Created by Karl Wendt.
Want to join the conversation?
- why does smoke come out of this stuff?(3 votes)
- Burning of Lead.Solder is an alloy of Lead and Tin. Tin gets attached to it,while lead burns off.(2 votes)
- Is there an application in which you would solder without making the physical connection first while still expecting it to hold? Or is that a mandatory step?(2 votes)
- What are those little numbers used for on wire strippers? Are those used for the thickness of wire? I'm a total cheapskate when it comes to DIY engineering, so I've always used scissors and/or my own fingernails.(1 vote)
- Yes, those tell you what notch to use when stripping wires by the width of the wire. Don't feel bad, that's what I do to, even though I have better tools! :D(2 votes)
- how to find what resistors to use for LEDs? I have different ones.(1 vote)
- Diodes and resistors are covered here: https://www.khanacademy.org/science/electrical-engineering/ee-semiconductor-devices#ee-diode
and here: https://spinningnumbers.org/t/topic-semiconductors.html(2 votes)
- Since you tapped that yellow wire between the two batteries does it get 1.5v or 3v?(1 vote)
- Hi Shawn,
Each single pole double throw (SPDT) switch is connected to a motor. The switches are connected so that the motor will reverse when the switch (robot antenna) is activated. This allows the robot to travel forward most of the time but reverse direction when it hits something.
In this application the motor would see either 1.5 VDC or -1.5 VDC.
Please leave a comment if you have any questions.
- Can you fold the middle connection on the switch instead of the side one so you don't connect the two yellow wires?(1 vote)
- I used the parts list to buy all the supplies but i got the LED wrong and instead i got a RGB LED 5mm common annode. it has four legs instead of two and i dont know which is positive or negative. Also, i got the same resistors used in the video ...so will it work on these LEDs? please help!
heres a link to the LEDs i got
- what happens if the hot glue gets inside the battery holder from those little hole in the middle of it and the battery won't work?(1 vote)
- You would probably have to get a new battery holder. Or pick the glue out with a needle.(1 vote)
So now we've got our yellow wire that's connected to our switch here. And what we're going to do is, we're going to run this wire to the batteries back here. And the best way I've found to do this is to go ahead and remove the batteries. And let's bring the wire around-- we're going to bring it around like this-- see how long it needs to be. So we need this wire to intersect with that spring bring back there. So we can trim off this part like that, and then let's get our wire strippers here. I may take just a little bit more off. Now we've got the wire cut. And we're going to take the wire and just tuck it right behind that spring. So it's a good use for the needle-nose pliers here. All right. So that spring should snap back and pinch that wire against the outside of the-- I should say-- against the inside of the battery holder. And we could put our batteries back in. Whoa. There it goes. You can hear it running. So when we close that switch, we can turn off the power. All right. Now let's do the rest of the bot. We've still got a lot more left to put together. We're going to take another switch, and we're going to use that to turn on and off the LED eyeballs. So we'll put that together. And so here are the LEDs, and let's go ahead and wire those up. So we've got a long leg and a short leg. You can see on both LEDs. Now, the long leg is the positive leg, and LEDs are polarized, which means that the positive leg is important. You got to connect it to the positive side of the circuit, otherwise it's not going to work. The power can only flow through the LED in one direction. So what I'd like to do is bend the legs out just a little bit like that. And you can actually look inside the LED and see there's a different shape and a different size to the different legs. So the two smaller pieces are connected to the longer legs, that's the positive side, so and these are the negative sides here. And we can always double-check that by straightening the legs back out again if we want to just get a sense for which one's longer. And the longer leg is again connected to that littler piece of material on the inside So let's go like that and like that. So let's make this center positive. And we can do that just by twisting these wires together, or these legs together, like this. Now, in order for the LEDs to function properly, they have to have resistors. We need resistors, because otherwise the LEDs will draw too much current from the batteries and they'll burn out. So we're going to take a resistor and wind it around the negative leg. The resistors can technically go on the positive or the negative. There we go. And we'll do the same thing on this side here. All right. So we've got a lot of pieces that are connected there. And now remember, we've got-- oh, looks like we've got our negative from our battery is here, and it looks like the positive may have come off. So we can add that back. Let's go ahead and put our antennas on. So we're going to bend our paper clips out. We'll do that in-- actually, let's do the antennas in just a second. Let's finish the LED eyes first. So we're going to take the red wire, and that's going to be the positive or the center wire. And you just need to trim off just a little bit. There we go. We're twisting that wire around the center, because that's going to be the positive. And so the negative wires will connect to the negative. So this switch is going to let us turn our LED allies on and off. But we have a disconnected wire here. It looks like we need to reconnect the positive to that there. And we don't really need it to be quite this long, so we're going to trim it down. So we need to do a red wire there, and we don't have it right now so we're going to reconnect it. And we do have a little stub that's sticking up, so we can just-- oh. You can hear it's bumping the switches and it's turning on and off. So once we've got the red wire there, we can go ahead and solder that in place. And you can see it looks like we've got a pretty good connection to our positive. So in order for this switch to turn on and off our LED eyes-- zoom out a little bit here. There we go. In order for this switch to turn on and off our LED eyes, we need to connect it from the negative through this to the positive. And before we do that, let's go ahead and put some solder on the connections here to make sure that they don't come apart on our LEDs. And you can actually see the solder wick up and down between the wires. So we need to connect another wire here to these. So let's see, let's make that another-- we'll make that a white wire. And let's take off just a little bit. There we go. And we're going to twist the two tails of this together like this, of the resistors together there. And it's important that the wires stay separated, so we may put some tape over that, some electrical tape here to just keep everything separate, because obviously if the positive and the negative touch it's going to short. So let's go ahead and see where we can wire this up. There we go. And we want to make sure we have that solid, physical connection before we connect it with solder. All right. Here we go. There it goes.