Hacking STEMJen Fox
Published

Hacking STEM Electromagnetic Sensor

A simple electromagnetic sensor to measure current induced by a moving magnetic field!

IntermediateProtip30 minutes2,397
Hacking STEM Electromagnetic Sensor

Things used in this project

Hardware components

Arduino UNO & Genuino UNO
Arduino UNO & Genuino UNO
×1
USB-A to B Cable
USB-A to B Cable
×1
Wire, Magnet
Wire, Magnet
×1
17 mm diameter magnet
×1
Adafruit Small Alligator Clip to Male Jumper Wires (2)
×1
paper
×1

Software apps and online services

Microsoft Data Streamer
Microsoft Data Streamer
Arduino IDE
Arduino IDE
Microsoft Excel

Hand tools and fabrication machines

sandpaper
ruler
Wire Stripper & Cutter, 18-10 AWG / 0.75-4mm² Capacity Wires
Wire Stripper & Cutter, 18-10 AWG / 0.75-4mm² Capacity Wires

Story

Read more

Schematics

Arduino Schematic

Connect your electromagnetic sensor to the Arduino Uno board as shown in the schematic

Code

Arduino Electromagnetic Sensor Code

Arduino
This code reads in the analog voltage for an electromagnetic sensor connected to Arduino pin A0, then prints the data to Serial Monitor which can be read and analyzed in Microsoft Excel via the Data Streamer add-in.
// ----------------------------------------------------------------------------
// Electromagnetic Sensor Code for use with the Sensor Library 
// available from Microsoft Education Workshop at http://aka.ms/data-streamer
// 
// This project uses an Arduino UNO microcontroller board. More information can
// be found by visiting the Arduino website: 
// https://www.arduino.cc/en/main/arduinoBoardUno 
//  
// This code reads in the analog voltage for an electromagnetic sensor connected
// to Arduino pin A0, then prints the data to Serial Monitor which can be read
// and analyzed in Microsoft Excel via the Data Streamer add-in.
// 
// Comments, contributions, suggestions, bug reports, and feature requests 
// are welcome! For source code and bug reports see: 
// http://github.com/[TODO github path to Hacking STEM] 
// 
// Copyright 2019, Microsoft EDU Workshop - HackingSTEM 
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
// of the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
// SOFTWARE. 
// ----------------------------------------------------------------------------

// Program variables ----------------------------------------------------------
int exampleVariable = 0;
int sensorPin = A0;

// Serial data variables ------------------------------------------------------
const byte kNumberOfChannelsFromExcel = 6; //Incoming Serial Data Array
// IMPORTANT: This must be equal to number of channels set in Data Streamer

const char kDelimiter = ',';    // Data Streamer expects a comma delimeter
const int kSerialInterval = 50;   // Interval between serial writes
unsigned long serialPreviousTime; // Timestamp to track serial interval

char* arr[kNumberOfChannelsFromExcel];

// SETUP ----------------------------------------------------------------------
void setup() {
  // Initializations occur here
  Serial.begin(9600);  
}

// START OF MAIN LOOP --------------------------------------------------------- 
void loop()
{
  // Process sensors
  processSensors();

  // Read Excel variables from serial port (Data Streamer)
  processIncomingSerial();

  // Process and send data to Excel via serial port (Data Streamer)
  processOutgoingSerial();

//   if ( strcmp ("Apple", arr[0]) == 0){ // Compares STR1 to STR2 returns 0 if true.
//       Serial.println("working");
//   }
}

// SENSOR INPUT CODE-----------------------------------------------------------
void processSensors() 
{
  // Add sensor processing code here
  exampleVariable = analogRead( sensorPin );
}

// Add any specialized methods and processing code here

// OUTGOING SERIAL DATA PROCESSING CODE----------------------------------------
void sendDataToSerial()
{
  // Send data out separated by a comma (kDelimiter)
  // Repeat next 2 lines of code for each variable sent:

  Serial.print(exampleVariable);
  Serial.print(kDelimiter);
  
  Serial.println(); // Add final line ending character only once
}

//-----------------------------------------------------------------------------
// DO NOT EDIT ANYTHING BELOW THIS LINE
//-----------------------------------------------------------------------------

// OUTGOING SERIAL DATA PROCESSING CODE----------------------------------------
void processOutgoingSerial()
{
   // Enter into this only when serial interval has elapsed
  if((millis() - serialPreviousTime) > kSerialInterval) 
  {
    serialPreviousTime = millis(); // Reset serial interval timestamp
    sendDataToSerial(); 
  }
}

// INCOMING SERIAL DATA PROCESSING CODE----------------------------------------
void processIncomingSerial()
{
  if(Serial.available()){
    parseData(GetSerialData());
  }
}

// Gathers bytes from serial port to build inputString
char* GetSerialData()
{
  static char inputString[64]; // Create a char array to store incoming data
  memset(inputString, 0, sizeof(inputString)); // Clear the memory from a pervious reading
  while (Serial.available()){
    Serial.readBytesUntil('\n', inputString, 64); //Read every byte in Serial buffer until line end or 64 bytes
  }
  return inputString;
}

// Seperate the data at each delimeter
void parseData(char data[])
{
    char *token = strtok(data, ","); // Find the first delimeter and return the token before it
    int index = 0; // Index to track storage in the array
    while (token != NULL){ // Char* strings terminate w/ a Null character. We'll keep running the command until we hit it
      arr[index] = token; // Assign the token to an array
      token = strtok(NULL, ","); // Conintue to the next delimeter
      index++; // incremenet index to store next value
    }
}

Credits

Hacking STEM

Hacking STEM

10 projects • 29 followers
Build affordable inquiry and project-based activities to visualize data across STEM curriculum.
Jen Fox

Jen Fox

17 projects • 47 followers
Dabbled in dark matter, settled into engineering w/ a blend of inventing and education! Founder/CEO of FoxBot Industries

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