 The great search brought you by digikey thanks to key and a fruit every single week lady to use their powers of engineering to find the Things that you need that's right you on digikey.com lady to what is the great search this week? Okay, so this week I'm experimenting with ultrasonic sensors I wanted to make a stem aboard with a single ultrasonic transceiver on it that can be used for distant sensing and so let's go to The computer because I'll show you what people got and I'll show you what I want okay, so a Lot of times when people think about ultrasonic distance sensors they think of something like this It has a transmitter. It has a receiver it sends You know a pulse out and then it gets the bounce back ultrasonic signal on the other one So like usually this is easy here And then this is our transmit receive and on the back there's a little chip in this case It's the RCW all it's an off-the-shelf all-in-one chip Which is great, but there are some situations where you might want something slightly different one You know you're kind of stuck with whatever transceivers they picked here So maybe the range and the cone isn't what exactly you want Second this chip uses the you know pulse trigger technique and that's all good and everything but You know if you want something like I squared C It's gonna be you know tough to get out of this. There's an I squared C mode here, but it's not a great I squared C mode So it would be really cool if we could basically do the the ultrasonic transmit receive All on one microcontroller because there's no reason why like an everyday microcontroller Couldn't do that kind of sensing and second. I do want to see if I can make it use a single transceiver It's a little bit more challenging because you have to kind of flip around some pins, but you know we I've seen Ultrasonic sensors that have only one Transceiver like the max botics and I know that they they work quite well And we've stocked these for easily a decade. So You know, I know it's possible. I know you don't need like the very latest technology that they may have an ASIC I'll not I'm not sure but you know looking around it seems like there is some code and examples as long as your Trent as long as your transmitter is okay for transceiving You know it can get out of transmit mode and start listening to signals on receive You know, there's no real reason why you can't do it with one, you know, they only the on the other hand I know of a backup, you know, if I really absolutely need to I always have the This style as a backup, you know, this is like a very simple schematic on the back, you know, there's really It's just like a one SOIC chip. So, you know, tacking on a microcontroller to do I squared C or You know, some of the conversion wouldn't be wouldn't be too hard. You have a little backpack that goes on this No biggie basically. So I always have a backup, but I thought it would be interesting to explore and you know, I found You know, there's an app note here on using a pic in this case it does, you know, one receiver and one transmitter, but Again, I think that, you know, you can switch between the two Modes You know, here's from Carrie Wong. It says 10 years ago an example of also using a transmitter receiver and doing it with a microcontroller, so not using a specialty chip In this case, they just used an H bridge so they could get like a differential strong differential signal and then they used a Dual op amp to do some band pass filtering and then you know some chunky magnification looks like two gain stages with some filtration at the same time to read the signal in and Turn it, you know, read it on Arduino and then they made their own Ultrasonic sensor so there's like, oh, yeah, you know, we got this working Not too badly and then also, you know, I found this cool teardown Similar there's, you know, a transmitter and then there's a receiver with it a dual gain amplifier with a little bit of filtering in it and This one uses a single Transceiver as well. So it it switches between Transmit and receive mode. So, you know, I'm I'm thinking that this design isn't too impossible So what I need to find now is Go to digiki and find myself a transceiver find myself this 40 kilohertz Ultrasonic transmitter slash receiver element that then I can purchase and Experiment with and I know that I can, you know, get a good quality reliable transceiver from digiki To verify my designs like if I buy something on eBay, it's like who knows what, you know, you buy components It's like they say the transceiver, but it's not they just took a transmitter and then like just scratched off the tee or something I don't do that. I want to get something that's like the real deal so let's go to digiki and I'm going to look for ultrasonic and Then I'll look for that. I don't know if it's it's not actually called a transceiver necessarily So notice that there's a couple if you search for ultrasonic you can of course just get the Sensors themselves. So this is like, you know, they're ready to go Sensors and you can see here. Here's another example. This is a single Ultrasonic You know one trans transceiver transmit and receive in one. I like the look of these They're like they're kind of small. I feel like you can fit them in more places But there's a lot of examples of you know, you can see here. There's some Two elements. This is short range. So maybe, you know, if you want because of this is echo effect that occurs Having two elements might be better for for short range sensing But Yeah Give me it could be good. All right, so we've got that But we don't want the full proximity sensor. What we want is the raw module itself like the You know, I don't want the board. I want like the this thing the the actual like black spherical component Your tubular component Okay, so here I Got when I got here, it's actually kind of mixed, you know, there's a bunch of ready to go ultrasonic sensors and Individual elements as well. So that's something, you know, that got a little bit mixed up So what I did here because you know, you can you know, there's this parallax sensor No, this was made in 2010 these are they've been making parallel perhaps they're making ultrasonic sensors for a while But what I want is like this. So what I ended up doing This is unusual, but I actually filtered by manufacturer So like I took out like a to fruit me because I know that we don't sell that Module and I took out parallax because it's like they're selling the ping sensor And I took out spark fun and I took out Max botics because they're reselling the max botic sensors and when I did that I actually got rid of like a lot of parts and I got to only like the individual components Which is what I want like I want I want this stuff the raw stuff So Now that I've got that now I can do my standard filtering. So I'm gonna look for active and for type You know, I want transmitter and receiver and I don't know what this dash is So I'm just include it because no harm and then yeah, I've got a whole bunch of options I mean, I think a lot of these are like DFR about these are modules as well. So I think I will Yeah, so there's they have a bunch of like ultrasonic Sensor. So what I'll do is I will likewise filter Filter out DFR bot. Okay. So now we've got 25 Okay, actually have a shot now being able to review these So there's not a ton and like I some of these are like on wires and some of them were kind of chunky so Let's go by price and I got some good options here. So it looks like there's some metal ones. All these are called transceiver So that's really good And then I want about 40 kilohertz These are all about 40 kilohertz. Oh, not that a lot of them, you know, they're rated for extremely high voltages Like you're you know, you're expected to drive these at easily 1020 volts. So oftentimes designs will have doublers Like voltage doublers like a max 232 to get the voltage much higher We have a boost converter and then use that to drive the transceiver But all these look good and I think, you know, all of these ones up here looked pretty reasonable the the coey ones and I looked at the I think the 18 and 15 is the diameter. So I looked at the data sheets And You know, basically they tell you How far they can do Ultrasonic sensing. So this says 15 meters Um, so that's cool And then let's look at this one This one's 18 meters. So it's I think there's like a trade-off. It's like how sensitive versus Um, the range and also how big it is. So this one I think is Oh, I see the 18 is the 18 meters. Okay, so 15 is 15 meters So you're gonna pay a little bit more for More range, but that said Um, I kind of went with the one that they had the most stock of to start just to get a couple samples of Um, because I felt like this was promising and here's another thing. I'm actually kind of tempted to contact CUI and just say like do you have an eval board or an eval schematic? um, that I can borrow take a look at because for that, um amplification filter section with the the dual op amp They might have something that they're like, hey, we've already tuned it for this transceiver. And so we're going to know like How loud the signal is going to be or like sorry the voltage and then also um, what like what resonance it's going to like being it so I gonna order some of these. It's interesting. These are kind of recent. These only made A few years ago or at least this data. She was only made a few years ago in 2020 Um, but this looks like perfect. Otherwise, it's a good it's exactly what it should look like And it's designed to be a transmitter receiver and you know lands of 40 kilohertz um, and it's designed for distant sensing up to 18 meters. So Uh, check it out. I mean, I'm going to see if I can get this thing working Based on those online schematics and see if I can make it the cutest little transceiver in the world All right, and that is the great search