 Great search is brought to you by DigiKey. Thank you DigiKey for helping make the great search happen every single week. Lady Edie uses her powers of engineering and more to navigate the DigiKey site, to search for all the parts and components, and we take requests and speak enough. Sweetie, we have two requests, so we're going to get to do with this one this week and one next week. So somebody posted on the forums and they asked, okay, they want a latching power relay like the Omron G6C. So basically they said, look, they want a power latching relay feather wing. This is what we've got now. This is the power relay feather wing. And the power relay feather wing has a big sugar cube Omron relay. And you know, you turn the relay on and it moves the latch, not the latch, the throw over to the other pole. And so the middle pad of this terminal block connects to the one or the other from the sides, either the left side or the right side. And that is a really nice, you know, high voltage friendly and we have a cutout and it can handle pretty high voltages and high currents. So this is 1200 watts, so it can do, you know, five, ten amps of current for like a small appliance. Like it could definitely handle a small toaster oven or lamps, you know, fans, lamp, you know, sort of think like small heaters, televisions, etc. Appliances, things around your house that use wall power, motors, etc. So this feather wing though, the relay that it uses is a power relay. But you have to hold the pin high to keep it connected. So basically, like if you want it to only turn on when you turn the relay on, what you want the contacts to close to create the circuit when the relay is on, you have to hold that pin high, which does use a lot of current. And the alternative to a normal relay is a latching relay. And a latching relay, you don't have to hold the pin high or energize the relay. You just toggle it and it sort of like clicks and latches the relay into one position and you move another pin and it latches the relay the other direction. And we do have a latching relay feather wing, but it's only this mini style. So you see there's a latching and non-latching. So this one is latching and it takes two pins, a set and unset pin. But this relay is much smaller than a telecom relay, so it's only like maybe half an amp. Not very high power, it takes 70 watts or so compared to the other one, which is over 1200 watts. So this person had a good point though. I was like, oh yeah, you know, I never made a latching power feather wing. I should do that. I should go didgy key and search for that because finding a latching relay that'll fit on a feather is not necessarily easy. A lot of relays are really big. We want something that's really slim. So let's go to the overhead real fast and I'll show that. So this is I happened to have at home a relay feather wing. So you can see it's kind of chunky. And this is about 15 and a half millimeters by 21 and a half millimeters by about 18 millimeters. And it's solid onto this feather wing. It's not taking up all the space. I do have a little bit of room over here, so it can be a little longer. But I really don't want it any wider because you see it's already it's kind of gay near the edges of the feather. I want it to be narrow. So let's make sure that we get one that's narrow enough that it fits onto the feather. It can be a little tall. I mean, this is it's a sugar cube with chunky. But I don't want it to I don't want it to be longer than the feather wider than the feather wing. All right, so let's go to the computer and I'll I'll do the searching. OK, so let's search for relay to start. And you're like, why don't you search for latching? Because if it's latching and not latching, I'd rather just go to the relay section and then search. So OK, so there's power relays and signal relays. So signal relays again, like telecom relays, they're less expensive. They're smaller. They're often surface mount. But they don't do high power. They do less than two amps. Now granted that two amps is, you know, is it at low voltage or high voltage? Either way, I definitely want it to be five to 10 amps of current at 240 volts AC. So I definitely don't want the signal. I want the power relay. There's also solid state relays, which are going to be they're different. I think they're not going to be latching. They work in a different way and they don't work for DC voltage. So I want to make sure this works for AC or DC. I want the mechanical relay. So let's go to the power relay section. So I have 22,000 relays. Let's go with active. So I want only ones that are going to make a product out of this. Now, normally it would only click in stock. But because there's been so many shortages of components, I'm going to click normally stocking instead. Because I want to make sure there could be good ones that are just not in stock right now, but they will be in a couple of weeks or maybe a month or two. I want to find what's the best possible thing because relays are very specific. They're not like some silicon components where it's like, well, the op amp or the transistor, I'll just find whatever it is that's good enough. I really want to pick the one I pick. The mechanical shape is going to be very specific and it's not going to be easy to go to a different one. So I really kind of got to pick one and be done with it. Okay, so next up, the next thing that's really important is the coil voltage. So because it's going to be on a feather wing, it has to be powerable from feathers. And feathers are three volt logic. They get five volt power from USB, but they can also run off of a battery. And in fact, this person who posted said they want to run off of a battery, which is why they wanted to be latching. And the batteries, they're four volts or so, but really, they can start dipping down to 3.5. So I don't want to require a five volt relay. I want it to be less than that. I think three volts or less to even 4.5 volts is a bit high. Because remember, lipo batteries, 4.2 volts is about as high as they get. And there's no, I don't want to risk it. I mean, I want to make sure that if they want the relay to activate or deactivate, that they can do so. So the coil voltage, I'm going to select 2.2 to 3 volts. And you'll see this really reduces the number right now. I think I have like six, we went from 12,000 or sorry, 20,000 to 6,000 to now it's only going to be 89 options. Okay, so next up, there's a couple of things like coil insulation or must operate voltage, but none of these are important. So there's now two kind of coil types, right? Because this is why are we here? We're here for the latching. So the next question is, do you want single coil or double coil? And actually didn't know the difference between double coil and single coil until I had to go look for this because it usually didn't matter. But when I picked, double coil is a little simpler to use. Double coil is you have two pins, and when one goes high, the relay latches one way, and the other pin goes high, it latches the other way, right? So each pin when you toggle it high. However, what I noticed was is that I had a lot fewer options with double coil and single coil. There's more single coil options because