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GemHunt / CoinSorter

Sorts coins by solenoid on a conveyor by classifying images with Caffe & DIGETS
MIT License
46 stars 2 forks source link

Come up with a better coin switching mechanism #17

Closed pkrush closed 8 years ago

pkrush commented 9 years ago

A solenoid certainly seems the most logical.

Such as low cost push solenoids to knock/hammer coins off the belt: Maybe some type of foot it's more then just the rod end, but try without a foot first.

Rotary solenoids seem like a good idea, but I have not seen many.

If you position you could sort to more than one bin: RC servos since they are so common and easy to control. Cheap stepper motors might not be a bad idea. A step past a rotary solenoid.

pkrush commented 9 years ago

Solenoids have a short travel so it might be better to switch on the thickness of the coin. Also they pull in. So a solenoid closer to the hinge with 2.5mm travel can drop a slide say 6 mm down on the end. I have to post a drawing.

pkrush commented 9 years ago

Lets change this to: Come up with a new coin switching mechanism, and do it in less then an hour, and don't care if it works...

pkrush commented 9 years ago

A friend mentioned air which would go great with all sorts of other small parts as well. I tried it, it does work with little air, but it does require a compressor.

pkrush commented 9 years ago

I tried just a push pull solenoid. One that has the plunger coming out of the back so it can push when powered. It's pretty cool. You can shoot the penny like a billiard ball and cause it to fly off in different directions. This is cool! If I have good timing I can use one solenoid to fill 3 different buckets.

image

pkrush commented 9 years ago

This is fun. So the next task is to make an pinball game with pennies.

pkrush commented 9 years ago

If you used PWM you could also vary the power to hit different buckets. But not if your using a relay. I need to test with a relay. Also a looping test track would be nice to try to wear such a system out. I worry the plunger will mushroom over.

pkrush commented 9 years ago

Applying billiard ball English with the solenoid end just works to hit 3 bins with one solenoid. I tested this with three push solenoid settings: -50ms Zero (coin center) +50ms The belt is running at 72mm per sec. So this works out to hitting the 19mm penny 3.6mm off center. It’s pretty consistent and there is room for the timing to be a little off. The end of the solenoid is a flat rod. (It’s threaded M3-0.5) I am thinking you can hit the coins into PVC pipes built into the frame and put bags under the pipes. Also at least for test I would like IR sensors in the pipes to prove the system is working correctly.

Also the solenoid is strong enough to so this with half dollar coins (11.3g 30.5mm). This is largest common US coin.

pkrush commented 8 years ago

So design and make it: 3 way solenoid sorter: Uses cue ball English and a push solenoid to pop coins into one of three PVC pipes. Sequentially sorts all the pennies so none should fall off the end of the belt. Put in IR sensors to test if the system is sorting correctly.

pkrush commented 8 years ago

Some bins will be smaller some bigger. Try using 1 liter pop or water bottles as they are cheaper and more common then PVC Pipes! You can slide coins to bags, boxes, whatever.

pkrush commented 8 years ago

I build one test conveyer with a solenoid...

Test the English on this one: Make and install the new top plate. Mount the IR sensor and LED, solder and heat shrink. Solder 2 motors with flexible wires. Test the English Can I detect stacked coins?

Revisions needed: Make the conveyor longer to have the 3 buckets Redesign the top plate Move the solenoid away from the motor. Solenoid plate should have locator tabs I wonder if the nuts should be different heights so all the screw lengths are the same? Use all 3mm screws? Somehow I cut 3mm end plates mirrored, be careful next time. Clearance holes in the side rail to tighten the solenoid plate? The motor axis can be moved 1mm down in Y. Clearance for a light strip Bigger holes for bushings. Lift side rails above the ir sensor 0.5mm Can the end plate be any wider to square the side rails more? Keep the old conveyor together. Build a new conveyor and start building the assembly instructions at the same time.

Start of assembly tips & instructions: Cut coupling tubing 17mm Cut 30mm wide belt 7 ½ inches long, bond smooth side in. Tape before heat sealing. Mirror the side rail when cutting. Don’t tighten top plate super tight as it will crown. Cut 2mm shaft 41mm long Cut 2mm shaft 57mm long Drill out bushing holes with a #13 drill Squeeze the side rails when screwing on the end plates.

pkrush commented 8 years ago

I call this done with the solenoid pictured above knocking coins into 2 different boxes. It will incorporated into the scanning conveyor.

pkrush commented 8 years ago

I used an IR sensor and one solenoid to push the coin into 3 different bins. This is useful, but complex. If I use one bin per solenoid and have a wide foot the tolerance will go up 10x. I can add a wide foot to the solenoid since it’s pushing into a 4” wide box. Instead of needing to get into a 3mm window it can be a 30mm window! I don’t need that many bins at first, so using one solenoid per bin will be much easier to start out with.

Why are IR sensors bad? Both the LED and sensor have a resistor, this is a lot of wiring. They could get dirty. There is code and tuning involved.