Videos - The Coin Bot

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00:00:00	hello everyone and welcome back to the channel uh in the last video we were talking about this little device here uh it is the coin sorter and that allows you to drop a penny anywhere on this and it will
00:00:15	always end up in that little hole over there so that is pretty handy when you're trying to sort out coins and that was the next layer in our coin sorting robot design but when you first turn a machine on
00:00:31	there's no way of knowing what position this Servo motor is in unless you have some way to account for that so in order to do that I thought I would introduce some limit switches and I looked on Amazon and
00:00:45	there was a couple of different designs but as it turns out this actually seems a little bit large for what I'm trying to do here but you can see how this works that something would run past here or bump into this and it would act at
00:01:00	this switch these are marked in three different positions for uh n o NC and C this means that this is nor the normally open position the normally closed position and this is the common position so this would be shared between each of
00:01:18	these two positions but you really only need two wires to connect to any limit switch depending on whether you want it to be normally open or normally closed the only other limit switch that I found on Amazon that would fit the bill was
00:01:32	this one right here again it has three pins for normally open normally closed and the common pin so I thought that what I would do is try to build a mount now because I'm absolutely perfect and I do everything right the fifth time you
00:01:50	can see how many times it took me to print these particular Parts in order to get it right but what I did was basically I took this smaller limit switch and I designed and I broke the design into smaller pieces you can see
00:02:03	that this little rectangle here is actually just a smaller portion of this coin shelf that I have so I didn't have to waste so much plastic when I was printing this out but uh the basic gist behind that
00:02:17	was to make sure that I could still get the alignment of this so I get the center hole and then I could adjust where the limit switch holder was over here so that it was actually activated by these cogs as they're going
00:02:32	around so uh this was my first attempt and you can see that the limit switch it fits in there but it didn't quite leave enough room for the switch to activate in there it doesn't actually set down in there all the way and you can see that
00:02:47	there's interference there uh one of the things that I did do was I cut that lever off just a little bit on one of these just so that I could fit that down inside there a little bit better and see if it would actually work
00:03:00	um if I had a better design so uh you can see that this actually works in that position but I really needed to adjust the the size of this holder so that it was a a better fit and then then this version I I left room for the the wires
00:03:18	to come up through the bottom of this so we're making some revisions and I also put Notches at the top and bottom of this so that we can't slide this forward or back we wanted to control very precisely where this limit switch is
00:03:33	located so that we know that this switch will only be activated one time and the uh final version that I ended up with or close to the final version was uh much bigger I had a lot more room for this lever up here you can see now that we
00:03:51	can actually activate that switch and it will move appropriately so that's great now the final version of that in the finished coin Grabber design looks something like this we have the limit switch in here
00:04:10	that's activated by those cogs as the coin Grabber spins around and we also have a hole here for the wires to pass down through the machine and we can connect that to the other electronics that are eventually going to go in here
00:04:23	now if you listen to this you can see that as these uh compliant mechanisms move past the limit switch it sounds like the limit switch is actually activated two or three times
00:04:38	and that kind of scared me if you listen closely you can hear three clicks every time one of those compliant mechanisms go by but I did some testing with a continuity tester and it turns out that
00:04:55	this little lever here isn't actually being activated three times it was just actually clicking on some of these catches as it as it came around but it all seems to be working and it's really only activating the switch once when
00:05:10	this compliant mechanism Cog is actually at its highest point so that's the only time that the the limit switch is actually being activated that should give us the position of the servo motor when those are at Peak and that will
00:05:25	allow me to adjust so that this is in turn right directly over the camera when it's rotating through the positions so that's kind of nice if we put that back on here you can see that the limits which is in there it's not uh
00:05:39	you know it's not interfering with anything and you can hear it actually being activated but for now I think that's my two cents thanks for watching everybody stay awesome