I think the mechanical construction is a little simpler. So I will select both, but I will note that single coil is easier and I'll show you how we're actually going to use it when we get to use it. Okay, so the next step is do you want single pole, single throw? Not really, single pole, single throw means really either connected or not connected. I like to have it be normally open, normally closed if you have two options. So I'm going to pick the SPDTs and the DPDTs. So you can have something open or close and they pick which way they want it. Surface mat or through hole, I don't think I'm going to find it a surface mat one, but I'll leave it all selected. Okay, so going down here, I'm going to view the prices at 500 pieces. Just because one relay is usually $10 and they quickly go down in price, so I want to compare them at a reasonable price. So yeah, there's a couple of good options. So this one is sneaky, so there's this telecom relay and you're like, wow, this is surface mat, it looks pretty small, and there's 10,000 stock, this looks great. The problem is, is that I actually went and looked at the data sheet, which hopefully will load. Oh no, data sheet, you can do it. Okay, so when you look at the data sheets, even though it's in the power relay section, if you look at the load, the current is 5 amps max, but only at low DC voltages. And as you get higher, it definitely goes down. And so I think it doesn't seem to, it said it was okay for AC, which is probably going to be the same as DC, but basically, it's a single relay, it's not a power relay. So even though it's in this category, it was very attractive looking. So the next one I looked at was the Omron one. And the reason is, it's like, well, I know Omron ones and they look pretty good. It's inexpensive, it's not in stock right now, but I know that they're normally in stock. I also looked at this TE one, although the pricing is significant, like this one's 250, and then they get to $4 quite quickly. And I do have to keep it price sensitive. So let's look at this relay. So this is a high switching current general purpose latching relay, that's kind of what I want. So this one, oh, this is a confusing day sheet. Okay, so for this one, the thing I noticed was for the single winding latching type, you'll see it goes down to 3 volts rated, 200 milliamps. But if you are 5 volts, hold on, this is the trickiest day sheet. Sorry, this day sheet has this weird page that kind of flips it. Okay, let me move this over. Okay, you see it. Great. So for the double latching type over here, you'll notice that it doesn't have a rating voltage lower than 5 volts. And that's why I was having this issue where I was like, oh, I want the double coil because it's easier to deal with. However, when I did double coil, I didn't get to find this particular relay because only the single coil version has 3 volt activation. So the difference in how you use it, and let's, again, hold on, go to, yeah. See this day sheet, it's like wide. It's kind of an interesting day sheet. So this is the single, this is a single coil relay. This is what it looks like. So you see there's one coil and there's one pin. And then when one pin is high and one is low, it pulls the armature one way. And then when you invert it so the other pin is high and one pin is high and the other is low, the armature moves the other way. Why does this matter? So normally, if you have a double coil latching relay, of course you have to put a lot of current through the coil. So you're going to have two transistors, one for each coil, to help you drive that current through the coil. So it's basically like a solenoid. You have two power transistors of some sort, enough that can pass 200 or 300 milliamps. And then you can turn each one high or low using that power transistor. With a single coil relay, you have to treat this like a motor. It's kind of like a bi-directional motor. So you actually need an H-bridge for this because you need to pull a lot of current through one way and then pull a lot of current the other way. It's basically an H-bridge, a little more annoying because now you need four transistors instead of two. However, it's a $1.50 lesson price and there's more options available. So I'm probably going to do that. It's not a big deal. You can make an H-bridge out of four transistors. It doesn't have to be a great H-bridge because it doesn't have to stay on for a very long time. It doesn't have to be on long enough to latch the relay one way or the other so it can be like a kind of like, you don't have to use the best transistors in the world. It doesn't have to be good enough. And then you just have to have four diodes as well as flyback diodes for this. But basically you have to treat it like a motor. This is the single-pull single-throw version and oh man, this data sheet, man. It's kind of weird. And this is the double-pull double-throw. So this is the one I'm actually going to get. And you can do, I'm just going to double up. You know, it has multiple pins for some reason. I don't know why they're actually inside. It's only one relay. So I don't know, twice as much current goes through. Maybe I don't know. And then again, this sneaky, I don't know, like this data sheet. Okay. And over here you can see the, if it's a single double coil, you see how it works inside. There's actually, it is one coil, but it's doubled up. And then you have to kind of like pull it from the middle. And that's why I guess you can't use it with three volts. This is five volts only. But I need three volts. So, you know, my decisions have kind of been made for me. That's okay. This is a pretty good relay. Next step, you know, now that we've decided, okay, we're going to do the H bridge. We're going to do the single coil. Let's look at the mechanics. This data sheet. Okay. Well, these are all mechanically the same size. So this is 29 by 12.7 by 15.5. So let's go to the overhead again real fast and we'll see how this compares. So length wise, this one is 22 or so. And the one we're picking is about 29. So I like to sort of measure it. So it's going to be a little bit longer, but not, you know, it's not longer than the feather. So that's fine. And then for width, it's going to be 12.7. And this is 15.5. So it's going to be thinner. It's going to be kind of significantly thinner. It's going to be a little thinner. It's going to be skinny like that. And then for height, it's 15.5 millimeters, which is, I'll just do it here and you'll just have to trust me. So that's about 15.5. So it's actually a little bit shorter as well. So it's basically going to be a longer, thinner, shorter version of this relay, but it'll definitely fit on the feather wing. So I'm going to order some of these samples. Since the three-volt one isn't in stock, I'm probably going to pick up like the six-volt one and then I'll just like jury rig it to get it tested and trying it out. I'll feed it six volts and then get the mechanics set up and then I'll be able to convert it to the three-volt version when I finish and then do the testing before I release the product. So the winner of this week's The Great Search is this Omron G5R-LU-1E DC3. You're the winner of this week's Great Search. Thank you.