Playfield :: Hardware :: Flippers

If you are contemplating building your own machine, then you probably already know a good bit about how pinball machines work. It’s basically series of electro-mechanical events where a steel ball activates a switch, which in turn fires a solenoid that drives a mechanism, sending the ball off in some other direction where it most likely hits another switch, and so on and so on…

The Flippers are the only real interface to the game: You manually activate a switch that fires a solenoid, which then drives the flipper mechanism… The issue that becomes apparent with Flippers is that you want high-power (and high current) when you’re hitting the ball, but you don’t want to burn out your flipper coils if you hold the buttons too long. These problems have been solved during the long evolution of Pinball, with somewhat complicated results.

It’s understandable that there are often questions about connecting and firing Flippers; With their double-wound coils, multiple recirculation diodes, and end-of-stroke (EOS) switches, it’s easy to get confused if you’re hooking them up for the first time. And to make things more complex, today’s modern control systems have the ability to do many more things, like fire the “power” and “hold” coils independently, apply “patter” to the coils, feed the EOS switch into the controller as a normal switch, or even bypassed it completely.

I’m not going to make a case for what is the best way, but I will elaborate on each of the pro’s and con’s and let you decide what works best for your own Custom Pinball Machine…

Background on the standard 70’s- or 80’s-style setup:

Most early games fired the Flippers directly off of the cabinet flipper buttons, using high-power contact switches. In addition to this, there was some sort of relay in series with the circuit that could enable and disable the flippers between games, or even between balls. Here’s a diagram of a standard vintage-style setup:

Pinball Flipper Relay Circuit

Typical vintage circuit for enabling pinball flipper mechs.

And typical vintage-style EOS switch setup and function:

Pinball EOS switch

Typical End-of-Stroke switch setup and function.

In the above diagram, the EOS switch is Normally Closed (NC) before activation. The switch is shorting out the “Hold” coil, which is a higher resistance and would otherwise limit the current. One the Flipper has reached full stroke, the EOS switch opens, adding the “Hold” coil to the circuit. This reduces the current while maintaining enough of an electro-magnetic field to keep the solenoid in position. On a side note, the typical convention for labeling coils is to indicate the wire gauge, followed by the number of turns. So “25-500” is 500 turns of 25Ga magnet wire. The hold coil is labeled “34-4500”, so 4500 turns of 34Ga magnet wire. Low gauge is thicker wire, with less resistance and higher current carrying ability. Resistance also increases with length. So more turns at a higher gauge will yield a much higher resistance than fewer turns at a lower gauge, even if the same amount of copper is used.

Speaking from personal experience, about half of my Custom Pinball games use this type of setup. The specific relay (and corresponding socket) that I have used to enable the flippers can be found here:


Pinball flipper relay

Standard K10 form-factor relay, DPDT suitable for pinball.

K10 relay socket for Pinball

Typical K10 relay socket with terminal connections.

You have a couple of options in wiring up this circuit. I like to have the relay on the high-voltage side of the flipper coils, and use the cabinet buttons to switch the ground side of the coil.

If you’re interested in using this old-school method, or possible have scavenged parts from vintage machines, here are a couple links that describe how these older circuits work, and how to properly repair older Flippers:

Old-school Advantages:

Zero latency from button push to firing the flippers. And, only one solenoid driver channel is used, just for the relay.

Old-school Disadvantages:

As simple as the circuit is, it can be a lot of wiring to get power, ground, buttons, flippers, and solenoid driver lines all to a central relay. Power of the flippers are not independently adjustable.

Variations on the Old-school circuit:

From a power supply standpoint, one concern with flippers is that their high-power coils produce large current surges (see the previous blog post for more info on power supplies). This could become a problem particularly on multiple-flipper games. However, I have wired four-flipper games in parallel without any issues. If it is a concern when building your own Custom Pinball Machine,  there are clever variants that uses the EOS switches to stagger the firing of the upper and lower flippers. The advantage being that the surge current is spread out over time, so each flipper gets the full power available. Primary flipper requires a DPST leaf-switch, circuit diagram here:

Firing multiple pinball flippers.

Staggered firing of multiple flipper coils using the primary EOS switch, reduces surge current.

