If a heart rate monitor is too expensive to purchase, anyone can learn how to make a heart rate monitor for very little cost. Heart rate monitors are useful in determining the heart’s state in various situations. Making a heart rate monitor requires using devices intended for specific purposes and altering them. Recognize that after altering these gadgets they will no longer operate as they were designed. Testing the heart rate monitor requires a data logging and graphing software, like Robolab 2.0, which is may be found online for little to no cost. Making a heart rate monitor can be an exciting challenge, however exercise caution when using any device using electricity.
In order to make a heart rate monitor you will need:
- Polar Chest Strap
- Mindstorm RCX Lego
- Small light sensor, Lego
- Soldering gun
- Soldering wires
- White, red and green alligator leads
- Small motion sensor
- Serial adapter
- Use a bit of force to remove the brown plate on the underside of the Lego light sensor. Find the positive and ground soldering points for the three leads. Solder one wire onto the positive and ground point each. Solder the final wire to the signal collector point, positioned next to the microprocessor.
- Detach the master light sensor on the Lego piece. Connect the white alligator lead to the wire soldered to the ground point. Connect the red alligator lead to the positive wire soldered to the positive point. Connect the green alligator lead to the wire soldered onto the signal connector point. Verify the wires do not cross or touch.
- Attach each alligator lead to the respective serial adapter wire. Attach the signal alligator lead to the pin-out farthest left on the serial adapter. Connect the positive alligator lead to the next pin-out to the right. Connect the ground alligator lead to the pin-out second from the right, two over from the positive alligator lead.
- Plug the serial adapter into the serial port on the small motion sensor. Connect the light sensor into the Mindstorm RCX Lego. Connect the motion sensor to the chest strap and strap it onto the test individual above the heart.
- Turning on the Mindstorm RCX Lego is the final step in making a heart rate monitor. Instruct the test individual to perform a physical exercise like jumping jacks. The person’s heart rate should register with the RCX Lego and the device should be plugged into a computer to view the results using the proper data analysis software.