 The great search brought to you by a different did you key? Thanks. Did you key every single week? Lady of the user powers of engineering to help you find parts that you're looking for on digikey.com lady? Oh, what is this week's great search? I'm glad you asked this one. I'm pulling it up right now So this week's great search. You'll never believe it. It's a part that's no longer available I also I want to use this sort of as an excuse to look into and research some a Class of sensors that is a near and dear to my heart, but you know, there's it's always kind of like funky learning about them, which is gas and volatile organic compound sensors So the board that we've been making we can maybe go to the computer Is the CCS 811? This is actually one of the first You know low-cost I squared C gas sensors available. There are gas sensors that are analog Let's see this where if you guess sensors, there's like this This is a traditional kind of gas sensor. It's you know an analog output You have to turn on the heater and you have to kind of do a little management and then read it What's nice is that since you know, these these sensors are quite good and they're that's what this is how you measure gases Depending on how the sensors doped It can measure, you know, I think carbon oxide and alcohols and ethanes and usually they makes a whole you know Like my nitrogen oxides, whatever they they usually can sense a whole bunch of things at once Even an analog output and they have to be calibrated But for a lot of people they just want to measure like air quality like, you know, is is their alcohol or gas in the area? This is different than carbon dioxide sensors, which are also gas sensors, but they usually use a different methodology We you know, we have a couple co2 sensors that the good ones that I really like are the scd-30 and the scd-40 scd-30 is you know an amazing gas sensor it has You know an ndir sensor Tube and it's like really well calibrated and they're very very good sensors and they're true co2 sensors Most other sensors are kind of they guess the co2 based on volatile organic compounds So So usually when you do gas you know a sensor like the You know SGP 30 for example it'll say volatile organic compounds and fe co2 effective co2 So it's it's kind of trying to guess calculate the co2 based on The volatile organic compounds it's not true, but it does it does a fairly good job But you know these are usually used at you know air quality sensors indoor and outdoor Not particulate, but for gases Also lots of scientific Use case as well, but so as I mentioned that the CCS 811 was a classic one One of the first ones people whether liked it But and we know for now we recommend the SGP 30 which is a pretty good sensor in it as an alternative It's no longer manufactured. So, you know, there is an alternative for this chip the Hold on they Recommend Substitutes they recommend the ENS 160 which I think is made by the same company Which is also a great sensor the bad news is that You're like what am I gonna get some and it's like, you know, like happy new year 2023 Which you know what and I'm happy I will when that happens I will I will probably pick some up and we'll we'll make a breakout for this and all is good But I wanted to find another gas sensor. Maybe in the meantime What like while while I wait for this to to pop into stock. So Let's go to the gas sensor Category and I'm also, you know, it's interesting. I'm not looking for a direct replacement I'm just kind of like seeing like what's what's up in this category. So it's so kind of like a little vague I'm looking for active designed only because That's where I'm at and you know, I'm not actively looking again. I have other gas sensors So it's something that's normally stocking. It doesn't have to be, you know in stock today One thing that I did notice I just sorted by you know quantity available is A bunch of CO2 sensors popped up, which is which is fine But I actually I don't I don't want CO2 sensors or again, they're they're kind of different than air quality sensors So I selected everything and then I um, I unselected carbon dioxide That got me about 200 200 things So a couple good things. So, you know the SGP 40 This is a sensor that I've used It's kind of the next jet of the SGP 30. That's a good sensor You know, you can get data out of it. It does have This kind of secondary library that you used to actually do some some calculations That's not unusual There's also apparently the SGP 41, which I didn't know about so I'm actually gonna check this out because it's like I'm assuming this is some improved version of the SGP 40 there's the SCD 40 CO2 sensor which still made it through And then there was this kind of interesting the Z mods. What's interesting is I'd heard of these But you know, I'm kind of fast in whenever I see something with 25,000 pieces in stock It did you key because it's kind of like oh, this must be like somewhat popular because they wouldn't Not stock that many of something if it wasn't and so I was kind of like Interested in looking at this a little bit more So do that in a moment and there's a couple in that family as well. And then like you see there's the Z mod 4 4 50 4 4 4 5 1 0 You know a version B version There's a couple of these There's the send 50 which actually contains an SGP 41 We covered this on IMP I earlier But really it looks like the Zeemans are kind of like taken