- 3rd graders build robots at Santa Rita Elementary School
- SPDT switch
- Spout's sliding SPDT switch
- Spout lights
- Spout motor
- Spout battery configuration and polarization
- Spout's reversing circuit and final assembly
- Spout circuit
- Rotary switched spout circuit
Created by Karl Wendt.
Want to join the conversation?
- What does the switch do to help the robot?Does it turn it on and off?(5 votes)
- At0:35, why do you use this kind of switch?(2 votes)
- Hi Lancelot,
There are thousand's of application that can use the "single pole double throw" switch. Here are a few links to get you started:
All right, so this is our single pole double throw sliding switch. It's not a single pole double throw lever switch, like the switch we just took apart. It's a little different. So it's got a plastic slider here, which goes back and forth. And it connects the power between this contact and this contact or between this contact and this contact. So this is called a single pole double throw because there's one pole in the center and there's two throws on either side. So let's go ahead and take it apart and see what it's made out of and how it's made. The outer housing is actually kind of ingenious. It's stamped steel that's nickel plated. And what they've done is instead of using screws or glue, they've just basically taken a flat sheet of steel and bent it around a bunch of times to hold everything together and create a nice housing. This can be put on a component circuit board and soldered in place to turn things on and off. And it can be used on our Spout bot, of course, to turn the LEDs on and off and the motors on and off. So let's go ahead and take it apart. The first thing we need to do is these little tiny tabs here, we're going to try and bend those out of the way. And I'm going to use another pliers here because it's tricky to get inside of this. Then hold it. So we're just going to bend those little tabs out of the way. There we go. We'll go to the other side here. And it takes a little bit to get the tabs bent out because they're itty bitty. But they're strong enough to hold the switch in place. Almost got them. There we go. OK, so once you get the tabs bent out of the way, you'll see that there is a board here. It looks like an epoxy board. And it's got a few pieces of aluminum sticking through. And if you look closely, you can see there's three of those. And you can see that the top, the one in the middle, the pole, it's got a bit of a bump in it. And what that does, that's important because that causes the switch to slide into position so it doesn't stick between the two positions. And let's see if we can get this to come out here. So we've got probably an ABS plastic slider. And then there's a little metal slider inside of that, a little metal piece that slides over the contacts like this. Slides over those contacts. So when it's in this position, these two-- sorry, let me see if I can get this to where you can see it. Oh, there's the contact that's popped out. Let's put that back in. There we go. So when it's in this position, these two are connected. And when it's in this position, these two are connected. So the power flows between this circuit when it's in this position and this circuit when it's in this position. Now, the way it stays in contact is it's actually kind of an ingenious little spring that's inside of here. So this is the part that actually conducts the electricity between the two connections here. And then there's a spring inside of it. And what the spring does is it pushes down on that contact. And that makes sure that it stays firmly connected to the poles and throws. So it stays firmly connected like that. And that's really important because if you don't have that spring, the contact may lift up, and then you may not have consistent power. Now, one more thing is we're actually using this switch as a single pole single throw switch. Whoa, got away from me there. We're using this as a single pole single throw switch. So we're not actually using both of the throws. So we just bent this throw out of the way, because we only needed one of the throws. And the main reason why we're using this switch for Spout is that we just got a really good deal on it. You can find it for about $0.05 online. So it's really cheap, and it happens to do the job just fine.