Modern Systems:

If you’re building a Custom Pinball Machine, the controllers and drivers available today allow for independent firing of both the “power” and  “hold” coils, or they can adjust the duty cycle of the voltage to the solenoid so that only a single “power” coil is needed. The EOS switch can be used to tell the controller to go to a much lower duty-cycle, or the EOS switch can be bypassed completely and a timer function used instead to switch to a low-power mode. This modern technique uses PWM, sometimes called “patter”. Here is a good breakdown of the various methods that can be used today:

Modern Advantages:

It’s much easier to wire flippers directly to the driver, and have cabinet buttons go to the controller. I currently have two Custom Pinball Machines wired this way, and I can see how the ease of wiring justifies the downsides. Plus, you have full control over flipper power, and could even manipulate the power as part of the game rules.

Modern Disadvantages:

Having the Flipper buttons sent to the controller, and then the controller signal sent to the driver, can introduce latency (that is, a significant delay between pushing the button and seeing something happen). This is by far the most commonly cited disadvantage. However, I can say from personal experience that it’s barely noticeable (or not detectable at all), even with a relatively low-speed controller like an Arduino. With that said, there are other potentially more critical disadvantages… Eliminating the EOS circuit is not “Fail Safe”. Having the high-power coil under computer control could lead to problems, especially during development and testing, or as a machine gets older and less reliable.

Another disadvantage is that configurations firing two coils per Flipper (independant “power” and “hold”) can eat up available driver channels pretty quickly, especially on multi-flipper games. But this would only be a corner case where the EOS switch was eliminated, while retaining the “hold” coil (as in situations where PWM “patter” drive is not an option).

Where to Buy:

Aside from eBay, and especially if you want new hardware, the best places to buy Pinball Flipper Mechs are from Marco Specialty or Pinball Life:

Reproduction Bally Flipper Mech

Reproduction Bally Flipper Mech available from Pinball Life.


Reproduction Stern Flipper Mech from Marco Specialties




Control :: Electronics :: Power Supplies

This one is going to be a little bit controversial if you’re an old-school pinball person, but I’m going to make the case for using off-the-shelf switching power supplies for your Custom Pinball Machine…

Here are the specific ones that I have used in the last four games that I’ve built:

Typical switching power supply suitable for Custom Pinball.

Typical switching power supply suitable for Custom Pinball.

Obviously both made by Lamda, one is 36V nominal for solenoid coils (32V – 40V adjustable) at 4.3A output, and the other is 5V nominal for lighting and control electronics (4.7V – 5.5V adjustable). These are typical closed-frame power supplies used in industrial equipment.

I usually set the higher voltage supply to about 38V, which is plenty for flippers, and can drive the heavier loads like resetting drop-target banks. I also usually boost the lower voltage to 5.5V (or 6V even if you use a different version) to add a little extra punch to the lighting. Most of the 5V components either have their own 5V regulators on-board (and thus may require a slightly higher voltage), or can tolerate a slight boost.

Here are some points to help justify this decision, and convince the die-hard transformer crowd:

  • Most games these days only require two different voltages, and thus the cost savings of an all-in-one multi-tap transformer are no longer realized. Older Solid-State games had as many as five different voltages…
  • Most people now use LED lighting, at much lower currents. Older games with incandescent lights had huge power draws, and required large supplies. General illumination was the main energy consumer in older games.
  • The idea of having lots of continuous current available for driving solenoids is counter-intuitive. Most older machines fused their 43VDC power at 5A max. Having excessive current available only makes it more likely to burn out solenoids (or fuses if you’re lucky). A power-limited supply makes it virtually impossible to burn out a coil.
  • Most games will usually only have one- or two solenoids firing at any one time. In my games, 4A at 38V is more than enough to fire four flipper coils simultaneously…
  • Modern switching power supplies are smaller, more efficient, and not as noisy as their earlier counterparts. In the old days, designers avoided switchers because of conducted noise issues at the high power required for older games.
  • Large capacitors are easier to get these days, and can better compensate for surges that previously had to be mitigated by going to higher power ratings.

Buying an off-the-shelf industrial power supply is not only convenient, it can also be cheaper than some of the custom- or purpose-built “pinball” power supplies available, which are usually overkill for what is actually needed.


Control :: Electronics :: Solenoids

This is a follow-up to the original post on controlling solenoids with a Pinball Controller’s “Power Driver 16” board. I’m adding some photos to aid with the wiring and assembly, as well as giving a few troubleshooting tips.

Power Driver 16

Overview showing the Power Driver 16 and the Mini RS-485 Master

Click through to see a larger image. This is an overview of the Power Driver 16 and Mini RS-485 Master, showing the inputs, Mini Master output, and connection to the solenoid driver.

