 on MPI. This week's Ion MPI brought to you by DigiKey Native Fruit is AM Osram. AMS Osram. AMS purchased Osram so they're now a combo company. You get two for one. Lots of optoelectronics and this week the Ion MPI is optoelectronics based. It is the, hold on let me get the exact part number, AS7038RB which is an all-in-one PPG which is like phylozomia graph, it's pulse oximetry and ECG and temperature, skin temperature and GSR sensors. Kind of this all-in-one amazing combo sensor. It also looks so cool with this exposed sensing element and it's designed for, you know, heart rate watches or workout bands, you know the ones that like usually they have accelerometer to, sorry can you go back one, I didn't mean to tap you, you know for sensors that usually accelerometer to do like how many steps you've taken but they also usually can measure your heart rate, they can measure your pulse oximetry, they can measure your skin temperature, they can measure how much you're sweating by using GSR. So this is a vital sign sensor so what's neat is that you know usually you have those four sensors to be done differently, you know separately, you know usually especially ECG or EKG is done separately than pulse ox but this actually combines the two, you still need to have the contacts for the ECG but the computation and the data capture is done on the sensor which then can filter everything and give you I2C data out. So the thing that it does that you're most familiar with probably is pulse oximetry. You know by shining light through your skin it can determine how much oxidation you're getting of your blood with a little bit of calibration, you can calculate your SP02 which is really important. A lot of people have pulse oxes because if you have COPD which is a very common disease in America or if you are COVID-19 positive and you know you have a bad reaction or you have some immune compromise and so your cardiovascular system is affected, your pulse ox is kind of the first thing that will tell you that you're in trouble. And this is what it looks like, it's you know the PPG is not quite the same as heart rate, I mean you can kind of determine heart rate from it but it's not quite ECG, ECG especially if you're using electrodes you'll get like a really good electrical signal of the heart which will show you all the different waves. What you'll get out of PPG is just you know how much oxygen is in your blood and are you getting a good pulse rate. So it's it's you're definitely ECG and pulse ox PPG are very similar but they're they're used for different things. This is a gift that I saw from Wikipedia and it's just awesome because it actually shows the light. That light isn't flashing that's just like your your blood changing how much red light it lets through and then you you know it's it's very extreme in this photo and then you can see how that is converted and and red and then turn into heart rate and pulse oxymetry data. So this is the there's a couple models this is the 7038 GB and you can see on the left top left there's the ECG amplifier so you'll do need to have the in positive in negative and in reference there's you know some people can use their fingers or you can of course use electrodes will get you the best signal. There's the LDO there is the optical front end that's connected to four photo dives in the center there's green clear and red which you know you you read that data and you can use that to do various calculations. There's also a generic ADC that can be used with an external NTC thermistor to do temperature sensing and then the other analog front end can be used for G SR which is used you know it's sort of like it's galvanic scheme response sort of tells you like how excited or active the person is it's like an arousal state which sounds much more exciting than it is it's kind of like how active and how aware you are of your surroundings if your surprise usually spikes up and if you're bored usually is quite low. So it can it can keep track of your you know attention span. So this you know all this comes into you know a filtering system and digital control sequencer that you can see connects over I squared C with the interrupt pin so it's a very lightweight sensor it does a lot of work for you and then just gives you the basics over I squared C which is nice. There's also another oh sorry this is the hookup diagram so you'll notice that you do need a couple passives and this version of the chip is very small it does not include the emitter LEDs which do need to be you know a little bit far away from the sensor so they're not in chip because you don't want to get inner reflections so normally you would have like a mechanical barrier between the LEDs and if you look at your smartwatch on the bottom there's the sensor in the middle and then the LEDs there's some plastic or epoxy that keeps them from lighting you know the this from the light bouncing within the sensor element. You can also see the GSR electrodes on the right and the NTC using the those extra ADC inputs and then the ECG electrodes on the left and then you know connected to a host processor which then usually has accelerometer and you know charge stuff but it pretty much is all you need other than the accelerometer it's all you need to make like a smartwatch health watch. The other model which