Print on the console about timer start */
	mz_puts("Server monitoring timer started\r\n");

	while(1)
	{
	
		if(SERVER_REG_NEED_SET == lwm2m_server_rereg_flag)
		{
			/* clear the server re-registration flag */
			lwm2m_server_rereg_flag = SERVER_REG_NEED_CLEAR;

			/* Perform lwm2m server re-registration */
			lwm2m_server_reregistration();
		}
		if(EXTI_CB_FLAG_SET == external_interrupt_cb_flag){
			// process switch status
			process_switch_status();
			#ifdef REED_SWITCH_STATUS
			// Create the lwm2m payload for reed switch
			create_lwm2m_payload_reed_switch();
			// Send the reed switch payload to server
			send_reed_payload_to_server();
			#endif

			#ifdef PUSH_BUTTON_STATUS
			// Create the lwm2m payload for push button
			create_lwm2m_payload_pb();
			// Send the push button payload to server
			send_pb_payload_to_server();
			#endif
			/* clear the flag after processing */
			external_interrupt_cb_flag  = EXTI_CB_FLAG_CLEAR;
		}



		/* Put a delay to avoid blocking on this thread */
		HAL_Delay(10);


	}//End of while(1) - Do not place any code after this.

}
/* Switch main Application thread. - END */

/*
Switch Application initialization API. - START
 
 */
mz_error_t switch_app_init(void)
{
	uint8_t _ret= MZ_OK;

	/* Clear locstr of reed switch */
	memset(&locstr,0,sizeof(locstr));

	/* Create the Reed application thread */
	if(!mz_thread_create(	&switch_thread_id,
							"switch_app_scheduler",
							switch_app_thread,
							NULL,
							osPriorityNormal,
							switch_stack,
							SWITCH_APP_STACK_SIZE,
							&switch_cb_mem,
							sizeof(switch_cb_mem)))
	{
		_ret = MZ_THREAD_CREATE_FAIL;
	}

	_ret = mz_set_value_Ob19_0_0("\"30303030\"");
	if(MZ_OK != _ret) goto clean;
	_ret = mz_set_value_Ob19_1_0("\"30303030\"");
	if(MZ_OK != _ret) goto clean;

	clean :
	return _ret;
}
/* Switch Application initialization API. - END */

/*============================================================================*/
/*           Monoz Reed Switch Count and send to Lwm2m server - END           */
/*============================================================================*/

/*============================================================================*/
/*        Monoz Reed Switch Count - LWM2M event related code - START          */
/*============================================================================*/
/*
 * LWM2M user defined callback function. - START
 */
void lwm2m_event_process(void * event)
{
	st_lw_event * e = event;


	switch(e->lw_event)
	{
	
		case LW_EV_OBSERVE:
			
			mz_puts("Observe received\r\n");
		
			if(e->lw_Obj_id == 19 && e->lw_Obj_Ins_id == 0 && e->lw_Res_id == 0)
			{
				/* Set the observed received flag */
				observe_receive_flag = OBSERVE_COMPLETE_SET;
			}
		break;
		case LW_EV_CLIENT_NOTIFY_SEND:
			
			mz_puts("Notify send to server\r\n");
		break;
		case LW_EV_CLIENT_NOTIFY_SEND_ACK:
	
			mz_puts("Notify send acknowledge\r\n");
		break;
		case LW_EV_NOTIFY_FAIL:

			mz_puts("Notify send failed\r\n");
		break;
		case LW_EV_CLIENT_OFF:
	
			lwm2m_server_rereg_flag = SERVER_REG_NEED_SET;
		break;

#if 0
		
		case LW_EV_WRITE_DATA:
			/* Do something */
			;
		break;
		case LW_EV_EXECUTE:
			/* Do something */
			;
		break;
		case LW_EV_READ:
			/* Do something */
			;
		break;
		case LW_EV_OBSERVE_CANCEL:
			/* Do something */
			;
		break;
#endif

		default:
		break;
	}
}
/*============================================================================*/
/*        Monoz Reed Switch Count - LWM2M event related code - END            */
/*============================================================================*/

/*============================================================================*/
/* 			     Utils Functions - START                           */
/*============================================================================*/
static uint32_t int32_to_string_decimal(uint8_t *dststr,uint32_t num){
	uint32_t val=0;
	uint8_t mod=0;
	uint8_t i=0;
	uint8_t j=0;
	uint8_t len=0;
	uint8_t lbuf[15];
	val = num;
	mod = val%10;
	while(val > 0){
		mod = val%10;
		lbuf[i] = mod + 48;
		val = val/10;
		i++;
	}
	len=i;
	for(j=0;j<len;j++){
		i--;
		dststr[j]=lbuf[i];
	}
	j++;
	dststr[j]='\0';
//	dststr[j]='\n';
}
/*============================================================================*/
/* 			     Utils Functions - END                             */
/*============================================================================*/

Credits

Alsufiyan

Posted by

SHANGUGAPRIYA G

Reed Switch With monoZero