Mini Master RS-485

Detail of the Mini Master connections.

Click through to see a larger image. This detail shot shows the inputs to the Mini Master: Orange wire is Power (5V), Blue wire is TX from the Arduino, Black is GND. The outputs of the Mini Master are: White for TX(+) and Black for TX(-).

Power Driver 16 detail

Detail of the RS-485 lines running to the solenoid driver.

This is a detail showing the Mini Master output coming in on the Pinball Controller’s Power Driver 16 port labeled J9. Pin one is Serial +, which gets the White TX(+) wire, and pin 2 is Serial-, which gets the Black TX(-) wire from the Mini Master.

Arduino SPI RS-485

Arduino connection of the SPI interface to the Mini Master RS-485 converter.

Click through for full size image. This shows the Arduino SPI interface to the Mini Master RS-485 converter. It is a three-wire connection, with 5V power, signal and ground.

Arduino Uno pinout

Arduino pinout showing SPI interface pins.


SPI interface uses the GND, MOSI and 5V pins when connecting to the Mini Master RS-485 converter.

Control :: Arduino :: Code

I’ve updated the downloads page (here) with Arduino code for the Game Master Controllers, as well as code for the PinScore Controllers and the Test Circuits.

The Game Master Controllers can be used as-is, or (more likely), as a template for creating your own games. Some are more complicated than others, but they’ve all been recently updated with a common, stable code. They should all have the capability to do multi-player (with the right build-switches set), and the “Miss Adventure” code is designed to to Multi-ball.

Each game has it’s own PinScore controller code. However, Jupiter Crush is the most advanced, so probably would make the best template.

There is also code to test switches, displays and solenoid drivers.


Cabinet :: Design :: Head

This Pinball Head design is one that I’ve used on all three of my Custom Pinball Machines, and will work with the lower-angled retro-looking cabinets, as well as the steeper multi-level ones. The head has a thinner profile than older games, mainly because less room is needed for electronics and wiring. The angled trim pieces, however, keep the vintage look.

Head assembly CAD model

SolidWorks screenshot of of Head assembly.

This SolidWorks model is available on the downloads page, as well as DXFs and SVGs of the templates you see here.

Custom Pinball Head

Diagram of individual parts for the Head, along with assembly views.

Above is a diagram of the parts needed to make the head, along with assembly views. These pieces are cut from either 1×4 or 1×6 pine, which is easy to find at your local hardware store. The light board is 1/2″ plywood, but doesn’t need to be the same high quality as the playfield. A piano hinge is used to attach the light board to the head, allowing access to the back. My preference for score displays is to use vintage brackets, which I’ve included in the template as an example.

Cabinet with Head

Extra trim parts and brackets needed to complete Cabinet assembly and Head attachment.

There are several extra trim pieces needed to complete the Cabinet and Head assembly. A piece of 1×4 pine stock is cut down to 2.375 wide, and serves to fill the gap between the head and cabinet, as well as act as a corner brace for the rear corners. A 1.75″ long block of 2×2 pine (which is really 1.5″x 1.5″) is used to locate and support the leg bracket during assembly, and also serves as corner reinforcement.

Cabinet :: Design :: Templates

My most recent Custom Pinball Machine utilized a multi-level playfield, which requires the steeper slope you typically see on more modern cabinets. I’ve posted templates for this design for those that are either looking for a modern feel, or need the extra headroom for flying wire-forms or alpha-ramps (or just an old-school upper level playfield).

I call this latest pin “Miss Adventure”, so all the files will have the initial MA right after the date code. These can all be found on the download page. Please understand ahead of time that the Cabinet depth is designed to work with Gottlieb lockdown bar hardware, and a Custom Head (template for this to follow in the next post).

Note that, as in the previous post, the front corners are intended to be mitered for a high-quality professional look. If you’re not going to do this step for whatever reason, be sure to take off an extra 3/4″ cut (indicated by the blue dash in the SVG and DXF files), but only take this off either 1) front of both left and right side pieces (preferred) or 2) both edges of the front piece (less-preferred).

SolidWorks ScreenShot

This is a SolidWorks screenshot for a two-level Custom Pinball Cabinet

This template is designed to be mostly cut from a single sheet of 4’x8′ plywood, 3/4″ thick. Birch top is usually relatively cheap while providing a quality finish. Some other minor pieces are needed, which I usually cut from pine stock. I’ll detail this in the next post related to the Head fabrication.