over like there's the SGPs and there's the SCDs But but these are the most interesting so What's cool about these is they're from Renaissance who who does make sensors and such Let's see if I can load up the data sheet If not, I will I'll just go to the Okay, so it's outdoor air quality sensor platform So what's interesting about this sensor is For interfacing at least it's I squared C So that's that's kind of good. I'd like to see that like I don't like it when it's like Hey, we came with some weird ass interface. I squared C is pretty standard Not worried about being able to communicate with it the The interesting thing is it does Various measurements looks like it measures like nitrogen dioxide ozone Air quality it's got, you know, it's a mox resistant sensor like all of these are and One of the things about mox sensors I will say just because you know, I've used them a couple times is Like that analog sensor I showed you earlier, there's not a lot going on with these like They are pretty much all made the same way There's a few patents that expired probably and so people are making more of them but like the concept is the same like once you kind of dope it you get this gas resistance and You know, you you have to calibrate a little bit you have to normalize it But you pretty much are just tracking this resistance and trying to convert that into You know a semi calibrated output of what the air quality is So there's good news and bad news about that one good news is that you know technically once the patents expired people know how to make these It's it's not too difficult to just manufacture these Gas sensors the problem is is that there is in the you know as an outsider looking in it seems like because that The technology is quite simple like not simple, but it's you're just getting resistance value and then You know you you you track that and do it whatever you need to with it the firmware the stuff that actually reads that resistance and Calculates that to something is usually Either baked into the chip like the SGP 30 or for more complicated stuff. It's kind of this external Processor and it reminds me a little bit of 9-doll sensors or 6-doll sensors where you know You get accelerometer and gyro data or magnetometer data, but then you have to fusion it together And that's where intellectual property kind of comes in and becomes a firmware issue So, you know I looked into this and it's an interesting chip But but here's the deal You know the data sheets is Actually kind of empty. There's like really you know usually you open a she's like Registers and pins and bits and all that there's there's kind of nothing here They always have this like standard I squared C Diagram, and it's like if you've never heard of I squared C before like you read all about it, and they always are like hey You use you there's a stop it. It's like yeah cool, but then there's nothing after that because what you're expected to do is you down you have to submit a request to get the Firmware and the firmware comes as a binary blob that you then link in with your Application so you know they have binaries for like most popular platforms like You know arm cortex and zeros and expressive chips You don't get to see the code you you you feed it You know you feed it the data and out pops this algorithmic thing also reminds me a little bit of capacitive touch like Microchip does the same thing with Q-touch Capacitive touch is just a capacitive read. There's not there's not a lot going on There's a couple different ways of doing the waveform, but for the most part You reading capacitive data and it floats around and then it spikes and it goes down So the intellectual property is how you filter that data and they'd want to control that and so You know these days when you get Q-touch, it's not on the chip giving you raw data instead. You have to I mean you can't get through our data sometimes but they sort of hide that instead You're supposed to use this binary interface so You know, it's interesting seeing how sensors have have changed One thing I do like about Sincere in is they don't have that like when you when you use their sensors They really do pop out in I squared C whatever data you need. It's there. It's like CO2 level You read the register you do a little bit of like shifting math or whatever out pops the number With these sensors, you know, it is a little bit less expensive. You'll see it's like, you know 315 instead of 510 or whatever But in exchange what they do is they don't have a powerful processor on the chip You have to use this binary blob instead. So, you know, it's it's interesting especially for people who are used to temperature humidity sensors that are just very simplistic in their functionality to sensors that really are mostly a front end To a firmware Processing system and you need, you know, I don't think that maybe they have a library for AVR 8 bit But you know, they probably kind of require Cortex-M0 to do a lot of this calculation And it's of course under NDA. So, you know, it's interesting. I want to take a look at this chip And you know, maybe I can see if they've released a Library that I can use because it's gonna be tough for me to write a library when the firmware is under NDA but we'll We'll see what's possible. So this is the the Zmod 4510 I guess this is the new this is the new new way of this sensor. So folks gotta get used to it That's a great search