Vernier Heart Rate Monitor Lab

This lab introduces the student to the Vernier Hand-Grip Heart Rate Monitor. The

student must learn how to connect to the ELVIS II prototyping board to make the

necessary signal connections for the sensor.

Theory:

Vernier offers a sensor that detects a heartbeat through the use of electrodes. The person

conducting the experiment holds the heart rate monitor, which communicates wirelessly

with the receiver. Each heartbeat detected triggers a 3-volt signal which can be measured

with NI ELVIS II.

How to build the experiment:

The heart rate monitor receiver is attached to the Analog Proto Board Connector (BTA-

ELV), which is connected to the NI-ELVIS II prototyping board.

Figure 1 and the following steps show how to wire the connector.

Figure 1: Prototyping Board for the Vernier Hand-Grip Heart Rate Monitor

Wire the following pins:

1) AI 0+ to SIG 1 of the Analog Proto Board Connector

2) ELVIS DC Power Supply +5V to 5 V pin of the Analog Proto Board Connector

3) ELVIS DC Power Supply Ground to GND pin of the Analog Proto Board

Connector

4) AIGND to GND pin of the Analog Proto Board Connector

How the Heart Rate Monitor VI runs:

1) Timing Configuration: The sample rate and length of the experiment are chosen

on the front panel. The VI will terminate once the specified amount of time has

passed. It may end earlier if the stop button is pressed or an error is encountered.

The Elapsed Time VI compares the elapsed time to the target time.

2) DAQ Assistant: The DAQ Assistant is configured for ai0, returning the data from

the Heart Rate Monitor.

3) Displaying the Data: The voltage from the Heart Rate Monitor is displayed on the

Signal chart.

4) Analysis: The DataCollect_BeatsPerMinute subVI calculates the beats per

minute, which is given as a numeric as well as on the Beats Per Minute chart.

This is accomplished by detecting peaks in the signal.

Figure 2 below shows the LabVIEW code.

Figure 2: Heart Rate Monitor VI Block Diagram

Running the Heart Rate Monitor VI:

Before running the Heart Rate Monitor VI, verify that the physical channel selected is ai0

on your ELVIS II device. You can configure this by double clicking the DAQ Assistant

on the Block Diagram.

Make sure the arrows on the receiver and the hand grips are pointing up. Stand three feet

or less from the receiver to ensure the information is transmitted properly. Hold the

Heart Rate Monitor according to the positions of the palm and fingers indicated on the

device. The proper technique is shown in Figure 3.

Figure 3: Position of Heart Rate Monitor

Press the Run button and wait for the peaks and heartbeat data to display, as seen in

Figure 4.

Figure 4: Heart Rate Monitor Front Panel

Summary:

With the Vernier sensors, you can take advantage of NI ELVIS II to acquire data by

plugging in with a simple Proto Board Connector. Collect analog data from the Hand-

Grip Heart Rate Monitor using NI ELVIS II. Then use LabVIEW to display a visual

representation of a heartbeat and calculate beats per minute.