// Code Glimpse

Unleash The Power Of Iot With Weight Sensing Devices

Internet of Things (IoT) has become a highly influential field in the technological landscape due to its broad potential to bring automation and create smarter environments. Among various areas where IoT has touched upon, weight sensing devices are an exciting field. Today, we will dive into one such weight sensing application - designing a smart inventory system using IoT and load cell.

What are Load Cells?

A Load Cell is a type of transducer that transforms force into an electrical signal. In the context of IoT, these load cells or weight sensors can connect to various other devices and communicate the detected weight over the Internet.

Load Cell Modules

One popular module available in the market is the HX711, an amplifying circuit for load cells. It provides us with the raw data from the load cell. Here is an example of how you might connect an Arduino to a load cell through an HX711 module:

#include "HX711.h"

#define DOUT  3
#define CLK  2

HX711 scale(DOUT, CLK);

long readValue;

void setup() {
  Serial.begin(9600);
  scale.set_scale(2280.f); 
  scale.tare(); 
}

void loop() {
  readValue = scale.get_units(), 1;
  Serial.print("Reading: ");
  Serial.println(readValue);
}

Now, this was the hardware side to read values from a load cell, but the combination of this data with IoT makes it powerful.

Integrating with IoT Platform

As an example, let's integrate the weight sensing device with an IoT platform like Thingspeak to display the weight data.

#include <SPI.h>
#include <Ethernet.h>
#include "HX711.h"

byte mac[] = { 
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED 
};
IPAddress ip(192,168,1,177);
EthernetClient client;

char server[] = "api.thingspeak.com";
String writeAPIKey = "Your-Thingspeak-Write-API-Key";

void setup() {
  Ethernet.begin(mac, ip);
  delay(1000);
  
  setupScale();

  String data = "field1=" + String(scale.get_units(), 1);
  updateThingSpeak(data);
}

void loop() {}

void setupScale() {
  // similar to the previous example
}

void updateThingSpeak(String tsData) {
  if (client.connect(server,80)) {
    client.println("POST /update HTTP/1.1");
    client.println("Host: api.thingspeak.com");
    client.println("Connection: close");
    client.println("X-THINGSPEAKAPIKEY: "+writeAPIKey);
    client.println("Content-Type: application/x-www-form-urlencoded");
    client.println("Content-Length: " + String(tsData.length()));
    client.println();
    client.println(tsData);
  } 
  else {
    client.stop();
  }
}

This script would send the weight data to Thingspeak, which can then be used for other complex applications!

Conclusion

As seen from our load cell example, IoT has the power to create smarter and efficient systems. There are many applications where you could apply it like inventory management, waste management etc. Let your creativity shine!

References