Thursday, December 16, 2010

Cool Toys for HVAC/R Instructors!

Document camera? I thought this thing was an air conditioning component magnification system! I have been learning to use my new toys this quarter. I was given a document camera and video projector for my class room. Many people know these things as Elmos because that is who developed the first ones. If you are unfamiliar with them, they are able to zoom into a document placed on them so that you can project it to a screen using a video projector. That is OK, but what I use it for is projecting images of components and tools. Put a defrost board on it, zoom into the defrost setting jumpers, and show how to set the time on an electronic time-temperature defrost board. Look at the color bands on resistors. Ohm the coil out on a relay and show the meter as you ohm the coil out. Wire a simple circuit and operate it, then measure the voltage drop across the switch. Disassemble a TEV and show the difference between an internal and external TEV. Show the difference between the wire gauge of the run and start winding on a split phase motor. I am just getting started, but I think you get the drift. You can show detail in real time and everyone can see and follow what you are doing even better than if they were standing beside you. Having drawn many extemporaneous works of art on the white board, I still sometimes revert to my older chalk and talk methodology. Elmo helps there as well. If I really feel the need to scribble, I can draw on a piece of paper and project the drawing. If the scale is not quite right, the zoom lets me show it off to full advantage and I don’t have to clean the white board afterwards. I have an internet connected computer in the podium as well. The video projector works great for showing MyHVACLab on the screen. When we discuss the questions at the end of the units, I project the e-book from MyHVACLab. Then I can show relevant information from the book as we review the unit and the students can follow along in their textbooks. I use the mouse to point out any particular coverage in the book I want to highlight. Of course the video projector also works for showing powerpoint presentations and video clips, but I have not shown any videos yet because I am too busy showing all the cool HVAC/R parts. I have a large collection all around my podium of things I have confiscated from the lab, including a few unit panels. If someone asks a question about a part I don’t have I am likely to find one by the next class. I got the idea I wanted to show the phase shifts caused by inductive reactance and capacitive reactance. The electronics department loaned me a digital dual trace oscilloscope that is small enugh to fit on the Elmo. I am going to build a circuit to show phase shift on the oscilloscope. I know lots of text books have drawings of this, but I don’t think many students pay a lot of attention to them. I am hoping when they see the shift occur right in front of them on the big screen in real time the information will sink in. At the very least, I know that I will have a good time playing with my new toys. I hope my students will see how cool this all is and want to play too.   

1 comment:

  1. I don't really think it's viable to get HVAC estimates on line, unless of course you already know exactly what is wrong. HVAC