13-09-2014, 12:04 AM
Heart Rate Monitor Project Circuit Diagram
Heartbeat Monitor Project Circuit Heartbeat Monitor Project Circuit with Tachycardia Alarm
Components Required for Digital Heartbeat Monitor Project Circuit
IC 4026 x 2
IC 74LS21
IC 555 x2
Transistor (BC548x3)
Resistor (1Kx4, 10Kx3, 68K, 220K, 820×2, 100×2)
Capacitor (1000µF/16V, 1µF/16V, 0.01µF x 2)
Seven segment display x2 (common cathode)
LED x3
Push button x3
Buzzer (5V)
Heart beat sensor
Working of Heart Beat Monitor Circuit
Now let’s discuss about working of heart beat monitoring system project
The 1st part is Heart Beat Sensor module, It is available in common electronics shops. Heart beat sensor is an embedded package module having 3 terminals Vcc, Ground and Out.
Heart beat sensor Module Heartbeat Monitor Project Circuit with Tachycardia Alarm
It senses the heart rate once you hold the sensing area with finger and produces small electrical signal output with respect to the Heart rate. These signals manipulated and amplified by our circuit.
A mono stable using 555 timer is designed for 1 minute which is used to enable the clock to the counter for one minute.
Another mono stable circuit intended for giving perfect clock to the counter which helps to remove the noise effect.
IC 74LS21 is a four input AND gate IC, used to connect the clock to the counter IC after getting the enable signals, also it helps to enable the buzzer when the count reach at 80.
AND gate will enable clock for one minute with the help of mono stable (designed for 1 minute).
When the push button (start count) is pressed, then the mono stable output is high for one minute and counter start counting if the heart beat sensor is connected.
After one minute mono stable OFF and thus clock will disable by AND gate and reading can be taken from the seven segment display.
If the number of pulses are greater than 80 then AND gate output is get in to high.
Output of AND gate is fed to transistor through 1K resistor, so transistor turns ON the buzzer and produces alarm sound.
2nd AND gate used to check whether the count value is greater than 80, the process is achieved by connecting the outputs (6, 7, 11, 12) of 4026 to the four inputs AND gate, AND output will high only when the counter output is 80.
IC 74LS21 is sensitive to input supply voltage. The maximum rating of this IC is +5V, so please use voltage regulator circuit using 7805 IC.