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

Power wires and on/off switch

In this video we show you how to switch on and off Bit-zee's electrical power. Created by Karl Wendt.

Want to join the conversation?

Video transcript

So in this video we're going to install the switch you see in the lower center of the screen. That's the on off switch for Bit-zee. And the first thing we need to do is just take the switch and push it through the hole that we drilled out and marked in a previous video. So we're going to push the switch through. And the hole's just about the same size as the thread, so it's a pretty tight fit. Takes a little wiggling to get the switch through there. So then what we're going to do is we will put the nut on the switch that will hold it in place. So we're just using our screwdriver to slide it over the end of the switch there. And we'll hand tighten that. It takes a little bit of doing. We gotta push the switch through from the underside and then just turn it a little bit. Once we've got the nut lined up and on the shaft of the switch, we can tighten it down the rest of the way with our-- It's taking it a little bit of time there. And you'll probably have a similar experience. It's tricky to get that on, especially with all the other parts that are around the bot. We're really close to the edge. But there we go, we finally got it. OK, so when you take your needle nose pliers, you can tighten it down the rest of the way. All right, so now what we're going to do is, we're going to solder our wires to the switch. And we have the wire coming from the battery. This is the positive wire coming from the battery. And we're going to cut it to the right length. And then we're going to strip the end of it. And then we're going to bend it in a U shape. And that U shape, we can wrap around the contact on our switch. So we want to try and get it in almost a perfect U. And once we have in that shape, we can put it around the contact. And once it's around the contact, we can use our needle nose pliers to crimp it in place, and make sure that it's nice and tight against that connection there. And then what we're going to do is once the wire is firmly in place, we'll get our soldering iron and we'll solder the wire to the post in the switch. So what the switch does is basically just stops the flow of electricity by disconnecting the wires. OK, so we've soldered that one on, and we'll solder another wire on to the other side of the switch. The wire that's on the other side will go directly to our motor controller. And that's where the power is going to come from. The power from our batteries is going to go to the motor controller, and the switch will allow us to break that circuit and shut the Bit-zee bot off. OK, so we've routed our power wires from underneath, up through the holes, and over to the motor controller. So now we're just stripping the wire clean there. This is our positive 12 volt wire. And it's going to go to the pin in our terminal block on the far right side. The terminal block in the center there. And we're going to just-- we've already loosened the screws, and we're going to feed the wire into the pin. And then we'll tighten the screw down on it to make sure that it doesn't come out. So that is the wire that came directly from our switch. And there's our tightening down the terminal block there. The screw in the terminal block. So we have our negative wire, which has come directly from the battery. And we are going to run that to the screw that is on the far left hand side of the terminal block. That is our ground wire. And so we've stripped the end off of that wire. And just push it in underneath the screw there, in the left side of the terminal block. And now we're going to take our 22 gauge wire, and we're going to run 22 gauge wire into the ground. This will allow us to ground other components on the board using the motor controller as our sort of junction box. So we're going to push our 22 gauge wire into the same terminal block as our 18 gauge wire from our battery. And it's not a lot of room in there, but we're going to try and slide it in. Sometimes you have to move one of the wires out of the way to get the other one in. And our needle nose pliers can help push the wires into place. And then we'll take our screwdriver again and tighten down that terminal block to make sure the wires won't come out. And then we're going to take a 22 gauge wire and run it to the center of that terminal block, which is going to provide us five volts out that we can use to power our digital camera and our Arduino and other components on our board. So we'll wire that to our bread board in the upcoming videos.