# Homebrew Showcase: Black Knight Pinball AI Tech Build by Rolando Martin

**Source:** Marco Pinball  
**Type:** video  
**Published:** 2025-11-07  
**Duration:** 14m 55s  
**Beat:** Pinball

**URL:** https://www.youtube.com/watch?v=dcA0hME7_AY

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## Analysis

Rolando Martin showcases a homebrew Black Knight pinball machine at Pinball Expo 2025 PinDev Con, notable not for the game itself but for his custom-designed electronics system. Martin, an electronics engineer from Winnipeg, developed a port multiplier system using Raspberry Pi that dramatically simplifies homebrew control by utilizing unused processor capacity, eliminating the need for expensive multi-board setups. The system features optical target detection instead of mechanical switches, custom-designed components (epoxy-cast lenses, 3D-printed targets), and intelligent power management that can identify failed transistors at the component level—capabilities exceeding some commercial systems.

### Key Claims

- [MEDIUM] Mission Pinball Framework (MPF) running on Raspberry Pi only uses 25% of available processor capacity, leaving 75% unused — _Rolando Martin explaining his design motivation; technical claim about MPF and Raspberry Pi architecture_
- [HIGH] Standard Raspberry Pi GPIO provides only 23 ports, insufficient for typical machine needs (16 solenoids + 42-45 switches) — _Rolando Martin, technical specification of Raspberry Pi limitations_
- [MEDIUM] The system can theoretically support up to 64 input bits and 64 output bits without signal degradation — _Rolando Martin discussing system scalability_
- [MEDIUM] Optical sensing with monostable circuit is superior to mechanical lift switches because it eliminates bounce without requiring software debouncing — _Rolando Martin explaining technical advantages of his optical system design_
- [HIGH] The power board monitors individual transistor current and can automatically identify which transistor has failed — _Rolando Martin describing power management diagnostics_
- [MEDIUM] Spike system can shut down if power gets problematic, but cannot identify failures at component level — _Manu and Rolando comparing to commercial Spike system (note: Rolando admits he doesn't fully know Spike's capabilities)_
- [MEDIUM] A major distributor has already contacted Rolando about commercializing the system — _Rolando Martin stating 'some major distributor has contacted me' and 'there may be plans'_
- [HIGH] The entire Black Knight build uses only two main boards: Raspberry Pi 3 and a port multiplier board — _Rolando Martin describing hardware architecture_

### Notable Quotes

> "The reason that this game is here is not because of the game itself...the reason the game is here is because I developed a whole electronic system that helps home brewers control their machines in a way that is super simple and super economical."
> — **Rolando Martin**, early section
> _Core motivation for the showcase—the electronics innovation, not the game tribute_

> "Everybody's using MPF—Mission Pinball Framework. And the Raspberry Pi can only do one processor at a time running Python...And so I thought, well, there's 75% of the Raspberry Pi power that is not being used. They only use 25%. What if you tap into the remaining 75% power?"
> — **Rolando Martin**, mid section
> _Core technical insight driving the entire system design_

> "I use a lot of software and a lot of hardware to make things simpler."
> — **Rolando Martin**, power management section
> _Design philosophy statement summarizing his approach to complexity reduction_

> "So if you use a Pi 5—which is insane. You have two screens of 4K each."
> — **Rolando Martin**, scalability discussion
> _Demonstrates system scalability to newer Raspberry Pi hardware_

> "It's not only the system—it's the whole ecosystem: the target board, the targets, the bumpers, the slingshots. Everything has been made to feed the system."
> — **Rolando Martin**, commercialization section
> _Indicates comprehensive design approach beyond just control electronics_

