Homebrew Pinball #3, Part 90: Pintastic Post-Mortem

Cross posted from the original Pinside thread, this is one of many posts regarding my third homebrew pinball machine, creatively nicknamed 'P3'

Overall, the game got approximately 400 plays at the show.... I think. Before folding it up for transport, I also coded in a bunch of audits and stuff so that, for every game played, it'd store a big data file full of stats, timestamped, for me to dig through later. By counting those files, I reasoned, I could get the play count easily. There's just one problem: it turns out the RPi doesn't have an internal clock. Whenever it boots, it gets the current time from the internet. And there was no internet at pintastic. So when that happens it just picks up where it left off, meaning that the first games played on Friday were timestamped at some time Wednesday when it was last connected to the internet, and the games on Saturday look like they came right after the ones on Friday, so I have no way of actually knowing exactly which games were played which days. I tried to reconstruct everything as best I could, so I think my numbers are pretty accurate, but it's annoying that I don't have perfect results...

Anyway, some fun stats:
- Total Games: 382. Of those, 345 were single player. 28 were two player, and a few three and four player. No one did a five player game
- Top score: 2,297,380, by 'OLP'. Congrats, whoever you are!
- Lowest score: -584,410. Even more impressive. I've never seen someone get half that low of a score. Sadly no initials were given for that game
- Average score: 400k. Pretty good. When I started writing the rules for the game I wanted 1 million to be obtainable, but not a 'gimme'. You should be excited when you get a million points! I think my balancing has done pretty well on that front.
- Scores over 1 million: 32. That's about 8%, which would also put the 'replay' score right around there too, nice
- Most money lost: $4810
- Most money won: $5880, again by OLP. They must have been good at poker... This cash in also got them the 'Top Cashout' high score at 1,542,850. More than half their score from poker!
- Most hands won: 4. 4 is a pretty good game... I think the max I ever saw someone get during testing was only like 9, and they were familiar with the game and concentrating on just winning hands.
- Most hands played: also 4. So whoever played that 4 hand game had a 100% win rate, wow!
- Average cashout: 140k. This is slightly off since I realized that I had a minimum cashout of zero, meaning that anyone who lost points is going to be counted as just a zero, bringing the average up, but I don't think it'd affect it that much. Considering that the average score was 400k, I think this number is pretty well balanced. Maybe it should be a tad higher? I don't want the game's scoring to all come down to the end of game cashout, but also, it's Poker, you know?
- Average bonus: 50,000. This feels a bit too high to me, considering an average game is 400k. Almost half people's scores is coming from bonus? I'll probably have to tweak this a bit lower.
- Multiballs played: Hand: 84, Straight: 13, Flush: 10, Full House: 12. Nice to see that the three main multiballs all had similar play counts, but the discrepancy between 'Hand' multiball (the 'gimme' multiball for completing your first hand) and the rest is a bit higher than I'd like. When watching people playing, I noted a ton of people were lighting multiball but then not starting it. At first I worried they didn't know how to start it, but even when pointing it out, they still couldn't do it, so I think really the ramp shot is just way harder than I thought it was. I wish I'd made an audit for 'multiballs qualified' vs 'multiballs played', I'm sure it would be quite depressing
- Flubbed multiballs: 68. Also depressing... 68 of the 119 multiballs played scored zero points! I guess people just forgot to flip or something? There's no ball save so I know the multiballs can be short, but I'd expect most people to at least get to bat the ball around a bit. Similarly, not a single person got a jackpot in Straight multiball. I'd thought that one was easier than the jackpot for full house, but one person did get a nice 700,000 point jackpot from full house
- Most skillshots made: 7. That's a pretty good number. Again, I think the high ever was only around 9. Sadly this is counteracted by...
- Zero skillshots made: 232. That's not single skillshots either, that's entire games played where the player didn't make one skillshot. More than 50%.
- Biggest spinner rip: 58 spins. The average spinner rip is only around 20, so that's really amazing. Maybe they managed to combo it and get two hits in?
- Ball Times:
- Game Times: these were a bit lower than I'd hoped. I think optimally a game should last around 3-4 minutes, but the majority were shorter than 3 minutes. I'd put a lot of thought into trying to make the game easier for less skilled players, but couldn't come up with that many ways to do it without making it easier for more skilled players. A timed ball save would probably help here by just inflating the minimum possible ball time, but I'm not a big fan of them in games where you can plunge directly to a flipper, AND have savers on both outlanes to help you...
- Average poker hand win/loss: 1.47/1.05. Not bad. I guess at least some players are trying to play the poker a bit, otherwise I'd expect an even distribution
- Right outlane ball save used successfully: 68 times. Sadly this number isn't that useful without a 'number of right outlanes' audit, but it's nice to know that 68 people got to have the 'saved the ball using the popper' moment. When watching people play, this is probably the most exciting, successful moment that I saw
- Ramps shot: 99. Surprisingly low across 400 games, but people just seemed to have a ton of trouble lining up this shot for some reason.

