Practical Design Group, LLC

Take readings from the THUM using your own programs

THUM ActiveX Control

The THUM OCX is an ActiveX control that allows custom applications to be written that reads temperature, RH, and dew point measurements from the THUM. This adds a great deal of flexibility to the THUM. Temperature/RH measurements can easily be taken and integrated into any ActiveX compatible project or solution.

The THUM OCX can be used in programming environments such as Visual Basic, Visual C, Delphi, VB script, VBA, Labview, etc.
Click here for Labview instructions.

Note: msvbvm60.dll is required for this OCX

The OCX is very easy to use.  Install the ocx on the development computer using the installation program.  Add the control to your project and use some simple code to acquire the readings.

Methods

THUMocx1.Read - tells THUM to make a reading

Properties

THUMocx1.Unit - sets or returns the current unit of temperature and dew point readings read/write - valid values F and C
THUMocx1.Temp - returns last temperature reading - read only THUMocx1.RH - returns last RH reading - read only
THUMocx1.DewPt - returns last Dew point reading - read only

Note: Readings can not be taken from the THUM faster than one reading every 3 seconds. Taking readings faster than this could raise the internal temperature of the sensor. This could skew the temperature and RH readings returned from the THUM.

License:

We require that you purchase one copy of a control per developer on a project. If this is met, you may distribute the control with your application royalty free. You may never distribute the license file or installation program for the license file.

Sample Visual Basic code to read values from the THUM

'Add a THUMOCX control to a form and name it THUMocx1
'Reads from THUM and returns temp and dew point values in °C
Dim returnvalue As Integer
Dim msg1 As String

'set Temperature/Dew point Unit
'Valid values are "F" or "C"
'if a non valid value is sent to the control the control will reset the Unit to "F"
THUMocx1.Unit = "C"

'tell THUM to take a reading
returnvalue = THUMocx1.Read

'Check to see if reading was successful
If returnvalue = 1 Then
'successful read
Else
'failed read
msg1 = "Temp Humidity Sensor was not found." & Chr(10) & "Please verifiy it is plugged into a USB port."
Call MsgBox(msg1, vbExclamation, App.Title)
Exit Sub
End If


'display values from last reading in labels
lblTemp.Caption = THUMocx1.Temp
lblRH.Caption = THUMocx1.RH
lblDewpt.Caption = THUMocx1.DewPt