I kind of dug it's not the INMPI but it's it's like little sister is the AS 7030B and this one is physically larger I think it has the same 7038GB inside of it but it's like got this plastic case around it which you can see is isolating that inner sensor and then you see those three bumps those are LEDs so it's a little bit larger but it basically looks like it's got the same sensor in the middle and then it's got the LED emitter so this is more of like all in one so I thought it was to be handy if you're interested in the sensor you might be interested in this variant. That center is the like big-ass photo diode so there's a lot of green there's a little bit of white and red green is the most common color that's detected because your blood's red and so like you know green filters through quite well. This is the optical front end so what I thought was kind of nice is you know I remember like making you know kind of pulse ox and ECG types of circuits in class and because I was learning analog in class it was like you did this all in analog and ironically it's much easier to filter a lot of these signals in analog because they're analog signals you can do a low pass you can do a band pass a high pass whatever offset reduction but this you know what is nice is that or rather what's frustrating is if you don't do the filtering in analog it's or the amplification filtering analog it's a real pain on the digital mic controller side because the signals are very small they're quite noisy you know as people move and they're they're working out or they're walking or they're not you know they're holding their finger tightly or not or they have a tan or they have darker skin it can all be affected but thankfully all of the switches and filters you might want are built in then you can configure them to get the you know based on your design and the person that you're measuring their biosignals you can get a really good signal out and this is the signal path for this kind of I kind of like this they show like here's the different filters you can do so there's the offset reduction there's the low pass and there's the amplification so what's nice is that you can filter out the noise and then amplify the signal up so you're not amplifying the noise and then having you know getting any lacing from that and then this is the ECG circuit which is a little bit simpler because it's like everyone's heart is kind of the same rate so it's like the band pass is like hey your heart rate is probably going to be around this so you know if it's over you know if the signal is over a certain frequency you know what you want what you don't want so this is doesn't have as many switches with it it looks like there's also an eval board for this entire family the as 70 30 family you can see the sensor in the top right the three golden pads or the ECG pads and you can actually put your fingers on them and you can you can get a fairly good not you know maybe medically accurate ECG signal and then left our favorite feather it's a particle argon which I really like that dev boards are starting to be feather compatible so I might pick one up and try using it just with a you know feather m4 or something or p2040 but this is a nice iot board which has of course wifi and bluetooth ready to go and they have some handy software I like that you know look it's windows only and you have to use the eval board but it shows you the graphs the signal it's really good if you want to tune like the hundreds of little tweaks that you can make to the design you can get it to a really good state so you can launch with a with a good stable signal what I thought was nice is they give you some values to start with and you know a lot of people remember we chatted about the paper that came out during COVID that was like hey a lot of pulse oxes aren't tuned for dark skin they'll actually give you incorrect readings so what's nice is that they show you hey based on your finger wrist what values should start with and that'll help get more correct values available on digi key and it's when we say when we say available we mean like you can get it you can actually get it it's in stock so this the sensor is available the family is available there's also val boards I thought it was kind of cool I like these all-in-one sensors great if you're making if you're making some like buyer reading project the sensor will kind of do everything for you yeah someone said you could make a alarm that posts on the facebook to let everyone that their heart stopped yeah good yes that's very morbid but you absolutely could do that yeah could have it do it if then this said just turn turn off the page you know yeah done I'm now I'm now are you dead log off of twitter you know nothing really dies it just you know it's not crater just right it just goes to another form yeah gotta look at that way um okay and do you want to show anything on the overhead or are we done with ion opi well I thought I could show the sensor real fast okay it's quite small but I could that is small I could show it so that's this sensor it's so tiny oh shoot uh yeah so it's got the you can see the the green element that's the sensor on the top and then on the bottom you've got uh all the pads for all the GPIO so that's that's the sensor the 7030 from ams all right that's an MPI