And finally, all my audit data, zoomed out to fit on screen

Posted Tuesday, December 07, 2021
at 09:23 PM

Tags: Blog Post, Pinball, Project, P3,

Homebrew Pinball #3, Part 89

Cross posted from the original Pinside thread, this is one of many posts regarding my third homebrew pinball machine, creatively nicknamed 'P3'

Heading to pintastic, I was mainly worried about three things: broken 3d printed parts, ball sticks, and something going up in smoke. I arrived early Friday morning and set the game up in the free play area:
A quick inspection showed that everything had survived the journey intact, except that the upper 3 bank of drop targets had nearly worked its way lose from the playfield somehow. I'd never seen it come loose at all before, so this was a bit of a surprise, although considering that, for various reasons, it's only held in by two screws, I probably shouldn't have been so surprised. If any bank was going to do it, it'd be this one. It was at this point that I also discovered I didn't have any half inch, #8 wood screws, which I'd bought specifically to replace loose #6 wood screws (which is what I used for everything on this game) with in exactly this sort of situation. But I did have 3/8", and I reasoned that the thickness was probably more important than the length here, so I installed those. A few test games, and a quick chat with the creator of the Pincraft homebrew who walked by, and then I reset all the high scores and pronounced it "good to go" and left to check out the seminars.

I came back a half hour later to check, and the game was... still working! Had a few nice chats with players, and got a quick interview done by a youtuber, and then I left again. I tried to check on it every half hour or hour or so throughout the days, but I wasn't planning on really being there the whole time and sometimes I didn't get back for 4 hours at a time.

Issues encountered, day 1:
- about an hour in, I came back to check on it, and it was turned off! Uh oh, what could have happened? So I turned it back on and it all worked fine. No idea why someone turned it off, and didn't try to contact me
- soon after, I got a text that there was a part loose on the playfield. Turned out to be a random 1/2" wood screw. I searched all over the game but couldn't locate anywhere missing the screw, so I just tossed it in my spare parts and closed the game up again
- another text, another part loose on the playfield. This time it was the spring off my left inlane gate. There's nothing holding this on besides gravity and friction, so I'm honestly surprised this had never happened before but, more than a year of testing and it didn't, so I never worried myself about improving it.
Oh well. I put the spring back on and we're good to go
- came by, a player was trying unsuccessfully to start a game. "Ball Missing". Oh boy, we finally have a ball stuck! I confirm there's only 2 balls in the trough. Search high and low all around the playfield... no ball. I finally find it in the coin box area, sitting right on top of one of my boards, but no damage luckily. No clue how it possibly could have gotten down there.
- another part on the playfield. it's the spring again. I reinstall it.
- game has crashed. The cause? No space left on the SD card; my debug logs have filled up the entire 32GB. I sorta knew this was a possibility, but besides from turning off the logs I hadn't found any good solution since I can't delete the old logs while the game is running easily. I delete the logs and restart the game, problem solved.
- another part on the playfield. it's the spring again. Grr. I wonder if maybe the spring has gotten stretched out over time, and replace it with a new one. Maybe the extra tension will hold it on well enough?
- while showing the game to someone, I notice that the left outlane diverter gate is stuck down. Did the mosfet blow? Nope, it's being PWMed properly to stay down, so the driver board software is working properly. The game software thinks it shouldn't be engaged though. Something must have gotten out of sync between them, so I restart the software and it resolves the issue. No idea how long it was like that, but the coil still hadn't gotten hot, so I guess my PWM settings must be pretty good. I'd considered just having the gate stay down during play (vs turning when the outlane switch is hit) but had been worried the coil would eventually cook, so I'd avoided it. Might be worth another look since I've been having issues where the gate doesn't turn fast enough to divert balls
- someone reports a stuck ball. hopefully it's not in the cash box again. nope! It's... stuck on the left inlane gate. the new spring is just strong enough that a very slow ball isn't heavy enough to push the gate open. I try to stretch the spring a bit and find a happy medium between the two and cross my fingers
- finally, near the end of the day, I again get a stuck ball reported. This time it's sitting in the outhole, and not getting kicked over. I worry there's a switch issue, but it turns out the coil fuse for that bank has blown. I replace it and get ready to turn the power off quick once I see what's locked on but the game works fine. Not sure what blew the fuse. Looking at it, it's a fast blow, 4A. In retrospect that probably should be a slow blow to account for random situations where too many coils just happen to fire at once, but it's never been a problem before, and I'm wary of swapping fuses at the event, so I put another 4A in.