### Entities

| Name | Type | Context |
|------|------|---------|
| Rolando Martin | person | Electronics engineer from Buenos Aires, Argentina; resident of Winnipeg, Canada for 21 years; designer of custom Raspberry Pi-based pinball control system; homebrew builder |
| Manu | person | Host/presenter at Pinball Expo 2025 PinDev Con for Marco Pinball content |
| Steve Ritchie | person | Classic pinball designer, cited as Rolando's idol; designed Black Knight 2000 |
| Larry DeMar | person | Classic pinball designer, cited as Rolando's idol |
| Black Knight | game | Classic Williams pinball machine; subject of Rolando's homebrew tribute build showcasing his electronics system |
| Pinball Expo 2025 | event | Annual pinball industry show in Chicago; PinDev Con (homebrew section) is where this showcase took place |
| Raspberry Pi | product | Single-board computer platform; Raspberry Pi 3 used in this build; core technology for Rolando's control system |
| Mission Pinball Framework (MPF) | product | Open-source pinball machine control framework; Python-based; standard tool for homebrew builders; referenced as inefficient in Raspberry Pi implementation |
| Spike System | product | Commercial pinball machine control system by Stern; referenced for power management and failure detection comparison |
| Jersey Jack Pinball | company | Pinball manufacturer; referenced as having complex hardware requirements that might push system limits |
| Marco Pinball | organization | Content creator/YouTube channel producing this video |

### Topics

- **Primary:** Homebrew pinball electronics design, Raspberry Pi-based control systems, Port multiplexing and signal management, Optical vs. mechanical switch technology, Power management and diagnostics
- **Secondary:** Black Knight tribute and classic pinball design, Commercialization and ecosystem development
- **Mentioned:** Pinball Expo 2025 PinDev Con homebrew showcase

### Sentiment

**Positive** (0.88) — Host and guest convey enthusiasm about the technical innovation. Rolando is passionate and articulate about his design; Manu is impressed and encouraging. No criticism or negative sentiment expressed. Tone is celebratory of engineering achievement and potential impact on homebrew community.

### Signals

- **[design_innovation]** Novel port multiplier system leverages unused Raspberry Pi processor capacity to eliminate need for expensive multi-board commercial systems; reduces component count to two main boards (confidence: high) — Rolando's detailed technical explanation of port multiplier, virtual ports, and daisy-chain architecture; comparison to conventional MPF/Ethernet-based systems
- **[technology_signal]** Custom optical target detection system using monostable circuits replaces traditional mechanical lift switches; claims superior reliability and eliminates bounce issues (confidence: high) — Rolando describes optical system: 'these rollovers, they trigger an optical system that detects when the little plastic comes down it interrupts a beam of light'
- **[manufacturing_signal]** Homebrew builder has designed and manufactured custom components including epoxy-cast lenses and posts, 3D-printed targets, and silicon rubber elements (confidence: high) — Rolando: 'I designed everything that you see here...even the lenses of the machine are made with poured epoxy cast epoxy...and the posts are made with cast epoxy...targets are 3D printed'
- **[product_strategy]** Rolando has designed comprehensive ecosystem including control boards, target boards, bumpers, and slingshots as integrated components rather than point solution (confidence: high) — Rolando: 'It's not only the system—it's the whole ecosystem: the target board, the targets, the bumpers, the slingshots. Everything has been made to feed the system.'
- **[business_signal]** Major distributor(s) have contacted Rolando about commercializing the system; plans are in motion but not yet publicly detailed (confidence: medium) — Rolando: 'some major distributor has contacted me about the system, and there may be plans'
- **[community_signal]** System positions itself as more accessible and economical alternative to existing homebrew control solutions (MPF/FAST boards/P-ROC) that may intimidate new builders (confidence: medium) — Manu: 'has a system here for home brewers who maybe feel a little more intimidated about getting an entire Mission Framework and FAST boards and or P-ROC'
- **[event_signal]** Innovation highlighted at Pinball Expo 2025 PinDev Con, the primary industry venue for homebrew and emerging technology in pinball (confidence: high) — Video content explicitly from Pinball Expo 2025 PinDev Con homebrew section
- **[technology_signal]** Custom power board with microprocessor-controlled current monitoring can identify failed transistors at component level, providing granular diagnostics beyond typical commercial systems (confidence: high) — Rolando: 'every time that you see something weird, like a transistor has shorted, it stops everything...and it tells you which of the transistors [has broken]...can detect which transistor has broken'
- **[product_concern]** System is Raspberry Pi-specific and may face scaling challenges with more complex modern commercial pinball hardware; Jersey Jack titles specifically mentioned as potentially problematic (confidence: medium) — Rolando: 'my system is only compatible with the Raspberry Pi, right?' and when asked about Jersey Jack: 'Jersey Jack has some very very wild stuff...I don't know what kind of power they need'