Plywood template for Custom Pinball Cabinet

Template for cutting Custom Cabinet pieces from a single sheet of 4’x8′ Birch plywood.


Cabinet :: Fabrication :: Miter

If you decide to go the route of building a Custom Pinball Cabinet from scratch, one of the biggest fabrication challenges you will face is how to get clean looking corners…

Most of the cabinet edges will either be covered with some form of trim, or not visible except from the bottom or from the back. The features that can’t escape attention, however, are the two vertical edges of the front panel on either side of the coin door. For a professional-looking quality Cabinet, these two corners will need some form of mitered edge, and the feature of choice for Pinball Cabinets has been to use a “Miter-Lock”.

The front vertical edges of the Cabinet are the most visible, and need a mitered edge in order for the Cabinet to have a clean professional look.

The front vertical edges of the Cabinet are the most visible, and need a mitered edge in order for the Cabinet to have a clean professional look.

A Miter-Lock edge is created on a router table with a single Miter-Lock Bit, with the two panels of wood being passed through the cutter either laying flat or standing vertical. Below are a set of images showing a typical Miter-Lock Bit installed in a bench-top router table:

Miter Lock Bit

Typical “Miter-Lock Bit” installed in a bench-top router table.

The bit itself is like a typical 45 deg cutter, but with two distinct jogs in the middle. These jogs create self-interlocking edges when two pieces of plywood are cut horizontally and vertically.

The panels that need the Miter-Lock are the two sides (front-edge only), and the front panel (both side edges). Since the side panels are very large and unwieldily, it makes more sense to run these flat through the router, and run the smaller front panel vertically. See the pics below:

Run the small, easer to handle, front panel through the cutter vertically.

Run the small, easer to handle, front panel through the cutter vertically.

Running the front panel through the cutter vertically (above), and the side panel through flat (below), creates a mirror cut that is self-locking.

Larger cabinet side panel being run through the router flat, cutting the front vertical edge.

Larger cabinet side panel being run through the router flat, cutting the front vertical edge.

When done correctly, the Miter-Lock Bit will cut two mirror-image edges, creating a self-interlocking corner. This process should only be done by those who are experienced with the equipment and use of a router table. Aside from the typical set-up, the important adjustments for this cut are to get both the height and offset equal and matched to the thickness of your wood panel (in this case, 3/4″ 7-layer plywood).

Any mis-adjustment in height or offset will cause one edge to stick out farther than the other. Not a disaster, but does’t look as nice and could cause the overall dimensions of the cabinet to be skewed.

Below are a couple images showing how each of the finished edges should look, and how they fit together:


Example of how each Miter-Lock cut looks, and how the two edges fit together to create a self-locking joint.

Example of how each Miter-Lock cut looks, and how the two edges fit together to create a self-locking joint.

One final tip I have is how to avoid having the vertical edge chip out during the routing process. Now, in a perfect world, we would have the grain of the wood running vertical along the cut line. But, because our side panels are just longer than 48″, it’s not possible to lay out the whole cabinet in one sheet when the typical grain runs length-wise. (Stay tuned for updates, I’m working on a slightly more compact cabinet that will rotate the layout to match the grain).

Below are a panel of images depicting a method that avoids the thin top laminate from chipping out during the vertical cut:

To avoid having the top laminate chip-out, you can pre-score the cut line with an xacto knife.

To avoid having the top laminate chip-out, you can pre-score the cut line with an xacto knife.

Here are the steps to avoid chip-out (the first panel is an example of the disastrous results of cutting across the grain…):

  1. Using a same-thickness piece of plywood as a guide, line up a straight-edge ruler 3/4″ away from the outside edge. Bear in mind that the face of the panel we are cutting is the inside, the “beauty” side should be face-down.
  2. Clamp straight-edge to the panel, preferably at both ends, and preferably to the table as well.
  3. Using an Xacto knife, cut along the edge through the to laminate layer. This will be about 1/16″ depending on what grade your using.

Tip: The metal straight-edge is to the inside of the cut line. This means if you make a slight mistake with the Xacto, you’re only messing up a surface that will later be removed. It’s best to use a new, sharp blade, but with a new blade you always need to make your first cut with a VERY light hand, and then come back with several passes to get the cut deeper. It is very easy to get of track with a new blade.

