Coins-Worth Update 7/18

Coins-Worth prototype Version 2 is coming along nicely.

“What’s the hold-up?”, you might ask. Since I’m new to manufacturing and 3D printing, I’m having to do a lot of trial-and-error in creating the parts design. This isn’t a bad thing, since it drives me down a number of learning curves that are fun and, well, educational too. For example, I’ve been assuming that the device parts will simply “fit together”, but the last few days I’ve been thinking about how to actually fasten them – possibly with screws at the corners, for example.

Anyway, here is the current state, along with a picture of a partially-assembled Coins-Worth with servos. You can click on the picture to get a larger view, and come back to this description for the details.  The whole unit is laying on its side while I test placement and fit for servos and various parts, so some of the parts aren’t exactly in their proper position.  I hope to have it all assembled mid-week, with servos ejecting coins from the stacker station, landing on the scanner station, getting flipped, and then falling through to a bin below.  My goal is to send 2 coins a second through it — sorting out collectible and silver at 120 coins a minute!

Coins-Worth as of 7/18/2014.

Coins-Worth as of 7/18/2014.

  • The big white part farthest away is the “back panel”.  It has slots for things to fit into, and there is also a “front panel” (not shown, because it would obscure your view of everything!) that will hold up the near-side of everything.
  • Just outside the back panel to the upper right is a small 9 volt battery holder, and a Pololu Maestro servo controller.  The battery supplies power to the servos, and the Maestro is connected to Pololu’s Maestro Control Center application via the mini-USB plug attached.  (I can control the servos manually from the Maestro Control Center for testing purposes.)
  • The two blue boxes are Osepp LS-0003 micro servos, each connected to a specific port of the Maestro controller.
  • Just above the right-most servo is the “stacker section”.  You’ll see two plates there, one to hold the stack of coins and an “ejector plate” that is actuate by the servo to send one coin at a time off to the left.  There is a tube holder not shown, which sits just above the two plates.
  • Just above the left-most servo, all sitting at a 25 degree angle, is the scanning station.  Coins rest on the one larger plate, and there is a smaller V-shaped catcher which stops the coin from falling through.  near the left-most edge of the scanner plate (and half way, front to back as shown) is a small hole.  The servo will elevate a small pin through that hole at the leading edge of the coin, to flip the coin.  (Heads and tails, but you don’t know which way it will land initially.)  The servo is placed so that it can lift the coin catcher enough so that the coin will slide down and to the left.
  • Not visible here is a small ramp which will direct the scanned coin to a chute, which will send the coin into the appropriate sorting bin.
  • In the upper left you see the Logitech web cam (very dark, barely visible) sitting in the camera holder (light white box with camera peep-hole in it, suspended 2 inches above the scanner plate).  I’m hoping to include an on-board USB hub, and connecting the servo controller and web cam to it.  Note: I’m currently designing with a Logitech C615 web cam, but hopefully can find a usable camera that is less expensive.
  • There’s a bottom piece which the back panel and right panel (a simple, plain white rectangle) are slid into, and a partial top piece which holds the back and right panels together.

All white parts were designed in FreeCAD and 3D printed on my Lulzbot TAZ 4, using Pronterface/Printrun and Slic3r.

Coins-Worth, with all currently-designed parts assembled and upright.  7/20/2014

Coins-Worth, with all currently-designed parts assembled and upright. 7/20/2014

Here’s another view, with all of the parts I’ve designed so far – though many of them are hard to see, because they’re behind something else.  This is taken from just above Coins-Worth, looking down through the top.

The camera is more visible here, sitting inside the camera bracket.  Just barely at the lower right corner of the camera’s base is a nickel, sitting in the scanner station.  Also visible is the coin-stacker tube, with a penny sitting at the bottom, ready to be ejected down to the scanner station.

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