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## Transcript

We're here at Pinball Expo 2025 Pind DevCon the homebrew section. My name is Manu and today today now we have got another pin here. Black Knight by Rolando or just say Rolando. That's it. Rolando fine.
Where are you from?
I am originally from uh Bonosides, Argentina. And I have been living in Canada for the last 21 years.
Why? No, I'm just kidding. [laughter]
Why? I am in in Winnipeg. Even in Winnipeg, which is very cold.
You actually went to the cold. All right.
A lot of jokes about Winnipeg.
Yeah. Yeah, the Simpsons, they even have a they're driving into Winnipeg and they all of a sudden they have a sign that says, "We were born here. What's your excuse?"
Yeah, that's right. That's right. I forgot about that. Um, tell us a little about about your game and and and why is this a unique Black Knight?
So, uh, the reason the reason that the game is here is not because of the game itself. Uh, the game is really a tribute to, uh, Steve Ritchie and Larry Dear that were my idols when I was growing up. I did play a lot of other games, particularly the Black Knight. I really uh love the Black Knight. I spent days and days in the arcade playing.
Yeah.
So, um the reason that this game is here is because I developed a whole electronic system that helps home brewer control uh their machines in a way that is super simple and super economical. So I when I started with the idea of making a game, I look at all the options and I saw that many of these uh uh systems that were commercially available, they kind of rely on a computer that connects to a USB port and it connects to a bunch of electronics. And I was looking at that and I'm electronics engineer myself and I was thinking why they go to all that and Raspberry Pi has four processors and then I start to look into the information that I see and turns out that they everybody's using MPF mission pinball.
Sure. Yeah. Or something else. And the Raspberry Pi can only do one processor at a time running Python, which MPF is is written on Python. And so I I thought, well, there's 75% of the Raspberry Pi Raspberry Pi power that is not being used. They only use 25%. What if you tap into the remaining 75% power? And that's how I came up with a system that multiplies the ports that you have. The GPIOs of the the RA Pi that you have available are only 23. So then I came up with a what I call yeah I called it the port multiplier. I mean 23 GPIO ports are not enough for run machine. Just think about the solenoids. You have 16 solenoids. So right off the bat you have 16 outputs and the inputs of the of the system you have at least uh I don't know like 42 45 switches. Yeah. So then you have to you need a means to multiply it and I I I sort of designed a board that I thought it actually it simplifies uh a lot everything because you only have one system and you have a bunch of virtual ports. Uh you don't when you do the program the electronics does that for you. You don't see that you see a vector that you see ones and zeros there and those are your virtual ports. This machine has uh six 8bit virtual ports and also in the electronics you have uh every port I call them ports right okay uh you have a connector that has 10 pins uh one is for ground the other is for uh uh power and then you have eight bits and that's I call them the bus the port bus and then the wiring is very simple because with that rebon cable that you connect to the port you visit device device device device in a daisy chain manner And then on each one of the devices, you select in which bit of the of the of the of the bus or the port, you're going to drop you're going to drop your signal. Right. So there, for instance, if you look at the at the uh the pop bumper, it has only one bit that tells Yeah. The pop bumper has only one bit that tells when the skirt is actuated.
Right.
Right. Uh on the drop targets, you have three bits that tells you when each drop target is activated. And the same thing in the lock of the three bolts of the black knight. Uh it's another device. So and then because I take pleasure on making things on my own, I design everything that you see here. I designed not only the electronics, I designed the playfield. I designed the even even the uh the lenses of the machine are made with a por epoxy cast epoxy and the posts are made with cast epoxy. I made silicon rubbers for all that. Yeah. And
so are you saying this?
And the target
the drop drop targets too. Is that not your own design?
They Yes, they are 3D printed actually and the everything also is optical in the system. Uh there is no nothing is lift switches because I don't like lip switches
really.
So these rollovers they trigger opt uh
