Videos - The Coin Bot

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00:00:09	Nice. Hey, what's up, everyone? Welcome to the channel. If you're new here, this channel is about me trying to build a robot that's capable of finding coins for me to add to my own coin collection.
00:00:26	In the last video, we discussed some engineering design principles and how mine have changed. But I promised to share with you some of the initial ideas I had in my head about my own coin roll hunting machine. So in this video, I'd like to take you on a little tour
00:00:44	of how my mind works and show you a little bit of my process for thinking through a design, and I'll catch you up to where I am currently in my design efforts, so far. My first idea was to place the coins on some sort of conveyor belt that would pass the coins by a single camera, flip the coin over, reverse the conveyor belt, and allow
00:01:03	the camera to take an image of the other side of the coin. That way, both sides of the coin can be photographed and identified. Initially there's no way to consistently know which side of the coin will be up on its first pass. And we need to take a picture of both sides of the coin in order to positively ID the coin.
00:01:24	However, I couldn't think of an efficient way to flip the coin over before reversing the conveyor belt. My new design involves something that I like to call the slider. It's a thin strip set in motion by a stepper motor that has a coin shaped indentation in it, perfectly sized to hold a particular denomination of coin.
00:01:44	The outer diameter is perfectly sized to hold the coin in question, and there is a smaller ring on the bottom that keeps the coin from falling through but doesn't obscure the coin design. That way, both sides of the coin can be photographed at once and positively identified. The idea is to have the coin pushed into position between two cameras,
00:02:04	and each of those cameras will take pictures of their respective sides. The AI will then identify the coin and drop it into a sorter. I thought one of the major advantages to this is that there would be a correlation between the two images, and if I could get the AI to orient one side properly, I could use that information to orient the other side when it was presented to the user.
00:02:27	Theoretically, I could also catch coins that contain a rotated die error using that method. As you can see, there's a coin chute that drops the coin onto the slider. And the slider moves the coin into position between the two cameras. But as you can see,
00:02:42	there's no real efficient way to drop the coin after it's in this position. So that made me think of another idea that involved grasping the coin in some sort of grabber. My concept for the coin grabber was based on a PCGS coin holder inner core. On a side note, I don't like PCGS holders.
00:03:00	So I tend to crack them open and keep the rubber core. I imagine the coin being picked up when the slider was moving in one direction and being released when the slider was moved in the opposite direction. That being said, I hadn't really worked out the mechanics of that.
00:03:15	But I pictured a rubber band holding the clamp shut in the forward direction and then it releasing in the reverse direction with a temporary catch. I also want to show you what I have in mind for the other components, but I want you to keep in mind that I want to have a form factor that's capable of sitting
00:03:31	on my desktop. So it needs to be pretty small. So that required a little bit more thinking. And as I got thinking about it a little bit more, I think I can actually reduce the part count from that rubber band grabbing mechanism that I had in mind and just change the configuration of the slider so that the coin
00:03:50	actually just slides off the back. As you can see here in the new design, as the slider is retracted, the coin that was in position collides with the next coin in the queue and it is pushed off the front of the slider into the coin sorter. The coin sorter is just a large cylinder with a hole drilled through the
00:04:10	center of it and a camera below it. The downspout of that coin sorter is actually directed to the outer edge of the larger cylinder. That way you can direct where the coin ends up by spinning the outer cylinder with another stepper motor.
00:04:24	The larger the cylinder, the greater number of sorts you can perform, but the smaller the diameter, the faster the cycle time. So there is some compromise here. So that's really what I had in my head Regarding the initial design of the coin bot. But then I started putting out YouTube
00:04:40	videos and someone introduced me to Numan. No, not that Newman. Numan is a machine that was designed by a coin dealer named Tim Rothjen that sorts coins by date. And it really changed the design requirements of my own machine. But we'll save that discussion for the next video.
00:04:59	If you like this type of content I hope you'll smash the like button, that you'll subscribe to the channel, and that you'll hit the notification bell, so that you don't miss out on any future videos. I also hope, as we discussed in the last video, that you leave a comment down below if you have any
00:05:11	feedback for me or if you think I'm barking up the wrong tree. Until next time, I hope you have a great day, and I look forward to seeing you in the next video. Thanks, everyone. Take care.