Week 11

Tittle

• Try coding Arduino for heart rate measurement

Objective

• To investigate and understand the accelerometer coding
• To combine the accelerometer coding with heart rate coding

Content/procedure

• At this stage we need to do many try and error.
• Found in the internet, how to get the actual value of the accelerometer. Means from that, we need to have mathematical expression for the ADXL 335 accelerometer coding. We must considered the voltage supply value  to the accelerometer and the sensitivity of the accelerometer

Result/Analysis

• After many try and error, finally we got the mathematical coding for the accelerometer.The mathematical shown below:

y/512.30*1.5-1.6)/0.33

• For the threshold value ,the calculation is shown and will be explain in the report

Conclusion

• The accelerometer coding will combine with heart rate coding. For the heart rate, we multiply the sensor reading with 60 second.
• Full Arduino program code is in the final project report .

Week 10

 Title

• Testing the heart rate circuit

Objective

• to observe the accuracy of accelerometer which act as a sensor,it will measure heart rate.
• to investigate other component accuracy such as instrumentation amplifier,operational amplifier and timer

Content/procedure

• After construct the circuit in week 9, tend to testing the circuit by using oscilloscope in order to show the results
• from the oscilloscope we need to observe the peak or amplitude voltage that the accelerometer can reach.

Result/Analysis

• When we tap or move the accelerometer ,signal will raised or reach certain peak.Amplitude is the maximum voltage reached by the signal. 

It is measured in volts, V.Peak voltage is another name for amplitude.

-Voltage is shown on the vertical y-axis and the scale is determined by the Y AMPLIFIER (VOLTS/CM) control. Voltage = distance in cm × volts/cm

-Time is shown on the horizontal x-axis and the scale is determined by the TIMEBASE (TIME/CM) control. Time = distance in cm × time/cm

I

 Conclusion

• Testing circuit need more time in order to get the correct result.

Week 9

Title

• Construct circuit for heart rate measurement using accelerometer

Objective

• to design the schematic diagram for heart rate circuit
• to construct the accelerometer heart rate ciruit

Content/procedure

• tried to combine and altered the schematic diagram from the internet to get the suitable heart rate circuit

Result/Analysis

• After several alteration from 2 ECG circuits found in the internet, finally get the schematic diagram that suits with the accelerometer sensor.The schematic diagram is shown below:

 

Conclusion

• This circuit is under testing.
• The first stage testing is to get the peak of the accelerometer so then we can get the threshold value that been use for the programming part.Threshold value is for accelerometer that we used as a sensor.
• Threshold as mentioned in the flow chart  is the way we used to get the heart rate in digital form.Accelerometer is moving up and down,so when the accelerometer is achieve above the the threshold value,it will triggered the next program code.

Week 8

Title

• Order and buy some component for heart rate circuit measurement

 Objective

• To construct heart rate circuit measurement,so we need to but all the component needed

Content/procedure

• Went to Jalan Pasar and order AD524AD.AD524 need to order first at SIM supplier but other component such LM741 and NE555 timer is available at Nixie

Result/Analysis

• After deep research,AD524 AD precision instrumentation amplifier which act as preamplifier is suitable to be used in measurement of heart rate because its gain can be set to 1000 by short Pin 3 and Pin 11.

LM741- The 741 is connected as a source follower.  The output DC voltage of the AD524 is maintained to 3V.

NE555- The 555 monolithic timing circuit is a highly stable controller capable of producing accurate time delays, or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor.

 

 Conclusion

• Circuit is developed on the breadboard
• We testing the circuit by display the result at the oscilloscope
• to power up the circuit,we used function generator first  for supply

Week 7

Title

• Design flow chart for programming flow of Arduino

Objective

• to get the picture on how to do the programmed of arduino before proceed in developed  coding heart rate

Content/procedure

• find in the internet the example of flow chart of arduino program

Result/Analysis

• flow chart is shown  below

Conclusion

• We need to design flow chart first before proceed in developed coding
• Flow chart is important because from the flow chart we know how to begin or start,process and end our programmed
• Threshold program need to be used in this project,because we need to find the peak of the accelerometer can achieve.Then,ADXL 335 accelerometer coding need to deeply understand before combine with heart rate coding.