Digital Thermometer using c# and a microcontroller

• Download WindowsFormsApplication4 - 501.38 KB

Introduction

 its a Digital Thermometer application which reads reading from serial port which are sent there by a hardware which calculates temperature frequently and transmits the readings to pc at a baud rate of 9600 bps    

 <img src="DigitalThermometer/thermometer.png"> 

Using the code 

First of all lets in the form load event initialise the serial port: 

			form1_load(object sender,eventargs e) 
{
portname = "COM4"; //global string variable
            parity = Parity.None; //global System.IO.Ports.Parity variable;
            BaudRate = 9600;      //global int variable   
            stopbits = StopBits.Two;    //global StopBits enum variable
            databits = 8;               //global int variable
              //global SerialPort variable
            port = new System.IO.Ports.SerialPort(portname);
            port.Parity = parity;
            port.BaudRate = BaudRate;
            port.StopBits = stopbits;
            port.DataBits = databits;
            port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
            port.Open();
 }           
	 <span class="Apple-style-span" style="font-family: Verdana; font-size: 16px; "> </span>

Next we write the code to collect readings from serial port, calculating temperature and then converting it to proper angle through which the arm is to be rotated

<span class="Apple-style-span" style="font-family: Verdana; font-size: 13px; white-space: normal; "><pre lang="cs">void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            port.Read(bt, 0, 1);
            sum += Convert.ToDouble(bt[0]) *voltage*100/255;
            
            count++;
            if (count == 100)
            {
                InitialTemp = temp;
                temp = sum / 100;
                sum = 0;
                count = 0;
                double angle = 0;
                if ((Math.Floor(temp) > 30 && Math.Floor(temp) <= 40) || (Math.Floor(temp) < 70 && Math.Floor(temp) > 60))
                {
                    if (Math.Floor(temp) <= 40)
                        angle = -65 + 3 * ((temp - 1) % 10) + 3;
                    else
                    {
                        angle = 35 + 3 * ((temp - 1) % 10) + 3;
                    }

                }
                else if ((Math.Floor(temp) > 40 && Math.Floor(temp) <= 50) || (Math.Floor(temp) <= 60 && Math.Floor(temp) >= 50))
                {
                    //if (temp == 60) System.Diagnostics.Debugger.Break();
                    if (Math.Floor(temp) <= 50)
                        angle = -35 + 35 * ((temp - 1) % 10) / 10 + 3.5;
                    else
                    {
                        //if (temp == 50)
                        //    System.Diagnostics.Debugger.Break();
                        angle = 35 * ((temp - 1) % 10) / 10 + 3.5;
                    }
                }
                else
                {
                    if (Math.Floor(temp) <= 30)
                        angle = -125 + 2 * temp;
                    else
                    {
                        angle = 65 + 2 * (temp - 70);
                    }
                }
                if (AnimationAllowed)
                    Animate(CurrentAngle, angle);
                
            }
            //throw new NotImplementedException();
            
        } 

and then finally the Form1_Paint event which paints the form : 

 private void Form1_Paint(object sender, PaintEventArgs e)
        {
            if (firsttime)
                if (AnimationAllowed)
                    AnimationAllowed = false;
            //t1.Enabled = false;
            try
            {
                surface.FillRectangle(Brushes.LightSteelBlue, DrawingRectangle);
                Image img = new Bitmap(Properties.Resources.speedometer, this.Size);
                Graphics ImageGraphics = Graphics.FromImage(img);
                Image hand = new Bitmap(Properties.Resources.MinuteHand);
                
                //handgraphics.TranslateTransform(hand.Width / 2, hand.Height / 2);
                
                //ImageGraphics.DrawImage(hand, new Point(this.Width / 2 -10, 40));
                surface.DrawImageUnscaled(img, new Point(0, 0));
                
                //e.Graphics.TranslateTransform(0,0);
                surface.TranslateTransform(this.Width / 2f, this.Height / 2f);
                
                surface.RotateTransform((float)CurrentAngle);
                

                surface.DrawImage(hand, new Point(-10, -this.Height / 2 + 40));
                

                string stringtemp = displaytemp.ToString(); //InitialTemp.ToString(); //temp.ToString();
                stringtemp = stringtemp.Length > 5 ? stringtemp.Remove(5, stringtemp.Length - 5) : stringtemp;
                Font fnt = new Font("Arial", 20);
                SizeF siz = surface.MeasureString(stringtemp, fnt);
                surface.ResetTransform();
                

                LinearGradientBrush gd = new LinearGradientBrush(new Point(0,(int)siz.Height + 20), new Point((int)siz.Width,0), Color.Red, Color.Lavender);
                surface.DrawString(stringtemp, fnt, gd, new PointF(DrawingRectangle.Width / 2 - siz.Width / 2, 70));
                

                surface.DrawEllipse(Pens.LightGray, DrawingRectangle);
                
                
                buff.Render();
                if (firsttime)
                {
                    firsttime = false;
                    AnimationAllowed = true;
                }
            }
            catch (InvalidOperationException)
            {
                
                
            }
            
            //MessageBox.Show(count.ToString());
            //t1.Enabled = true;
        } 

Points of Interest

this tells how we can read serial port data and then use it in applications.

the hardware is also my self creation.  

For Hardware details, leave me a message 

History

Keep a running update of any changes or improvements you've made here.