Discussion in "General help Guidance and Discussion" started by    xmen    Feb 16, 2008.
Sat Feb 16 2008, 04:19 PM
hi.........i need sensor to detect our heart beat .... anything available please guide me.......

[ Edited Wed Feb 27 2008, 01:21 AM ]
Mon Feb 25 2008, 03:14 PM
use super bright led and LDR
Tue Feb 26 2008, 04:01 AM
hi TPS, can you explain how LED and LDR can help to detect heart beat?
Sun Mar 02 2008, 01:10 PM

hi TPS, can you explain how LED and LDR can help to detect heart beat?


Mon Mar 03 2008, 02:46 PM
curtsy binu

[ Edited Mon Mar 03 2008, 02:47 PM ]
Tue Mar 04 2008, 12:46 PM
thank you TPS
and... i hope binu has no problem with sharing his circuits
Tue Mar 04 2008, 02:19 PM
YES I hope so
Tue Mar 04 2008, 02:51 PM
just one thing now.. how putting this sensor on finger can detect heart beat?
what is connection of heart beat with IR sensor? :-s
Tue Mar 04 2008, 04:19 PM

Heart beat is sensed by using a high intensity type LED and LDR. The finger is placed between the LED and LDR. As Sensor a photo diode or a photo transistor can be used. The skin may be illuminated with visible (red) using transmitted or reflected light for detection. The very small changes in reflectivity or in transmittance caused by the varying blood content of human tissue are almost invisible. Various noise sources may produce disturbance signals with amplitudes equal or even higher than the amplitude of the pulse signal. Valid pulse measurement therefore requires extensive preprocessing of the raw signal.
The new signal processing approach presented here combines analog and digital signal processing in a way that both parts can be kept simple but in combination are very effective in suppressing disturbance signals. The setup described here uses a red LED for transmitted light illumination and a LDR as detector. With only slight changes in the preamplifier circuit the same hardware and software could be used with other illumination and detection concepts. The detectors photo current (AC Part) is converted to voltage and amplified by an operational amplifier (LM358). Output is given to another non-inverting input of the same LM358; here the second amplification is done. The value is preset in the inverting input, the amplified value is compared with preset value if any abnormal condition occurs it will generate an interrupt to the controller AT89C2051.


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Thu Apr 17 2014, 05:32 PM
Thu Apr 17 2014, 10:19 AM
Thu Apr 17 2014, 08:44 AM
Wed Apr 16 2014, 07:32 AM
Tue Apr 15 2014, 04:12 PM
Tue Apr 15 2014, 11:21 AM
Mon Apr 14 2014, 10:00 PM
Sun Apr 13 2014, 02:59 PM


Thu Apr 17 2014, 01:23 PM
@mba Great .. please do.
Thu Apr 17 2014, 12:27 AM
like the forum and wish to participate
Wed Apr 16 2014, 04:45 PM
@viniciusheidrun..you should read my comment just before your post
Wed Apr 16 2014, 01:43 PM
I'm doing a drive system with SIM900D modem and microcontroller AT89S52 via sms. I'm having trouble can not generate the. Hex to send to the microcontroller, whenever I compile the error, I'm using MCU 8051 IDE, what should I do so that my system receive sms and perform my task?
Mon Apr 14 2014, 01:00 PM
@Haranadh,bipin chandra etc. Create threads for your questions.
Sun Apr 13 2014, 04:05 AM
we bought HC 06 Bluetooth modem instead of Module ,Can any one help me of using it as bluetooth module since i am doing this project?
Sun Apr 13 2014, 03:58 AM
Hi,Actually we bought Bluetooth modem instead of Bluetooth Module
Sat Apr 12 2014, 02:55 PM
Please use forum if you want to ask a question.
Sat Apr 12 2014, 01:06 PM
Hi Ahana,I can Help you on this
Sat Apr 12 2014, 03:51 AM
bipin chandra
can anybody help me. we are making a project to control the position of dc motor. so there we need to interface lcd screen and the 4X3 memberane keypad and a dc motor driver chip. can anybody please give me the complete circuit diagram connection of these components with the 8051.and alse help in the programming. my email id is bipin.chandra666@gmail.com
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