MolecularD

4 seconds x 25 Hz = 100 samples. C arrays are indexed from 0, thus the sample indices run from 0 to 99. To mean-center these indices first calculate the mean ( = 49.5), then subtract it from each index and you get 0 - 49.5 = -49.5, 1 - 49.5 = -44.5, etc.

I am glad it is working now. It is impossible for me to tell why you see results so seldom without knowing much more details about your project. It could be a million different things. Uncomment #define DEBUG to capture raw data in Serial monitor. Next, for debugging instructions as well as some tips please follow this linkhttps://github.com/aromring/MAX30102_by_RF/blob/ma...then scroll down to "How to report bugs" section.

Here is the sum calculated in Excel to dispel any doubts: it is 83325, indeed. Try it yourself. Your formula, I think, applies to numbers from 1 to n only.Now, the matter of unchanging results is concerning since my device's results do change as I wrote in other answers below. If you think it's the result of a bug in my code, then for debugging instructions as well as some tips please follow this linkhttps://github.com/aromring/MAX30102_by_RF/blob/ma...then scroll down to "How to report bugs" section. Otherwise, the sensor may be faulty in which case you should contact Maxim.

Yes, you can.

First, let's get minor inconsistencies out of the way first: The "straight lines" you see in my plots in the second figure are an illusion caused by large vertical scales (matching the extent of noise caused by the original algorithm). In fact, both SpO2 and HR vary in time, although not much. If you don't believe me, then click in the lower left corner to download the original image and expand it.Second, I had the same question: how can I validate that MAX30102 even works? I did a few tests to convince myself. For example, I measured my heart rate at rest and after physical exertion. As expected, the HR went up in this experiment. I also compared the sensor output to independently measured HR by a Sleeptracker device I installed not so long after this project. The numbers and...

First, let's get minor inconsistencies out of the way first: The "straight lines" you see in my plots in the second figure are an illusion caused by large vertical scales (matching the extent of noise caused by the original algorithm). In fact, both SpO2 and HR vary in time, although not much. If you don't believe me, then click in the lower left corner to download the original image and expand it.Second, I had the same question: how can I validate that MAX30102 even works? I did a few tests to convince myself. For example, I measured my heart rate at rest and after physical exertion. As expected, the HR went up in this experiment. I also compared the sensor output to independently measured HR by a Sleeptracker device I installed not so long after this project. The numbers and trends agreed, so I am a bit more confident that at least this part of measurements is working OK. I did not verify SpO2 in a similar manner, but there is a way to do it, too. Chances are that your doctor has a commercial HR/SpO2 meter. Bring your device to the next medical check up and compare the numbers. Unless you stay in your doctor's office overnight :) , there is no way to know that long time trends of both devices would agree, though.Therefore, if you still have concerns regarding your sensor, then you should address these with Maxim Integrated, Inc.

Yes, it's normal that once a while the signal quality does not meet standards and an indicator -999 is returned instead of the expected parameters. About serial plotting, I think you mean graphs posted in Step 2? Yes, that was Arduino IDE's plotter capturing live data. You must turn DEBUG on to get the raw data output.

Sorry, this is the first time I hear about "keil". I use Arduino IDE and am quite happy with it. Not knowing anything about keil indicates that I know even less about its libraries...Motion artifacts are not entirely about the sensor moving against the skin, but about moving muscles/tendons/etc. _under_ the skin. To the sensor, these are like loud sonic booms while you try recording bird songs. Hence, I am skeptical about MAXIM returning reliable data under these conditions. My setup, in particular, is almost guaranteed not to work - with a modicum of quality control the code would reject almost all signals. But not to discourage you, I admit that in my specific application I did not dedicate enough thought to combating these artifacts. Persistence is the mother of invention, ...