Day 2:
- while showing the game to @McSquid, the left drop target bank starts having trouble resetting. Luckily, my code will retry a few times and then give up, so it's not a huge deal, but after the game I check it out and see that it's starting to come loose like the 3 bank did the previous morning. Again, this is a bank where I had to remove one of the 4 mounting brackets to make it fit, so maybe that's a problem, but there's not much I can do about it. I swap in some #8 screws just in case
- a few hours later I get a report that the game is 'stuck'. When I get there it's sitting on the bonus collect screen, but not counting down. Somehow, the bonus 'total' that's supposed to be awarded has become NaN, which basically means a divide by zero or something happened somewhere. The game keeps trying to subtract 1,000 from the total and give it to the player, but when you subtract something from NaN you get... NaN. Not sure what caused it, but a reboot fixes it.
- a couple more uneventful hours pass, and the NaN bug strikes it's head again. Weird that this didn't happen on day one, but twice on day two, but nothing I can do about it right now
- another part on the playfield. it's the spring again. I reinstall it. Looks like this will just be a thing for now. I'll try to make a new version of the gate with some little overhang to hold it on in the future
- around 8pm, the fuse blows on the outhole again. Still no idea what's causing it, but again just replacing the fuse fixes it. I suspect that maybe the left outlane gate (which is on the same solenoid bank) might be stressing out the fuse when it gets stuck on, and that combined with some other coils may be blowing it?

And that's it! Not a single broken 3d printed part. No smoke. Not even any real ball stick areas for me to address. The game was received pretty well; a lot of praise for the lower flipper and the right outlane VUK/popper once I explained it.

That's probably my biggest 'failure'/takeaway from the weekend though... Most people didn't pick up on any of the more advanced features/rules I'd worked in while playing. A lot of people got confused by the secondary flipper buttons for the magna save and popper, and I'm reminded sadly of the new Black Knight's action button magna save. Not many people actually picked up on how the poker hands worked, or at least, they didn't have the flipper skills needed to actually aim at good cards. Most people just flailed around at the targets and got random hands, then double flipped through the 'end of hand' animation without even noticing if they'd won or lost. Also, very few people figured out the skillshot. Most just full plunged, which tended to send the ball flying all the way around to the left inlane to their surprise. I thought I'd done a pretty good job of making the skillshot obvious, flashing the lights brightly, etc, but apparently that wasn't enough. It's a bit saddening to see, but I guess that's just how a lot of players are. I don't really plan on changing anything on that front though; I didn't design this game with the 'mass market' as my goal. When possible I've tried to make it so the layman player can also enjoy the game as much as possible, but I'm not going to remove features that expert players can enjoy just because they may slightly confuse other players.

Posted Tuesday, December 07, 2021
at 07:56 PM

Tags: Blog Post, Pinball, Project, P3,

Homebrew Pinball #3, Part 88

Cross posted from the original Pinside thread, this is one of many posts regarding my third homebrew pinball machine, creatively nicknamed 'P3'

Finally got the game set back up again after its trip to Pintastic, so an overview of the past few weeks...