Good Luck and Be Safe!




Playfield :: Hardware :: Posts

Playfield Posts are essentially an evolution of the original “pins” that gave us the name “Pinball”.

The modern Playfield Post comes in three main styles, and many colors. Since you are building a Custom machine, and not a restoration or reproduction, you have the freedom to chose which style and color to use, and there are several artistic considerations. But first, here are some examples of what is available today:



Plastic Molded Post Types:

  • Faceted – These were used fairly early on a lot of Bally and Stern games, usually molded in red.
  • Finned – These are slightly more modern, used on a lot of Bally / Williams games.
  • Star – Less popular, but still available today.




Artistic Considerations:

There are several things to consider when choosing a post design that will effect the overall look of the games. The questions you should ask yourself when making these creative decisions are:

  • How the post looks in direct or ambient light?
  • How the post looks when lit from behind?
  • What type of light goes it project onto the playfield?



Playfield :: Electronics :: Switches

Switches are probably the single-most important device on a Pinball Playfield, and are fundamental to the game itself. The entire Pinball Machine is essentially an electro-mechanical interaction, with the switch being the all-important middle-man between the ball and the active mechanisms…

Switches also pre-date a lot of the other devices we commonly associate with Pinball, like Flippers, Thumpers, Slingshots, etc. and most machines today still use some manner of the traditional wire-form activated leaf-switch we find on older games.

The focus of this blog is on solid-state based Custom Pinball Machines, and one advantage with SS when it comes to switches is that they can be scanned as a matrix. Most SS games since the 70’s have used this technique. With matrix scanning, you can read 40 switches with 5 drive lines and 8 read lines (5×8 = 40), but only use 13 digital I/Os (5+8 = 13). And just to hammer home the math, that saves 27 I/Os (40-13 = 27), putting this in the wheelhouse of a small micro-controller board like the Arduino Uno.

The Layout.

Here’s a typical schematic (below) of a switch matrix from a standard Bally 70’s solid-state (SS) game. I present this because it will serve us well even today since the principles are the same.

Switch matrix schematic

Schematic of a switch matrix designed to be scanned by solid-state electronics. For our Custom Pinball Machine, we will use a micro-controller like the Arduino Uno.


Scanning The Matrix:

In the case above, there are five drive lines and eight sense lines, which we will model for our own design. The process of scanning works like this:

  • All the drive lines are initially held low.
  • The first drive line is switched high.
  • Each of the eight sense lines are read.
  • These values then represent the state of switches 1 thru 8.
  • The first line returns low, and the second line goes high.
  • Again, read in the eight sense lines.
  • These values become the state of switches 9 thru 16.
  • And so on until all 40 switch states are read…

Notice that each switch in the schematic has a diode on the drive side. This prevents “ghosting” in the case of multiple switches being active at the same time. Without it, the current from one drive column could back-feed through any switches active on the same row, in essence driving a second (unintended) column. An active switch on the second column would create a “ghost” activation on the first (real) drive column.

Below is a spreadsheet I usually create during the design of the game, and reference for the assembly and wiring.

Switch matrix excel spreadsheet

Excel spreadsheet showing switch signal names with drive wire colors and sense line colors.

Most older games made use of two-color striped wire, so there was never a duplicate color combination for any signal. In our case, it’s more feasible to use a limited set of standard colors, and just keep track of where there might be duplicates.

I always create a chart like this early on, giving the switches logical names and grouping them based roughly on where they will be located on the playfield. It helps to use the same name later in the Arduino code that will be doing the scanning.

The Switch.

Almost all older games use leaf-switches connected to a wire-form for activation. These usually have three contacts, and the diode mentioned above is mounted directly on the switch. This make wiring easier and more mechanically stable.


Custom Pinball Switch

This is a typical “spoon” switch used to activate Thumpers. There is a built-in diode, with the drive wire coming in on the positive side (yellow), and a sense wire on the negative side (orange).

The Code.

Below can be cut-and-pasted into an Arduino project. Use this for testing and diagnostics, or as a reference for creating your own game code.

There are several features to this code aside from just scanning the switch matrix, hopefully it will become clear as you read though it:

  • The code compares the previous state of the switch to the current state to determine if the state is “new”
  • It then rotates the state for the next loop so that current becomes previous.
  • It only call the state “new” if it went low-to-high, you can change this in your own code.
  • It implements a de-bounce timer function, which is adjustable, or just comment it out.
  • Prints the “new” switch state to the serial monitor when switch is activated.
// --------------------------------------------

This code will scan a 5x8 switch matrix and print the status of new switch states.


