Measure. Analyze. Learn.
Hello, I'm John Melville from Vernier software and technology.
And I'm going to show you how to get nice clean EKG traces,
on your computer or LabQuest 2.
What I need to tell you first though,
is there are things called electronic noise
that may be in your classroom.
Luckily, there's some really simple things you can do
to minimize electronic noise.
If you follow these key tricks,
you should get very nice clean the EKG traces.
The biggest problem in most cases
can be noise from a power supply.
So, to get a nice clean EKG trace, what I would recommend
is disconnecting power from your LabQuest or computer.
The other thing you need to do is to make sure
you have a nice good contact of the electrode with your skin.
If you can wait just a few minutes before you record an EKG
after you put these on, you'll get a much cleaner trace.
Another thing that you should be aware of is that cell phones,
and other electronic devices also throw noise.
So if your students, or you, have a cell phone I your pocket
you should remove that cell phone from your pocket,
and don't allow it near the EKG sensor.
The key is to keep the EKG sensor as far away from anything that
can produce, or what we call throw, electronic noise as possible.
Now, luckily, the body is a great electronic shield.
So, if you were to put this EKG sensor, the box, in your pocket,
that's one way to reduce noise. The other way is just to have
your students put this in their hand.
And that is what I am going to demonstrate to you.
So, I'm going to unwrap these wires.
Move this over a little bit.
And I'm going to connect the EKG sensor to myself.
These are the leads; red goes left,
green goes right,
and black is what we call the reference.
And, I like to put that on just a
bony protuberance on my wrist here.
Then, I'm going to put this in my hand.
And, I am now shielding this little EKG sensor.
All right, so, I need to hit the collect button on the computer,
but my hand is still acting as a shield.
I'm going to move away from the electronics,
so that there's going to be very little interference.
I also need to stand very still, so I don't also create noise
in the electronic trace.
So, I'm going to step back.
And then, I'm going to hit the collect button.
And, I'm going to stand still while I do that.
And there you go; we have four nice EKG traces.
Now, there are some other ways that we can clean this up.
In LoggerPro there actually is an experiment file that you
can open up to record data, and we smooth the data
to make it look even cleaner.
And, I can very simply show you how to do that.
So, if you go to "File" - "Open...",
this will take you to the "Experiments" folder.
And then, if we go to "_Human Physiology w Vernier",
there is an actual file called "{12} Analyzing Heart [with] EKG"
And if you open this file, this will record an EKG,
and it will do something we call smoothing,
which will also make the EKG trace look very clean and nice.
So, what I'm going to do again here is,
once again, it will record for three seconds.
I'm going to pick up the EKG sensor.
Now, I'm going to record EKG so you can
see the difference with this file.
I'm going to hold it up again, and I'm going to sit very still.
Remember, you need to sit still;
move it away from the electronics;
and then, just hit collect.
And hopefully you can see that's even a much
nicer and cleaner EKG trace.
So, if you don't have a computer in your classroom,
or you want to use our LabQuest as a standalone device,
like this device here, our LabQuest 2, the most important
thing to remember is to not have it connected to AC power.
This goes for our LabQuest 2, and our LabQuest 1,
the original LabQuest.
You want to make sure it's not attached to AC power.
And really, that isn't that big of a deal if your recording an EKG,
because you're only going to record it,
in most cases for 3 seconds. So, it's really ok
if the power is not connected for just a short time.
So, let me just show you how to do that on a LabQuest.
I'm going to just disconnect the EKG sensor.
And, I'm going to plug it into the LabQuest.
Once again, it auto-ids, so it's going to be recognized,
and it's already set up to record for three seconds.
And then, I'm just going to repeat everything I just did.
I'm going to hold the EKG sensor in my hand,
I'm going to sit still, and then I'm going to hit the collect button.
And just remember, that I also need to make sure that I don't
have any electronic devices in my pocket.
I want to make sure the EKG sensor is far away from a
monitor or other electronic devices.
So, I'm going to move back a little bit.
And then, I'm just going to tap on the collect button,
right here on the LabQuest.
And, if you follow all these instructions,
you should get a really nice EKG trace, just like I did right here.
So, for more information about EKG sensors,
or human physiology with Vernier probes,
just go to our web site at www.vernier.com.