they trigger an optical system that detects when the uh when the little plastic comes down it interrupts a beam of light
and that has also a little electronic circuit which is very easy to make. This is called monostable and gives you a very nice perfect pulse opposite to when you make a contact between two uh metal por metal thingies uh on a lift switch right that makes a lot of bouncing it's called and you have to debounce right so there's software that goes into that so I make it much more [music] simple
so this looks like a uh a standard uh uh uh playfield uh w with uh are these the original graphics
well the graphics are original I didn't want to change anything because uh my tribute to Stevie and and to uh and to Larry and to the guy that designed the artwork. I don't remember the name. Uh but I think I wanted to keep it original, the original design uh but show what you can do with the electronics that I designed. It's only really two boards. And this is a Raspberry Pi driven. It's Yeah, there's a Raspberry Pi a Pi Y a Raspberry Pi 3, right? The Raspberry Pi Yeah, the Raspberry The Raspberry Pi 3.
Old school Raspberry Pi for an old school pinball machine. Yes, exactly. The Raser Pi3 connects to a port multiplier board. Like I was mentioning, the port multiplier board has six input ports and two output ports. The output ports connect directly to a couple of boards that I call the twins because they're tiny and they look each other. Uh they're uh and they are cute. So, and then those those uh 8bit uh uh solenoid boards, they control the 16 solenos on the machine, right? So, um, and also the Raspberry Pi has a beautiful 32 inch screen output. This the screen
Oh, that's right. The screen is the out. Oh, that's that's right.
That's not a translate.
No, no, that's not a translite.
It's also not the what the VPX would call a a direct B2S because this is not running on Windows.
It's running on uh I think it's Rasbian.
Yes.
Uh from Raspberry Pi and uh it does a pretty good job. like I'm using the full potential of the Raspberry Pi. I'm using the four process of the Raspberry Pi. So you don't need additional uh hardware other than the poor multipliers, right? So I mean uh in other systems you will see that they are interconnected with a lot of Ethernet cables and they have all these communication protocols and the boards talk to each other and they try to I guess they try to overcome all the electromagnetic interference that you have in a playfield uh by using the Ethernet which is a very good system for RJ45. uh yes the RJ45 but also the RJ45 has eight uh wires and each one of each pair is twisted pairs and they have the differential signal and that is kind of the technology that is immune to noise right that's why they use that but having said that that the noise electromagnetic noise is going to affect very fast moving signals for a very slow moving signals it doesn't really affect that much and what you have here because of the port multiplication uh the ports are ones and zero that change over time uh at the speed of what a human can see, right? So you drop a target, but the one drops to zero. I mean, you hit the bumper like you have 300 milliseconds that the thing is down and goes up. So it really not affected by the noise. So you don't need really something really expensive, okay, than that. So I have some of the boards. Unfortunately, I have my boards uh the sample boards that I left on my on my stand. Uh but I can show you later if you want. Uh it is really a 10 cm by 10 cm uh which is in American would be 4 in by 4 in. Uh
I I I hate imperial metric. I love metric system.
So yeah. So it's a yeah that is the size of the port multiplier only 10 cm by 10 cm uh four uh in x 4 in that hooks hook up to the Raspberry Pi. The twins are only uh I think 6 cm by by 4 cm. It only has the uh the fed transistors that drive the solenoids. And also I I developed a power board which is a power filter that is controlled also by a microprocessor that is all the time reading the current.
So every time that you see something weird like a transistor has shorted it stops everything. It opens the 48 vol. It displays a message on the screen and it tells you I one of the transistors and and and you can run a routine, a very smart routine that uh close closes and opens all the transistors one at a time to check the current changes and it can detect which of the transistor has broken.
So that's actually that's actually more than the spike system can do cuz the spike system can tell if the power gets wacky and shut the whole board down. But you have it down to the
well I I don't know
to the fat.
I don't know what the spike does. It sounds to me that they should be able to
at some point in time. I think I I look at their at their schematics and I think that they use a current sensor.