Sorry, this is the first time I hear about "keil". I use Arduino IDE and am quite happy with it. Not knowing anything about keil indicates that I know even less about its libraries...Motion artifacts are not entirely about the sensor moving against the skin, but about moving muscles/tendons/etc. _under_ the skin. To the sensor, these are like loud sonic booms while you try recording bird songs. Hence, I am skeptical about MAXIM returning reliable data under these conditions. My setup, in particular, is almost guaranteed not to work - with a modicum of quality control the code would reject almost all signals. But not to discourage you, I admit that in my specific application I did not dedicate enough thought to combating these artifacts. Persistence is the mother of invention, so I wish you good luck!

Thank you for the interest in my project. 1. Unfortunately, Arduino Uno is not powerful enough to execute this algorithm. I've learned it the hard way. :) But if you insist on using this platform, nonetheless, then you would have to go back to the original MAXREFDES117# code and see how they pulled it off. Basically, they've greatly sacrificed accuracy to save memory. For example, their uch_spo2_table[184] in algorithm.h is composed of uint8_t's instead of floats. I have retained some of their edits as comments in my code. IMHO, it's a losing battle not worth your time. It is much more efficient to just buy sufficiently powerful MCU.2. No, I haven't added an accelerometer. In fact, I have not touched this project since January 2018. One idea would be to use it to detect motion and hold ...

Thank you for the interest in my project. 1. Unfortunately, Arduino Uno is not powerful enough to execute this algorithm. I've learned it the hard way. :) But if you insist on using this platform, nonetheless, then you would have to go back to the original MAXREFDES117# code and see how they pulled it off. Basically, they've greatly sacrificed accuracy to save memory. For example, their uch_spo2_table[184] in algorithm.h is composed of uint8_t's instead of floats. I have retained some of their edits as comments in my code. IMHO, it's a losing battle not worth your time. It is much more efficient to just buy sufficiently powerful MCU.2. No, I haven't added an accelerometer. In fact, I have not touched this project since January 2018. One idea would be to use it to detect motion and hold sample taking until motion ceases. But in the case of your pets there may not be any periods of rest, especially considering dogs. :) The obvious idea then is to combine signal from accelerometer and SpO2 sensor to subtract motion artifacts. How? If I were to do it I would find out through experimentation...3. Our pets use hemoglobin to transport oxygen, just like us. Thus, the basic principles of the sensor operation should be satisfied. But MAXIM's sensors might be already calibrated for human skin, thus would not work on animals. Honestly, I don't know; better ask MAXIM about it.

Hi, for debugging instructions as well as some tips please follow this linkhttps://github.com/aromring/MAX30102_by_RF/blob/ma...then scroll down to "How to report bugs" section.

I wish I had powers of the Wizard of Oz, or at least those of a proficient mind reader, to be able to correctly guess what the problem is when given almost zero information about your system. Especially the one involving sensor I have never tested.Let's do this: follow this linkhttps://github.com/aromring/MAX30102_by_RF/blob/ma...then scroll down to "How to report bugs" section, OK?

Awesome work! Thank you for sharing. My oscilloscope can show frequency and duty cycle, too, but I wanted something battery operated and portable.So, ARM Cortex M3! At 72 MHz it looks even better than M0. With it, can you measure frequencies above 1 MHz? Is that the Blue Pill board you are using? Where did you buy it? Did you have to replace its D+ resistor to make it work with USB? I am guessing it does not work with Arduino IDE, does it?

Thank you for an interesting suggestion. I looked Nomorob up and learned that it (currently) works only on VoIP lines. Hence, creating the "first ring killer" would be a whole new project which would be, I suspect, quite different from this Instructable that works on POTS lines...

This should not be much of a problem, since the same reference design, MAXREFDES#117, should work with MAX30101. According to MAXIM: https://maximintegratedsupport.force.com/support/s...the only modification is an additional green LED that may need to be connected. Now, the ease of hardware design does not compare to the complexity of a new application you (probably) have in mind: monitoring HR/SpO2 during exercise, right? Wrist mount and huge motion artifacts pose significant problems and my code is not designed to deal with these. An additional accelerometer is required to compensate, at somewhat, for this additional noise. Fortunately, MAXIM offers such a kit that you may want to consider:https://datasheets.maximintegrated.com/en/ds/MAX30...https://www.maximintegrated.com/en/products...

