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ARDUINO DIY Pulse Oximeter lm386 arduino project

okay Marcelino first but we had just like later in introduction of our what we have made and not resolved Renata me to use in our LM the three eight six which is an audio path so basically back to cable which is very important our part how to make cable in making cable we need to know first off we need to connect three wires even if we have four connections and for that we will use audio cable which has ground connected to this are baked layer which is first ring then we have power five volts that will power LED connected here and we have power on five volts connected to infrared detector through the resistors obviously and this one is going through resistors which is a hundred fifty ohms that middle one and I used pot which is one case so that gives me really a lot of control of the light and on detector we have around 200 K not just resistor we have a a t 3k resistor and we have a hundred K pot potentiometer so let's get back now to how we need to connect our light first light you can use your multimeter and connect our black one to let's say this wire which is minus here and red one here and if you get your LED light to actually show you a light little bit of light then you have that connection right if you don't swap it simple eyes so you want your negative to be on this side and positive on this side in this example your detector collectors well to multimeter connect to let's say to Meg on your multimeter and put black one let's say on one side and red on the other side and move it around in daylight and you'll notice where you have biggest source of daylight that actually resistance changes if you notice that and your black one is connected on multimeter on this side red one on this one then you have them right way now you need to connect your negatives into one and we have done that by doing like this yeah and then on our cable we'll have ground which is brown and blue one which is power in 5 volts to infrared LED and the red one will power let's say your detector so let's get back now to cable connect multimeter to a blue one let's say or whichever color it is first connect multimeter to ground black one and find with your other end of your multimeter ground here then connect to any wire and if you detect that middle one and that happens that this is below one then below one you will connect to your led and connect multimeter to your read and then connect it to your bottom wall so there are more days of collect let's get back ground to multimeter and check it here where they get reading then connect your detector or multimeter here and connect it on bottom one and you should get reading then connect your blue wire and middle one in this section my and you should get reading so if you connected everything right that's how it should be on your Jack audio jack you have ground connected here and that will be connected when you plug it in to this one you have your LED light on your this side and these two are like one they're connected anyway and on the other side you have two they are connected as well so it doesn't matter the work is one so that will be your detector for this example I have used infrared LED and detector which is rated as nine hundred nanometers and that's very important so if you have connected everything right this is how we should look so picture it or freeze it or you can slow it stop it and that's it you can make your cable and make your fingertip finger claimed for your finger so we will move now on to schematics which is in this example I don't need this made those connections at all okay we're going back to Jack so we have here ground and it goes right to ground here we have five volts from going from here and those five volts are split into one is powering detector through a hundred K bot and it goes in a t 3k resistor and it goes right in your audio jack like we explained in previous example and then your signal when you receive some if you don't receive energy will be 5 volts so if you have 200 K roughly sensitivity here and if you receive signal it will drive it to the ground so your signal to will depend will be different between 5 and 0 obviously because of 200 K won't be really that much down to 0 but 0 volts but you will be able to fine tune it yourself this this way then signal goes out into capacitor I will get back to signal after so we go now 1 5 volts again goes here under this resistor and it goes back on to 150 ohms resistor and it goes on the thought 1k and it goes right in your jack and that powers your light when you turn it to turn port to minimum actually on these days 150 ohms and that's full power when turn this to maximum then your LED will be really weak and that's what you want to set it up to really week when you start getting your signal and then gradually increase it it's very important because you will not get signal and you will be disappointed then once you get signal here on the screen then increase sensitivity of your so previously you have to put this fault to minimum as well that means on this side actually and then gradually increase it and you will get a signal so alkylation now we have signal signal is coming out here and it goes in the capacitor which is not sure what capacitor have put in this schematics probably I think God I think it's 1uf and it goes through 83k writing your PIN on your LM pin number 3 your LM is turned up this way you have that little mark that's your pin 1 2 3 4 5 6 7 8 7 is bypass and we don't need it in this example so our signal went in pin number 3 number 2 is one of the inputs as well but it's attached to the ground ground is attached to pin number 4 and pin number 6 is 5 volts that we get from this as well and we power our LM on LM we have one interesting thing to control the gain if we take all this off and don't connect anything to pin number 1 and 8 we have 20 gain of 20 but if we connect only one the capacitor of 10uf without this pot we will get 200 again and I put 1k pot so I can actually find G on it here and capacitor has to be this end has to go positive site has to definitely end up on pin number one and your negative side of your capacitor has to end up on pin number eight so now when we have signal we can move on to filtering signal goes here like that and it goes in I have changed this in reality I put one pot of 10k and then in series I connected 22 K resistor and then that goes travels further down but here we break it with an capacitor and ground it here to ground this wire is connected to ground as we can say it goes here to ground so value of this capacitor is 0.47 UF and resistor plus spot is 32 okay I have 22 K resistor in series connected with 10k pot that's 32 when you do your calculation that will give you a low pass filter be ranging between thirty three heads and seventy two so you can get rid of your 60 Hertz signal goes further down to a hundred K resistor and 104 rated-r capacitor which is ceramic or value of that capacitor is zero point one UF you drive your signal here and this R have added only 400 470 K resistor to ground to get rid of some impedance but you can get it out and it will just work fine as well and then signal travels around and it goes right in your pin number a 1 a 0 that's your analog zero and that's when you get your signal these in middle section you can exclude are made for reading signal after first low-pass after second and we don't need it for this example it could be excluded let's move on on to the real signal now okay okay let's move on to signal now that's the region but we get and so if someone knows little bit about they signal you can see that you have to section peak when it goes really open then a half way it stops and it moves the other way forward and then it goes down this is what you can witness on the screen is my PVC that's what is called three must show of an tickler contraction and it's just because my heart is not pumping or equally right and as you can see there is a gap between now this is okay I made it our programmer when it finishes so about a hundred thousand samples a chest are closest but I can just reactivate it and it will do a hundred samples so more or less aw this isn't of it actually how we'd make it and what you get is pretty good clean signal I would mention only that if you talking about 61st noise in this example you will get 61st noise only if you have light in row because light bulb flashes about 60 times in second and that's reflected through your finger on detector as well so if it's no light in your room you will notice that you don't have any noise but noise we can reduce on virtually using that filter which we have and that BOTS so more less so that's it I hope you can recreate it up I'll put this all downloadable so can download it and I will make PDF file which is our like it will be like manuals who can actually have all details to talk you through and explain everything where you can fail and what you need to put the attention but I'm sure that you will get the same signal as I do and then we can do that to detect our detect our heartbeat and everything and I'll make more little function as well to do that on later I have made in this program actually each of these bars as you can see is 250 milliseconds so you can actually if you calculate the gap you can tell what's your heartbeat and then divide it divide number of milliseconds by 60,000 you will get actually heartbeat and that's what hope is useful to all of you computer-created ha and makes for yourself thank you for watching


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