How to use SCALAE - IOT

7 min

SCALAE - IOT

This product has been superseded by Widg-X. Please see the following topic How to use Widg-X

Introduction

SCALAE WIFI Switch or SCALAE-IOT is one of our versatile products that can be programmed to accomplish different tasks as needed. The hardware is arranged for a monitoring application with the ability to actuate autonomously and then provide reporting and feedback along with the option for remote control and monitoring. The product falls into our AUTOMATE | CONNECT | CONTROL philosophy.

This application will introduce the product's features and then step you through a basic application of measuring the analog value of a moisture sensor.

Features

The following features give the SCALAE-IOT some punch when used in a field application and enable it to perform a number of tasks effectively.

Specifications	WiFi Switch
Device	PIC Microcontroller: PIC18F2xKxx - SOIC family device
USB Connectivity	YES - for system configuration local data logging.
Device Programming	ICSP \| USART Bootloader
Power Supply	Onboard PSU, optimized for low-power operation.
IO	Reset Button, Opto Isolated inputs, Relay Output
Temperature Sensors	Dallas 1-Wire (Ruggardised), LM35, DHT-11
Communication	WIFI - ESP8266*, optional module
USB UART	CH340G

*These sensors or modules are recommended or have been tested with the SCALAE-IOT.

Overview

This project example will demonstrate integrating a soil moisture sensor. This will include how to connect the sensor and then read and interpret the reading.

Implementation

To get started, your shopping list is the following:

SCALAE IoT

Soil Moisture Sensor (Seed Studio)

Jumpers

Power Supply

Dry Soil + jug of water to

Code

The code has been written using MikroC, which is a C-centric compiler. The compiler is a very useful coding environment as it also includes many integrated libraries.

The code does the following:

Configure the hardware

Read the sensor

Process the reading

Report the value

/*
  SCALAE IoT - Dev Version
  October 2024
  Device: PIC18F25K22
*/


//------------------------------------------------------------------Declarations
#define AN 1

char *ver ="Node_V_Dev";
char uart_rd;
char *SoilMoisValu ="0000";
char *SoilMoisTest="0000";
unsigned short ADC_channel;
unsigned temp;
int i;

//---------------------------------------------------------------------Functions
void SetupSystem(void);
void CR();
char *SoilMoisture(unsigned short channel);
//--------------------------------------------------------------------------Code

void CR(){

  UART1_Write(10);
  UART1_Write(13);
  Delay_ms(10);
}

char *SoilMoisture(unsigned short channel){

 char *_temp = "0000";
 unsigned int _adc_value;

 _adc_value = ADC_Read(channel);
 delay_ms(10);

 _temp[0] = _adc_value/1000 + 48; // Add 48 to get the ASCII character value
 _temp[1] = (_adc_value/100)%10 + 48;
 _temp[2] = (_adc_value/10)%10 + 48;
 _temp[3] = _adc_value%10 + 48;

 return _temp;

}

void SetupSystem(void){
  
  /*Analog Configuration*/
  ANSELA = 0b00000010;                     // Configure AN pins as digital
  ANSELB = 0;
  ANSELC = 0;
  
  /*Ports Configuration*/
  TRISA = 0b00000010;;
  TRISB = 0;
  TRISC = 0;
  
  C1ON_bit = 0;               // Disable comparators
  C2ON_bit = 0;

  /*UART Communications*/
  UART1_Init(9600);             // Initialize UART module at 9600 bps
  Delay_ms(100);                  // Wait for UART module to stabilize
  
  UART1_Write_Text(ver);
  CR();
}

void main() {

     SetupSystem();

     while(1){
     
              if (UART1_Data_Ready()) {     // If data is received,
              
              uart_rd = UART1_Read();       // read the received data,
              
              switch (uart_rd){
              
                        case'a' : UART1_Write('A');break;
                        case'v' : UART1_Write_Text(ver);break;
                        default:  UART1_Write(uart_rd);         // and send data via UART
                        }
              }
              
              SoilMoisValu = SoilMoisture(AN);
              Delay_ms(10);
              
              Uart1_Write_Text(SoilMoisValu);
              Delay_ms(1000);
              CR();              
              
     }
}

What the code does

The code accomplishes key tasks that are required to set up the hardware, then for the module to repeatedly and reliably perform the task of processing and reporting the value.

The function SetupSystem() is tasked with configuring the MCU. For this application, the device is setup mainly for "safe" operation to prevent any spurious actions taking place. For this reason, all I/O are set to inputs and this prevents the relay from actuating for example.

This then brings us back to the void main() that calls the SetupSystem() function and then once in the while(1) loop, then calls, at this point the main working function.

The SoilMoisture() function takes in the parameter for the analog channel that would be used. This is to accommodate any future changes where an alternative channel may be used.

The MikroC provides a library for reading the Analog inputs, with the only input parameter required being the channel. This is passed in, and the value is returned.

Once the A2D module has performed the calculation, you have a large number that needs to be processed firstly a value that can be reported using an LCD or USART and secondly, a format that can be interpreted and used.

This is performed within the function, converting it to a *char which can be exported using the USART. You can also a LCD display as the value is compatible type.

To view the value being reported, you can use the COMs terminal available from within MikroC. It is located here Tools > Usart Terminal.

As noted in the values reported, a high value indicates drier soil and a lower value more moist soil.

What is Next?

In the next installment, we will consider how to use the value that was read and what actions that can be take.