Any Way To Simulate Human Temperature Taking?

I am trying to simulate human temperature taking. Basic I just need a button, a textbox , a progress bar and a timer. What I want to do is that when the button is clicked, the progress bar will slowly increment and after it reaches maximum, a random number in the range 35-40 will be generated in the text box.

Now so far, this is what I've done:
Public Class Health
Private Sub Health_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Start()
[Code] .....

So this is suppose to be a temperature gadget for kids and therefore when a certain amount of temperature is reached...an alarm is sent to the parents. So the progress bar is working fine. The random number generator too. A "sent" dialog box is open if the temperature is >38.
1-The number is working. But I would like the number to b e generated AFTER the progress bar reaches maximum.
2-The sent dialog box is open basically the moment I click on the button to start the progress bar (if the num generated is>38). And it keeps up looping and opening.