I didn't want to mess with the functionality too much since things had seemed mostly solid, so once all the art was done, I tried to focus on finishing touches.

I wanted to cover up the apron since it was just a clear piece of plastic and a bit ugly, so I had the random idea to just use green felt like on a poker table. And what goes on a poker table? Chips! These are just super-glued together, but they're holding up alright. With the lockdown bar and instruction card on, it doesn't stand out too much

At the request of a tester, I added a quick shooter gauge. I would have liked to use an existing one from a game with some nice art, but none fit the weirdly shaped bottom corner I ended up with...

And, as a last finishing touch:

Leading up to the event, I had a few people by for last minute testing. This mostly went well, just a few bug reports, and mostly not game breaking, so I was able to resolve the important ones in time. With just 2 days to go however, suddenly the game completely died. No lights, no displays, and half the coils wouldn't fire. Eventually I found that the 5V fuse had blown, which would explain why the displays and lights died. I'm not sure what caused the fuse to blow, other than that I found one of the power connectors the for the displays had come off the board, so maybe it somehow brushed something? But it's not really a connector with exposed metal or anything. Anyway, the 5V also powers the mosfets for the solenoid drivers, so without that, some coils weren't getting enough power to fire. Sadly the way that they were getting power was that they were somehow powering themselves off the 3V from the CPU chip through their inputs, which managed to also smoke the CPU from the stress, so I basically had to rebuild both driver boards. Wish I'd noticed that I'd blown a fuse quicker, but not really sure what to do about that problem overall, so instead I just packed 2 spares of every chip used on the boards, in addition to a whole spare driver board, and crossed my fingers that'd be enough. Next game I'm going to try to move to a completely different architecture for driving my mosfets so hopefully this won't be an issue anyway.

Besides from spare chips and driver boards, I also prepped 2 spare Raspberry Pis (although I've never had one of those fail) and 3D printed spares of every single part in the game, since I wasn't sure how the 3D parts would hold up. I've had some games at shows get 200+ plays in one day, and looking at my audits, I've played less than that many test games during the entire development cycle, so despite the game being mostly solid for the past few months I really was moving into new territory.

Posted Tuesday, December 07, 2021
at 06:27 PM

Tags: Blog Post, Pinball, Project, P3,

Homebrew Pinball #3, Part 87

Cross posted from the original Pinside thread, this is one of many posts regarding my third homebrew pinball machine, creatively nicknamed 'P3'

With a month and a half to go until pintastic, I was in a pretty good spot. The game was working fairly well, I had most of the features done and lots of issues worked out. I figured it'd just be finishing touches and bug fixes, and I was actually ahead of schedule! So then I got to thinking if there was anything else I could do in the leftover time. One thing that'd stood out from testing is that my pencil-drawn instructions and labels on the playfield weren't readable enough for people to notice. So I figured maybe I could draw up some simple text boxes on the computer for those. Using some gottlieb EMs as reference, I found out what font was usually used, and tried to copy some of their basic styling, and I drew some stuff up in inkscape
Those didn't look too bad! So I got a bit more adventurous with some of the other instructions I had.

But I needed to figure out how to get those onto my playfield... When I first started drawing these I'd figured I'd just get some "clear sticker paper" from Staples, but it turns out that... doesn't really exist. I ordered a few things like projector transparencies and decal paper, but those also didn't work out. Everything ended up transparent still, not opaque ink on a clear background, so they didn't look too good
After a bunch of searching, I figured that what I really wanted might be "window decals" which... aren't decals. They're just vinyl stickers. I ended up ordering some from signs.com since they were the only site I could find that had an exact scale option. I got both decals and window cling, thinking that the decals might rip up the wood but the cling would have a weaker adhesion, but it turned out the cling couldn't stick to the wood at all, and the decal's stickiness wasn't too bad

The decals went on fine though, and had pretty good 'blocking' so the woodgrain didn't show through, although some of the pencil was barely visible in some of the lighter colors so I had to go back and erase all that.

