VHS Group project - Multiplayer Pinball

I will have some solenoid/coil/motor/whatever drivers coming. They are very general, so they can take a 5v input (low current, 4mA should be safe), and switch a high voltage on the output. Depending on how you spec the MOSFETs, you can use them to drive up to 90v/10A or so. A solid 5v input or a PWM input is fine, which could be used to drive a solenoid open, and then lower the average power delivery just enough to keep a solenoid activated but not burn out.

Unless you’re doing something special with the relays, these can replace them. They don’t sound as satisfying, though.

I have 30 coming and I need maybe 6 of those. If you need more, I can panelise them more efficiently, if you’re willing to wait a month after the first batch arrive and get tested (so, 7 weeks from now). They’re also simple enough to protoboard if you’re in a rush.

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they can take a 5v input (low current, 4mA should be safe

Great, sounds like that takes care of the concern for how much current we’re running through the microcontroller.

They don’t sound as satisfying, though.

They’ll be firing solenoids - you wouldn’t be able to hear the little click of the relay over the big thumping click of the solenoid anyways :smile:

We won’t be building out all three sides to begin with, just one side + center to test and workout kink in the design and layout - lead time on the rest of them isn’t a problem.

Current plan for power supply is 48V - and rather less than 10A per coil!

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This project looks fraking amazing! I don’t really have any time on my plate, but I’d still love to help out if there’s slack to be taken somewhere. Certainly would love to learn some electronics.

For my input on the design, It would be awesome if you had a hole right in the center, for multiple uses, could be the jackpot hole as well as a multiball dispenser, perhaps both at once? Imagine slowly stacking your balls in the center hole, every time you get one in another gets released to take it’s place, once you’ve got 10+ stacked up in the hole a piston pushes up, spitting them all out on to the field.

EDIT: If you guys want custom resin parts for decoration (a long ways away) I’d be happy to help, would be neat to have some unique bumper toppers.

Yes, you are correct. I linked to the wrong LEDs. These LEDS also use WS2812 chip in them so it will be the same principal.

I have used firmata in past projects, they use a hardware interrupt for the pins (as far as I can tell) so they announce when the change of a input happens and sends it down the serial line. You client device doesn’t need to POLL for the present value of an input, the values get PUSHED. although there is a initial POLL for the current status of all inputs on start up and “key frames” POLL periodicity to ensure that everything is how you expect it

Sweet! Thanks @Jarrett
.

@jon did a shitty photoshop edit, cause it looks so cool. I have a hard time knowing the scale of the thing so it’s tough to know what sort of room you have to put obstacles.

Those ugly blobs in the edges are meant to be those rubber band sort of bumpers, similar to : Image

@Gibbtall - sweet, great to get someone else on board, especially on the making stuff look better front!

We’ve definitely talked about putting something along the edges to throw stuff back towards the flippers - still playing around with exactly what.

It also might not be clear but the thick ovals above the flippers are going to be slingshots (what you linked) - with the playfield being triangular, they actually should be straight to kick things up and to the sides.

The general costs on active elements goes up in a hurry - active slingshot mechanisms cost around $50 a piece, as do pop bumpers. we’ve gotten some generously donated earlier from @packetbob, and I’ve got a line on a few more, but I’d really like to come up with some cheaper things to scatter around.

For my input on the design, It would be awesome if you had a hole right in the center, for multiple uses, could be the jackpot hole as well as a multiball dispenser, perhaps both at once? Imagine slowly stacking your balls in the center hole, every time you get one in another gets released to take it’s place, once you’ve got 10+ stacked up in the hole a piston pushes up, spitting them all out on to the field.

Yep, big multiball is definitely something we want to do.

Lets chat at the space some time, see if we can come up with some ideas!

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You also may want to look at what sort of cover you want for the playfield…
Normally we use tempered glass but that only works on something flat…
Keeps the noise down…
Keeps fingers out of mechanisms…
Keeps balls on the field…
Keeps junk out of the playfield…

Yep, It’s hidden in the rendering, but a covers a must have.

Probably PETG, as it’s laser cuttable and strong.

I’d love to have a look at this thing! Great work.

Been a while since I posted, an update, but progress has been happening!

  • picked up some parts
    • rubber
    • balls
    • posts
    • MOSFETs for the driver boards
    • a couple 48V 2.5A switching power supplies
      • paralleld up, these should at least give us enough juice for testing.

Got 4 of @Jarrett 's solenoid driver driver boards and test assembled one. We can fire a solenoid!

Then the laser went offline :frowning:

But now it’s back!

I Cut the first test playfield out of 1/4’ plywood - the final version will be 1/2’ (pinball standard) but 1/4 is cheaper for prototyping. Discovered that our laser cutter software will only cut up to 785mm in height, not 800 as we’d been lead to believe.

Hot glued the pieces on, and assembled!

Here’s an album with some more photos.

Some learnings:

  • cut the flipper holes too small - sized them for the flipper shaft, the bushing actually needs to protrude into the playfield.

  • Just drilled them out larger for the prototype.

  • Spacing on the slingshot is going to be tight. I assembled these with the proper rubber and posts. Will have to see if there’s enough room for the arm to actuate when I add on the solenoid.

  • Hot glue to build up the lower playfield pieces, and the walls, seems to work surprisingly well.

  • Had to build a stand to hold the playfield at the proper angle, and off the table enough for the mechanisms to have clearance. I’m terrible with traditional woodworking, and should have lent more heavily on the laser cutter and thin pieces, as I’m used to.

  • We have very few useful screw sizes around the space, I need to pick some up.

