Sunday, October 28, 2018

homebrew isn't cheap

So one thing me and Hugh from OPP can definitely agree on is parts aren't cheap, and playfield BOM's can really get out of hand quickly.  Individually parts don't seem expensive, but when you start adding them up (bulb sockets, any sub-assembly with coils) it can really add up.  Honestly many homebrew guys ends up spending 2-3 times as much money making their own game than what it would cost a pinball manufacturer to build one (because of volume of parts).  This is the reason why Hugh grabs populated playfields when he comes across them, the parts are worth more than the whole.  I mean really look at any sub-assembly on pinball life.  Each flipper assembly is $40, each sling assembly is $40, each drop target assembly is $50.  And this isn't a knock against Terry, far from it.  I think the idea that you can buy these assemblies is great for someone that doesn't want to scrounge parts from another game.  If you look at all the parts, there's a lot of cost in there (both in formed metal, assembly, etc).  Now it's not like Pinball life designed these and said "hey, that's the price".  No, he effectively had existing parts reverse engineered, bought them in volume, and his employees build them up as needed.  If you were to try to buy the individual parts and make them yourself, you'd actually spend more money than buying the assembly.  Not that it makes much sense (less assembly, cheaper), but that's often how things work out.

When you see pinball manufacturers being conservative on mechs in the last 5-10 years, there's probably a good reason for that.  Other than Stern, nobody really has the volume buying power.  I think Stern is plagued by several overhead issues.  They have a giant building (110,000 square feet) that has to be powered, lit, heated/cooled, insured, maintained.  They have a TON of employees not only designing games but building them.  Then there's the licensing, and not just the ones they do something with (buying a license for future use to make sure nobody else makes that game is money out the window).  But just look at Beatles which is practically identical to Seawitch (add a magnet and a spinner which are mechs that already exist).  Unlike Seawitch (with basic coding for rules and numerical scoring) it will have deep rules and full color LCD animations that need programming.  Beyond that, it's rumored the Beatles license (including the measly 5 songs) cost them a million dollars.  So if they plan on selling a total of 1,964 (we'll see how well it sells), that's really only an additional $500 amortized into each machine's BOM.  I'm hearing numbers like $7500 for the bottom gold edition, $12.5k for the platinum edition, and $25k for the diamond edition (no extra features for upper tiers either) which is clearly a cash grab.  You might say "oh well, if there's not much offered in higher tiers, clearly they will sell mostly gold editions and the higher tiers just won't sell".  You'd be wrong.  Not only are they screwing their customers, they are also screwing their distributors if what I'm hearing is true.  Distributors have to buy packages.. IE if you want a few gold editions, you must also buy the higher tiers in order to get those.  It'd be like if you were a car dealer that just wants base model camry's, but toyota won't sell you just base models.  You MUST stock the high end camry's too.

So anyway, without sounding like a JPOP of re-inventing the wheel (he made things custom for the sake of being custom).  In my case, I want to cost reduce parts to make pinball more affordable (not more expensive by requiring buyers to order a custom sheet of glass).  Recently I started coming up with a concept to cost reduce standup targets.  I'm still contemplating the best way to do it, but once I get a design I like I'm absolutely going to pursue getting them made.  Whether it be just selling it to the homebrew community, or if a smaller pinball company likes the idea I'm happy to sell to whoever wants them.  Now standup targets aren't terribly expensive (about $6 each), but again.. Start throwing a couple rows of 5-bank and you're quickly up to $60.  There really isn't much to it, but because we are still using those antiquated brass leaf switches with tungsten contacts and fiberglass spacers they are still pricey.  When I was deep in my homebrew projects, I felt strongly about replacing the leaf switches on the flipper buttons with tactile switches.  It has a better feeling of that spring snap, and micro switches never need adjustment, plus today they are dirt cheap.  I actually did a cost estimate (not including labor), and I could easily get the cost of a standup target to around $1 depending on if I cut brackets from aluminum channel or 3d printed a bracket (which is still low cost, but less labor).

Cherry switches are REALLY cheap if you know where to shop around.  I bought some really tiny ones about a month ago to play around with that can handle 1A.  Though they are so small that they are hard to design around.  The holes themselves are like 1.8mm (which means you are really using tiny screws).


I recently made an order for some slightly larger ones rated at 5A that also include one of those roller wheels (which should help eliminate wear as the edge of the switch blade rubs against the back of the target).


The difference in price?  The first one can be bought for 50 cents each in quantity of 10 (US seller).  If you're buying from China, 7 cents each.  The second nicer switch is also 50 cents each in quantity 10 (US Seller), or 10 cents each if you order from China.  Since I plan to use a bunch of these I ordered 10 from the US seller so I can get them quicker, and 20 switches from China where I don't care if they take 3-4 weeks to get here.

So I started looking at the $50 drop target assembly.  You have a $10 coil, a $5 leaf switch, a bunch of zinc plated bent steel, it all starts to really add up.  Coils are used everywhere in pinball because that's what they started to use to make flippers flip back in 1948 and they just kept using them.  For things like flippers and slings, absolutely there's no other cost effective way that can get those to move quickly with a lot of torque.  I see no reason why drop targets need to be so quick (other than coils are what have always been used because they were available).  Even if they were half the speed of coils, you'd hardly notice the difference.  Also coiled drop targets are really loud when a large bank of them reset.  Whether that be individual inline banks, or a wide bank that is reset by a single coil because of the mechanism required to raise them all back up at the same time.

Now I believe the first pinball to use a servo (in the true sense of an off the shelf enclosed servo) is the blinder mech on the Data East Tommy (1994) followed by the turning head on Sega Frankenstein.  One could argue the rotating head on party zone is a servo, but in reality it's a 12v motor attached to a gear reduction gearbox.  So while it has properties of a servo, it's a motor and gearbox and not cheap by any means.  It's unclear if the homer head in simpsons pinball party is servo based from the manual.  However, it does seem like Stern has at least moved to cherry switches for their drop target banks (but still uses a coil to reset).

Looks like Pinball Life does sell a Stern 3-bank drop assembly, but it's not clear if it includes switches (and it's friggen expensive at $199!)

I mean if I had to estimate the cost of that assembly I'd say it probably costs about $20 in parts.

So where does that leave me?  Well designing my own mech of course.  I played around in solidworks this weekend on and off and came up with the mech below:

It consists of a custom 3d printed target, a custom 3d printed sleeve/bracket (which allows the cheap roller switch to be mounted), and a servo.  The cheapest servo I could find on hobby king is $2.35:

So my BOM consists of:
$2.35 - servo
$.10 - cherry switch
$.04 - two screws for switch
$.08 - two screws to mount servo
$.10 - Target (cost of PLA to print)
$.26 - mounting bracket (cost of PLA to print)
$.10 - servo arm
-----------------------------
$3.03 per assembly

If we're doing math, that's approximately 16 times cheaper than an equivalent single drop target.  What does that mean for homebrew?  Well if it's robust enough (time will tell), it means if I'm only budgeting for 3 inline drop targets ($150), I can now put nearly 50 drop targets in my game for the same cost and not compromise the design because parts are too expensive.


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