 Did you key and ate a fruit bring you? The s stands for Sensors, that's right. It's from sincere in sincere on the sensor company Also sounds like a you know, like a marble character sincere on yeah has all the senses from planet sensor. That's right Try to story what happened to the planet sensor. I was in Syria is actually a Spin-off from ETH. I think they're in that Switzerland and they have some offices around the world and they make great sensors We love their temperature and humidity sensors the sht series They've been doing this for quite a while and recently they branched. Well, they've also done carbon dioxide sensors We also have part particulate sensors But they branch off into doing gas sensors. I really like their gas sensors So what I saw this new gas sensor from sincere in on did you key calm? I was like sweet because I'll make a break out for it and like I'll also use that an excuse to like make a nine MPI So this week's iron API is the SGP 40 Yeah, yeah. All right, let's show okay all of it. This is it. So it's a little surface mount chip and What it does is it can measure volatile organic compounds and does that with an MOX sensor a mock sensor It's a metal oxide. So how does that work? Well, you know Sensors have different basically sensors are there's not only so many different ways you can measure something and Resistance and capacitance are kind of the most popular like either you can somehow turn your thing You're measuring into resistor where you can like turn it into like a capacitor Or maybe you can like turn it into a voltage in this case Well, you have is a piece of silicon and like what you're seeing here is actually like very small There's a hot plate, but the hot plate is actually just like a you know It's actually the PCB material that has like a resistor just like you have on like a 3d printer It's a gigantic resistor on top of it You have this MOX layer as metal oxide Semiconductor layer that's on top and it's particularly designed so it absorbs hydrocarbons and that changes the resistance and then you can measure the resistance Across the sensors is all kind of like embedded MEMS technology. So it's kind of good stuff The previous sensor that we have been stocking and really like is the SGP 30 and this is also a gas sensor that does volatile organic compounds and Can kind of mimic carbon dioxide measurements from that it can kind of back calculate them So the SGP 30 is like the previous version. This one's a little bit different You know as I played with it today, I want to drive where I kind of learned a little bit of the differences They're basically both gas sensors But this one kind of just pops out volatile organic compound measurement and Effective carbon dioxide whereas this new sensor gives you the raw Metal oxide sensor reading and then it's calibrated But it's what's the same between chips, but you get the raw reading and then you would use their library to calculate You know basically air quality so What I like about this is that most metal oxide Gas sensors, you know, you saw that there was this hot plate So the hot plate is like a resistor and you have to like control that turn on and off and it's like, you know can draw You know a couple hundred milliamps or a hundred milliamps or so and Then you have to read the resistance and you do that with an op amp or you do that With a resistor divider What I like about the SGP series is it's got this very basic and very easy to use I squared C Interface and the I squared C isn't that weird I always rise a little crazy when some companies they they do really unusual I squared C, but You know, this one is actually pretty simple. You send in these two bytes with the command and it returns back You know a couple bytes with the data and there's only three commands. So you don't have to think too hard And there's a CRC with the bike code Sorry the data that comes back so you can calculate the CRC value to make sure you got the right data But it's pretty simple. You just extend two bytes. We'll see three bytes and the data you get back is this raw reading from the The resistance not the exact resistance that it's a calibrated reading that tells you Approximately what the resistance is like to a calibrated amount and then they haven't yet at the time of this video would lease the library for converting that into Volatile organic compound readings, but hopefully it will be released soon And I hope they do it in a permissive way so that you can easily use it in various libraries With different chip sets So yeah, this is basically how they expect to use it. You would take the SGP 40 You'd also grab one of their sht humidity sensors. You use the humidity sensor to like optimize like you want to kind of Make sure that you don't have humidity affecting the measurement because you know humidity normally does make there's a change a little bit So for the best precision, you would have a humidity sensor as well. You plug that into the driver and then out pops the VOC index and I'll try out the code when it arrives But apparently it gives you a number between like zero and 500 and so it's designed to be a very simple way of Doing air quality measurements So most people talk about air quality And I kind of this graphic because it's very handy So air quality has like four different components and this is the one on the left This is the VOC the volatile organic compounds like ethanol's and you know other gases And I'll show you even alcohol worked quite well At the top there's CO2 And sincerity also has a CO2 sensor. I think it's called the SCD 30 Check that out. It's a really great true CO2 sensor A lot of sensors that are surface mount and low-cost they sort of they're effective CO2 But they do have a true CO2 sensor As we mentioned their relative humidity and temperature sensor series the SHT series is great. I love the SHT 3x series the 30 31 and 35 different Accuracies and then PM 2.5 which will give you like like particulate like chunks of stuff like dust in the air Which is what you have to deal with when there's forest fires I was in the news people know about that now and we're everyone buying masks That was one of the criteria is the PM 2.5 the same thing as N95 all sorts of stuff Yeah, so now suddenly everyone's an expert at this so So you can pick this up. It's available of course on digikey and we have the number one six four SGP four zero D are four C T and D That's my exam of the week and digikey.com for slash short for slash ZW Z JQ B and you can of course just search for SGP 40 on this key and check at the SG 30. So they're not exactly the same. They're a little bit different But they're they're both air quality sensors And I think this one when you add their library I think it'll be able to like give you more information when you but you have to do that like my controller based Processing so next up because I did get a driver working. I have here My Qt pie board. So I've got I just USB C power connected to a quick connector For stomach Qt. I reworked one of my SGP 30 boards This is actually 30, but it's actually SGP 40 and then I've got the OLED displaying this number This is like the 16-bit number. So then you're like, well, how do you how do you have licked a? a Response from a sensor that's for air quality. I don't want to reduce the air quality here But you can do a great job with alcohol because alcohol is you know an ethanol so you can Take the cork from this very nice liquor and You put it near the sensor and you'll see the number is dropping. So it was 27,000 now it's 20,000 If I get it really close I may be can get it to drop even more once a while in the past if there was alcohol around me I would drop Yeah, like that. So your distance drops just like people in their distance drops when alcohol is involved So you see that you know when I really saturated it the resistance goes down and then when I remove it It slowly crawls up and one of the things that they really tout about the SGP 40 is you're gonna get similar performance from Chip so you don't have the MLX sensors gas sensors are known for their variability you need to calibrate them These apparently have a lot less variability from chip to chip So you don't have to worry about the auto calibration procedures that you'll have to do and also They don't degrade with time. It's another thing that happens to gas sensors They degrade over time and the sensor has to be replaced because it gets tarnished basically or oxidized But the process they're using for these sensors apparently last they say up to 10 years So, yeah, so you see it's already back up to about 25,000. So a great Weight before you and that is this week's on MPI. Thank you