What I use is a current sensor that checks all the current of all the machine. It doesn't look at the individual current of each solenoid. Uh and the reason is just economics. I got got away with it because I can uh I can just use uh the whole current that the machine is consuming and I can tell when there's something went wrong using my programming and algorithms and uh that's what I'm saying. I I can uh I use a lot of uh software
and a lot of hardware to make things simpler. So let let so let me ask you what is there a a limit to what you've developed in terms of like uh uh comparable games like so Black Knight admittedly is a a little more um
it's dated
a little more dated. Yeah. But will your stuff be able to run say like the current like Jersey Jack stuff?
Will Jersey Jack has some very very wild stuff?
Yeah, they do a lot of stuff under there. So I I don't know uh what the kind of power they need to do that. So I mean I'd say to to use my system my system is only compatible with the Raspberry Pi, right?
So because it multiplies the ports of the Raspberry Pi period, right?
So if you use a Riy 5.
Sure. There you go.
Which is insane. You have two screens of 4K each.
All right. So and you can do a lot of things with that.
So you can scale up your
your stack. you can definitely scale it up as long as as the Raspberry Pi scales up. Now, if you get to the point that uh the multiplication of the ports is not enough I I mean you can multiply then uh much more times as long as your signals go become slower and slower. All right? Because of the sampling rate. uh right now without any uh uh degradation to what you see here, you could have 64 uh input bits
and 64 output bits. So that means 64 um uh inputs for uh signals that come from the playfield and 64 solenoids that you can control.
That's a lot. So who the hell needs 64 solenoids?
Yeah, that that's [laughter] so and then again it goes it goes again to the concept of the output port. You have a port that that serves to you that puts eight bits on a on a right and you connect to that port and you you can use the twins, right? Or you can use a twin and a half, you can use three of the a bit solenoid boards and and then you can control 24 solenoids, right? Or you can control uh 32 solenoids. Uh that depends how many output ports you use. But also you can use the output port to control some other things. You can control stepper motors. Yeah, you can
control topper stuff. You can control whatever whatever you want you can control.
H how is this available for people to use? How do people get in touch with you to talk
talk to about or or is that in your plans at all?
No, it's in the plan. It's there's already something in motion. Okay.
You can send me an email if you want to know about more about the system right now.
What is your email address?
It's uh my name and my last name. It's Rolando Martin uh atgmail.com. my name r o l a n d o m a r t i ngmail.com I hope that went clear and uh all right and uh yeah they can send me an email I can tell you everything about the system I cannot say much more but uh some major distributor has contacted me about the system and there may be plans because it's not only the system it's the whole ecosystem is the target board is the targets is the bumpers is the slingshots everything has been made uh to feed the system. Well, this is really exciting. Orlando has a system here for home brewers who maybe uh feel a little more intimidated about getting an entire, you know, mission framework and fast boards and or pock. Um it looks like the system here is capable of running many many many ideas and and pinball layouts and stuff like that. Like Rando here said, who's going to need 64 solenoid? What? Who's going to need 64 solenoids? If you need 64, if you need 65 solenoids, you're doing it wrong. [laughter]
Okay, you may need more than 64 inputs.
Yeah, inputs. Yes, but if they are slow inputs, like drop targets are very slow inputs, uh you can you can keep multiplying the ports, right? I mean, if somebody comes with a crazy idea,
uh we can we can study it
and then we can we can develop whatever they need. It's going to be really exciting to see what you continue with Rolando. Thank you so much. You guys saw it right here. This is Black Knight running completely on Rolando system. Nothing else.
Thank you so much.
Thank you so much, man. Thank you for having me. It was a pleasure. All right. And
I hope a lot of success with this with your endeavors.
Get in touch with this guy if you need to. Thanks, guys.

_(Acquisition: youtube_auto_sub, Enrichment: v1)_

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*Exported from Journalist Tool on 2026-04-13 | Item ID: d3b808af-e2c5-4195-8a0d-43929cbd3d59*