Audioguru
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Fuzzy photos don't show the schematic of it.Sam_t said:Hello ! I've bought a mini blood preasure and heart beat device, digital ( portable ) and I don't know how to connect it to a electronic plate and then to the computer. How do I stick the wires to that plate ? I need it for my school project. I've attached some photos of the device. Please reply me a.s.a.p. it will mean the world to me. Thank you.
aredhel said:The project is almost done now, took a long time I know. I was wondering if anyone can suggest me better methods to hook myself to my hardware?
Right now I am using crocodile clippers with a normal jumper wire connecting the crocodile clip to the PCB. Since I planning to give my PCB a casing, does anyone know of another/better method of connection from the electrodes to the hardware?
eng_shady00 said:Hi,
I've read all ur topics unil u've finished ur project. Congratulations!!!
First, about ur question, there is sockets something contents of 2 parts male and female.. it's something like snap fastener (like the one in ur shirt ).
There's also some thing similar to the audio jack with its female part which can be fixed in ur PCB.
Also ther're sockets called banana with 2 parts.
For all of the above, one part is fixed to ur board and the other connected to the patient cable.
U also may buy ECG patient cables which used in hospital's monitors. U can find it in shops of biomedical equipments.
I'm making a project of an ECG monitor. But the difference is that i want to display the signal on pc including calculating the heart rate in a small program using matlab's GUI. I've built my circuit but the same problem occurs, NOISE.
1-Can u please send the last design that give a clear signal.
2-Did u use all the HPF, LPF & Notch filters ?? or what?
3-Did u use an ordinary CRO to check ur signal ? I can't get a solid line signal on CRO, but i could adjust it to view a moving dot takes a shape of the ECG signal.
4-Did u use pic or adc.
5-Could u connect ur board to pc ? how ? Does the usb connection work?
Wish u may help me until i finish my project like u.
Thanks alot.
There is no opamp called an OP17 unless it is very old and is not made anymore.ranggaperdana_06114 said:how about OP17 ?
The OP07 is pretty good and will work fine in this circuit. many of its features are not used.ranggaperdana_06114 said:ops.. i'm sorry. i mean with OP07 and OP97
Audioguru said:A TL071 low noise opamp has 1/3rd the noise of a lousy old 741 opamp.
An OP134 has 1/7th the noise of a lousy old 741 opamp.
An LM4562 dual opamp has 1/20th the noise of a lousy old 741 opamp.
There are many opamps better than a lousy old ...
I have made 3rd-order Butterworth filters with a single opamp. Higher orders can be made with a TL072 dual opamp or a TL074 quad opamp.eng_shady00 said:For a heigher order LPF, can i use TL074?
The LM358 is horrible. the AD620 is OK.What about LM358 and AD620.
Should i replace them also?
The patient side of an opto-isolator needs to be powered by something like a battery so you might as well power the entire circuit from a battery.Please, I've another request:
Can u please help me in choosing an optocoupler isolator to use in my ECG circuit? A one with a suitable cost and that i can find in market.
I saw many data sheets, but can't choose one.
I've 3 patient leads, connected to right arm, left arm & left leg.
I want to separate the patient from the rest of the cicuit.
Will the optocoupler powered from my power supply?
Or this may also be dangerous for patient?
how can i fully isolate the patient?
Thanks in advance.
I went through this entire thread to find the circuit that shines an LED through a finger to detect blood flow.eng_shady00 said:Thanks alot.
U really helped me and many others.
But please can u specify an opto-isolator. I wish it can be quad or multi, if their exist.
Also, What's the equevalent to LM358?
Best regards.
Also, can the opto-isolator be replaced with 2 diodes in reverse polar connected to ground for each lead.
If yes, how should i choose my diodes.
Thanks again
Audioguru said:It does not have an "opto-isolator". It has an LED shining though a finger to a light-dependent-resistor.
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