This should not be much of a problem, since the same reference design, MAXREFDES#117, should work with MAX30101. According to MAXIM: https://maximintegratedsupport.force.com/support/s...the only modification is an additional green LED that may need to be connected. Now, the ease of hardware design does not compare to the complexity of a new application you (probably) have in mind: monitoring HR/SpO2 during exercise, right? Wrist mount and huge motion artifacts pose significant problems and my code is not designed to deal with these. An additional accelerometer is required to compensate, at somewhat, for this additional noise. Fortunately, MAXIM offers such a kit that you may want to consider:https://datasheets.maximintegrated.com/en/ds/MAX30...https://www.maximintegrated.com/en/products/sensor...

I have just finished a similar project of converting my old Sony Digital8 camcorder into a microscope. The differences are:1. I bought an extra macro lens for it (found by camera type on Amazon), which lets me achieve quite good magnifications up to 60x. Useful in detecting microscopic solder cracks. :)2. It is connected through a FireWire to my old iMac. The iMovie software nicely interfaces with it and lets me record and edit videos.3. The camera mount is motorized 9made out of an old professional CD burner), but it moves it only up and down. Seems your boom arm is better in this respect.

This question has just been resolved over e-mail.

Nice project, thank you for sharing. There seems to be only one tiny bug in the code as posted. In the main loop you have the following construct: if ((analogRead(0)>130) && (analogRead(0)<160)) { <part 1> } else if ((analogRead(0)>130) && (analogRead(0)<160)) {<part 2>}Huh? Apart from the missing last bracket, <part 2> will never execute.

On a car - that would increase car's air resistance. So, yes, you would get electrical energy (with very poor efficiency) at a cost of burning more gasoline.

Thank you. Wow, you've been very productive: 53 Instructables! However (correct me if I'm wrong), none of these involves phone hacks. Please share at least some these since I'm at the moment interested in landline phone electronics.About the ringer-off switch: Do you solemnly swear to dutifully and manually turn the ringer off every evening and back on every morning? :)Although my phone has such a switch, too, I am not that disciplined. I have better things to do than remembering about the switch all the time... This is what machines are for.

Done, in Step 3.

Very nice work. There is only one tiny snafu: your LED screen still reads "SYSTEM ON" when it's in the OFF state.

Thank you for excellent tips!

Thank you. Yes, timed switch would also work (although you wouldn't be able to make calls). There are many ways to skin a cat. ;) In fact, Amazon sells an ordinary switch + RJ11 jack combo for $15!https://www.amazon.com/Telephone-connected-Interru...Amazing what nowadays people make money on. :)

Why drive to a mailbox that is 60 feet away from home (I've seen people actually do that), when one can just walk? Why complicate things with some fasteners (I have to buy form a specialty store miles away) when two nails are so simple? (Actually, two wood screws in my case.)There are many ways to skin a cat, according to one popular saying. I chose the simplest one.For our foreign readers: 60 feet is about 20 meters. Yes, I literally saw a person opening the garage door, getting into a car, then driving these 20 meters to pick up mail, then making a U-turn and driving back to the garage... Wonders of America.

Sure, there are many ways to skin a cat, according to one popular saying. I chose the simplest one. Fasteners - these I would have to buy form a specialty store miles away. What could be simpler than just two nails?Actually, my picture hangs on two wood screws. But these are only marginally more complicated than nails :)

If your transmitter does not work - and you verified that all connections are OK - then it may be that the oscillator does not oscillate (I've found it the hard way). Desolder your antenna and try again at close distance. I've used the (advised elsewhere) quarter-wave flexible wire antenna and my oscillator worked only at super high frequencies. At lower ones it was damped down - see attached images.

This cool product from Adafruit: https://www.adafruit.com/products/292will let you display data on an LCD screen using just 2 Arduino pins.