With that looking pretty good, I went ahead and spent a few evenings drawing even more instruction blurbs. And then got on a bit of a roll I did a few smaller things like keylines for all the inserts. And some graphics for the magna save, and around all the displays. And then I did all the major shots and lanes too because why not? Now I had to tear down the whole playfield to install all these.... Most of the small ones weren't too bad. The larger ones (some are up to 20 inches long) got a bit more complicated though, especially the ones that needed to line up with lots of different playfield features. I'd never really done decal work before so I had to figure it out a lot as I went, but luckily they were forgiving enough that I could peel them off a few times to get them right before they started to loose their strength, and were slightly stretchy too so I could bend them a bit to line things up. That stickiness also became an issue though when I tried to put some over the displays, and the stickers started to sag down over the hole.
I ended up having to cut out some spare plastic sheets to cover the displays with in order to support the stickers. Then a new problem was revealed, as the backlights of all the displays had some light bleed that was showing through the stickers and didn't look too good, so I had to mask off portions of the plastic with electrical tape

There was also a few issues with the center, clear portions of the stickers not adhering to the plastic perfectly, creating bubbles or trapping little bits of dust, so I also had to manually trim out the center portions with an exacto knife in some cases

The biggest challenge, however, was also the biggest sticker. Somehow this massive part, which I couldn't find some way to split up, didn't come out one-to-one scale, despite being in the same file as everything else
The piece should be 23x8", but instead it was 24x8.5". A small enough different that I didn't notice it during proofing, or when I got the sheet, until I cut it out and actually put it on the playfield. And since it was the biggest, most complicated piece, I saved it for last too At this point, there was under two weeks until pintastic. It'd take at least 2-4 days for another decal to be made, plus 3-5 days to ship, and I still needed to reassemble everything and do a bunch of final testing, so I didn't have time to wait for a replacement. At first I figured I'd just leave it off, but that one decal was basically a whole quarter of the playfield, so it was really obvious. In a flash of 1am, "nothing left to lose" decision making, I decided to just cut the whole decal up by hand and rearrange it to fit.
This went... much better than expected. In the end the one decal became 16 separate pieces, which I then cut apart, layered, and stuck back together so that all the keylines still matched up. Close enough! With the plastic protector over it you barely even notice. It'll be fun showing it to people and seeing if anyone asks about it. I've ordered the correct decal, along with a few other corrections too, so the next time I do need to tear the playfield down and get the protector off, I can replace it.

Since I was already ordering from a printing place, I also got some reverse-printed decals for my plastics
They weren't quite as vibrant as I'd hoped, but still much better than my inkjet-printed ones are. Plus they're adhesive, so the paper doesn't sag under the plastic. Before:
Aaaand... done! I wish I'd been able to come up with a few more bits of actual art besides the one hand of cards between the flippers, but I wasn't able to really find anything else that fit with the theme and art style so far.

Posted Tuesday, November 16, 2021
at 11:49 AM

Tags: Blog Post, Pinball, Project, P3,

Homebrew Pinball #3, Part 86

Cross posted from the original Pinside thread, this is one of many posts regarding my third homebrew pinball machine, creatively nicknamed 'P3'

Falling behind on updating this thread as the final crunch intensifies

Lots of little things going on...

I've been trying to track down all the 3D models I used for the build to print up spares. In a few cases I can't actually find the original file anywhere! Not sure what to do about that, as I thought I'd been tracking everything fairly well, with consistent naming and versioning. A few small things I had to re-model, or I'm stuck with just the generated g-code and I can't really edit it anymore.

With some plastics with art on them, I figured the mismatched drop targets stood out a bit, so I made some quick stickers for them

In a bunch of places I had holes in the playfield where I'd installed features and then removed them later, so I'd just taped some paper over them, but that was also a bit ugly.
Luckily, I had some scans of the playfield from before I'd cut many of the holes, so I printed out stickers of the wood grain and covered them up

As more playtesting got done, I started having issues with a few connectors falling out of stuff. Usually I'd used connectors with latches/ramps to prevent that, but in some cases I couldn't. So I 3D printed some little braces to hold stuff in

I did a bunch of little quality of life things in the code. Hold start to end game. Tweaks to a lot of switches. More instructional text. A lot more feedback as stuff is happening, like these little blinks when you hit something to help you know it wasn't a near miss or something

Posted Tuesday, November 16, 2021
at 11:49 AM

Tags: Blog Post, Pinball, Project, P3,

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