My attempts to use some 20mm plywood I found in the scrap bin for the stand didn’t go great. First, it’s the thickest stuff I’ve ever tried to laser cut ( LOTS of passes) and the layers didn’t cut evenly, and I managed to tear my thumbnail popping them out when it didn’t go cleanly through. (first blood spilled to this project…)

But in the end, it seems like it’ll work ok for the prototype.

Playing around with what I’ve got so far ( just rolling the ball, tossing it around - flippers and slings aren’t powered yet) I’m pretty happy with it. The slings are angled nicely and throw things up and over, the lane guides flow well, and the flippers seem well positioned.

It’s starting to take shape!

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Added the flipper and slingshot mechanisms, should be ready to wire it up for power this weekend. I’ve got one slingshot leaf switch mounted (very finicky) and the other side still to do.

Some more notes:

  • It was a mistake to cheap out on the prototype and use 1/4 instead of 1/2. The mechanisms all need 1/2 inch, and sandwhiching a board between is both awkward, and doesn’t let the screw (1/2) bite into the main playfield well. This’ll work, but it’s made things more difficult than it was worth
  • When I mounted the slingshot solenoids, I discovered that they sat directly on the bar of the support. This was quickly fixed, just widened up the stand.
  • I realized that the drivers @Jarrett designed for us are trigger on open, but my switches are all NO, so I’ll use a microcontroller when I wire it up.

Playing around with it manually, it appears about where I was expecting power wise - the center will be easily hittable, the sides more difficult.

Okay, Wired everything up (direct, no controller)

I couldn’t find any decent connectors at the space this weekend (have ordered some), so this involved soldering and unsoldering from the power supply to set it up.

Powered it up, and no magic smoke, or coils firing wildly! good first result!

When I triggered a slingshot, it started firing wildly. After checking, it didn’t seem that I was overdrawing my power supply, so I took the bands off the slings, and tried it - worked fine - the leaf switch was sitting too close to the band, so the bounce from the coil firing would complete the circuit again, firing the sling again and again.

This seems easiest to fix by debouncing the switch at the software level - only letting it fire after a second or so. Our leaf switches are a bit bent up, so trying to tweak them for exactly the right amount of sensitivity would be a long and painful process. Proved the concept, I’ll leave it at that :smile:

One of the flippers fires and works correctly - even properly opens the flipper hold switch to reduce the current through the coil.
The other flipper has a sneaky short that I’m trying to figure out.

As it’s generally been successful, I’m going to move to using the driver boards and a controller. Also try and figure out my one shorting flipper.

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So, looks like the coil itself on one of the flippers is shorted, and compounding the bad news, when checking the resistance on the other coil, I discovered that it’s also shorted out some of the windings, and will likely burn itself out in short order.

I guess time to buy some new coils…

do the coils have the # on them?
i may have some spares…

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SFL-23-600/30-2600
I believe this is the part. (it matches what was originally in Comet, too).

Thanks!

IT LIVES! or at least flips.

John’s Jukes turns out to have relatively reasonable pricing on coils, so I picked up a replacement coil locally.

Installed the replacement for the shorted one, tested the resistences, and it appears equivalent to the one in the existing flipper, so that’s good news.

With that installed, flipped it over, connected the power, and started testing: (apologies for the vertical videos)

testing the flippers:

testing the slingshots:

So far so good! Both flippers and the slings are able to throw the ball to the top of the table, but not too much.

I built a bit of a temporary “rear wall” out of some scrap acrylic and wood that was lying around - lets me test the single side.

then started gluing some additional parts on, and testing how it shot:

One of the flippers ( the one with the new coil…) is weaker than the other. As both appeared to have similar resistances, I suspect this is due to the end of stroke switch being finicky.

I’m also looking forward to some high amperage connectors I ordered showing up - currently setting up the table to test requires soldering some wires together!

Next step is more layout tweaking, and once I get positions I’m happy with, putting them into the CAD model.

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Could also be due to the plunger or its sleeve in the coil…
The plungers tend to get mushroomed a bit on the bottom from hitting the stop and the sleeves wear out…
Can’t remember if those were all new parts or not…

Looking awesome @jon. I like that the balls go down all three of the lanes next to the flippers. I was worries that the gutter would never get used with the bumpers on the wall.

So this is what I was thinking for the center “wormhole” trap/multiball hole

Here’s the onshape file for those who want to give it a twirl:

Essentially it consists of an acrylic tube, with an elevator that rides along a slot in the side of it. The elevator would be attached to a belt driven by a stepper motor, much like the Tinkerine belts in my mind. The elevator would start near the top, there would be a microswitch at the top that would read when a new ball has entered the tube, and would tell the motor to drop down 1 unit (the standard ball height). That way you reduce the amount of impact from incoming balls, and once the tube is filled (this mockup is 20 balls high for a height around 50cm, so could be bigger depending on the space we’ve got available) it’ll reverse the elevator all the way up and spit all the balls back onto the field.

The elevator design can be optimized to make sure that at it’s peak it’s flush with the table surface, in order to close off the wormhole when not in use, maybe while the multiball mode is running. Also it would need some fiddling to make sure it doesn’t hit the upper belt wheel once we know what to use.

I’m still a bit worried about the strength of the stepper motor, 20 pinballs is 1.6 kg, so I’m not sure whether it will have the torque to move that much?

Fibertek has Acrylic rods, so we can even see the pinballs in the tube, I’m not sure where to get the motor, switch, drive belt or wheels, buuut you guys do, so direct me!

Yeah, it would be better to have the tube closer to horizontal, with a curve to push only the balls at the top vertically. Neat idea though!