If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Spider's LED eyes

Created by Karl Wendt.

Want to join the conversation?

Video transcript

OK, so in this video we're going to connect spiders' LED eyes. Now you'll notice the LEDs have four legs. One of the legs is longer, or one of the leads is longer. So we want to bend the longer lead back. Now on the first one that we're going to put up, we're going to bend the longer lead back in such a way that we have one of the legs-- it's going to connect to pin 12. And so we want to sort of bend those legs out so that we can connect to pin 12. And then we're also going to connect next to the exposed pins, which are going to be pin seven and eight So we want to bend those legs out, and you can use the nipper pliers to trim them down just a little bit. So it'll go pin 12, pin 7, pin 8, and the long leg is bent backwards. OK, so we're going to do the same thing for this LED. And we're going to bend that long leg backwards. There we go. And then we're going to connect our legs. So the legs are going to go-- in this one, they're going to go into, looks like-- I think we're going to do pin four, three, and two. So those are digital pins four, three, and two. And it takes a little bit of doing to get in there, but we got it. OK. So those are going to be our eyes. So, I think that's right. Yeah. Line it up there. OK. All right. So once we've got the LED in place for those, we can take our resistors, and we can connect those resistors to our LEDs. Now the legs that we bent back are the negatives. They're the ones that connect to the negative part of the circuit. And so we're going to trim those down, and we're going to trim down our resistor leads just a little bit so it doesn't take up quite so much space. And then we're going to solder them together. And so when you take resistor, you want to-- I tried to twist the two around each other, and they're just too short to do that in an easy way. So what I ended up doing was-- and I was thinking maybe I could take a piece of wire and twist it, and it didn't work. So what I end up doing was grabbing a alligator clip and use the alligator clip to hold them together while-- there it goes again, it's falling. All right. Now here we go, finally got the alligator clip in place. And sit still-- there we go. Oh, it's falling again. So this can be kind of trying, but once you get the alligator clip, it should work for you. OK, so the alligator clip does two things. It holds the resistor in place, but it also allows us to absorb some heat so that we don't damage our LED. So now I'm just trimming off some of the excess there. And I will do the same for the other side of the resistor and the LED. So we'll do the same on the other eye. And now we're just trimming some heat shrink tubing and we're going to slide the heat shrink tubing up over our resistor. And that way we can protect the exposed wires from potentially shorting on another piece of metal. It's always good to make sure that those exposed wires are covered. Now, you can always take just some electrical tape and cover over it too. OK, so we've got our heat shrink tubing. We'll slide that up over the connection. And again, electrical tape works just as well. It's not quite as neat as the heat shrink, but it works just as well. OK, so now what we're going to do is, we are connecting the-- sliding the other piece of heat shrink tubing up. And then we're going to twist the two pieces together. And we'll twist those together with the wire that is coming from the negative side of our motor controller, or the negative output of the motor controller. So it's kind of tricky to get these to go together. And you can see that I actually broke the lead on the LED because I moved it around too much. So the way to fix that is to just take the resistor and-- there's already some solder on the resistor and I can hold it against the LED there and get it to hold in place. And so, that'll work. So hopefully that won't happen to you. OK, so anyway, we got the leads on the LED and we're going to twist everything together. There we go. All right, so now once those pieces are twisted together, we can solder them and make sure that joint stays solid. OK, so, we're just going to take the solder, heat it up, and make sure that it flows over the wires there. And then again, we'll trim off the rough edges and-- I realized after doing this that the heat shrink tubing then I put on the black wires is actually too small to slide over the solder that I put on. So I can't really use it to do what I wanted it to do. I wanted it to slide up over the solder. So if you do this, use a larger diameter heat shrink tubing if you're going to use that, so it can slide over that solder joint. But this actually serves as a good proof point for-- we're just using the heat gun here to shrink up the tubing. So to cover up those open leads. And then we're going to take a piece of electrical tape. And like I was saying, this kind of works as a good proof point for how the electrical tape can also cover over some exposed wire. And we'll just trim off the excess there and make sure that it's connected pretty tightly. OK, so now our LEDs are connected. And the wires are insulated, and they're in the right sockets, and everything's in the right place. Now you, again, probably want to spend some time bending the wires to get everything just right. So now we're just sliding our bottle cap eyes on. Now you want to kind of careful doing this, because you have to push the LEDs apart to get the bottle caps to go on just right. But once you got them on, you want to double check that the leads are still connected in the right pins and that nothing got pulled out. And there we go. OK, so we can see that the board is on. We're about to program it.