  -  Set the first drive line output.
  -  Scan first input.
  -  If state was low, and now high, set new switch flag.
  -  Send message out to Serial Monitor (optional).
  -  Loop through all eight inputs.
  -  Loop through all five drive lines.
  -  Delay.
  -  Repeat.
For questions or comments, check the blog:


//  --------------------------

//  --------------------------
unsigned char j = 0;	//
unsigned char i = 0;	//
unsigned char k = 0;	//

//  --------------------------
unsigned char switchStateNow[40];	// start no digit selected
unsigned char switchStatePrev[40];	// start no digit selected
unsigned char switchNew[40];	//
unsigned char switchDebounce[40];
// --------------------------
// optional for this test code, but good idea
// if you are going to build on this as a game later.
SWITCH_A, // was 1
SWITCH_B, // was 2
SWITCH_C, // was 3
SWITCH_D, // was 4


SWITCH_LANE_DROP_3, // kicker / shoot again




#define SWITCH_DEBOUNCE_DURATION 10 //10 loops

void setup() 
  pinMode(14,OUTPUT); // analog in used a row drive out
  //pinMode(18,OUTPUT); // if only using four drive lines, no need to set this

  pinMode(2,INPUT); // analog in used a row drive out
  pinMode(3,INPUT); // analog in used a row drive out
  pinMode(4,INPUT); // analog in used a row drive out
  pinMode(5,INPUT); // analog in used a row drive out
  pinMode(6,INPUT); // analog in used a row drive out
  pinMode(7,INPUT); // analog in used a row drive out
  pinMode(8,INPUT); // analog in used a row drive out
  pinMode(9,INPUT); // analog in used a row drive out

  digitalWrite(2,LOW); // pull up on
  digitalWrite(3,LOW); // pull up on
  digitalWrite(4,LOW); // pull up on
  digitalWrite(5,LOW); // pull up on
  digitalWrite(6,LOW); // pull up on
  digitalWrite(7,LOW); // pull up on
  digitalWrite(8,LOW); // pull up on
  digitalWrite(9,LOW); // pull up on

  Serial.begin(9600);           // start serial for output

//  --------------------------
  for (j = 0; j < 40; j++) 
    switchStateNow[j] = 1; //
    switchStatePrev[j] = 1;//
    switchNew[j] = 0;
    switchDebounce[j] = 100;
} // end setup

void loop() 
  //  *****************************************
  //  -----------------------------------------
  //             START READ SWITCH
  //  -----------------------------------------
  //  *****************************************  

  for (j = 1; j < 5; j++) 
    // START ALL LOW (no signal)
    digitalWrite(14, LOW); // pins 14-17
    digitalWrite(15, LOW); // pins 14-17
    digitalWrite(16, LOW); // pins 14-17
    digitalWrite(17, LOW); // pins 14-17    

    digitalWrite((j+13), HIGH); // pins 14-17

    delayMicroseconds(400) ;
    for (i = 0; i < 8; i++) 
      switchStatePrev[((j*8) + i)] = switchStateNow[((j*8) + i)]; // rotate variable
      switchStateNow[((j*8) + i)] = digitalRead(i + 2); // pins 2-9

      // check for a "new" state
      if ((switchStateNow[((j*8) + i)] == switchStatePrev[((j*8) + i)]) || (switchDebounce[((j*8) + i)] > 0))
      if ( switchStateNow[((j*8) + i)] == switchStatePrev[((j*8) + i)]) 
        switchNew[((j*8) + i)] = 0; // same as old
      } // end if
      else // must be new if not old and new equals one
        if (switchStateNow[((j*8) + i)] == 1)
          switchNew[((j*8) + i)] = 1; // new
          #if (DEBOUNCE_MODE)
            switchDebounce[((j*8) + i)] = SWITCH_DEBOUNCE_DURATION; // set timer
          #if (SERIAL_MONITOR == 1)
            Serial.print("Switch = ");
            Serial.print((j*8) + i); // TODO check this formatting later
      } // end else
    } // end for i
  } // end for j    

    for (j = 0; j < 40; j++) 
      if (switchDebounce[j] > 0) 
        switchDebounce[j] -= 1; // ramp down to zero

  delay(10) ; // 10ms loop time
  // end read switches

//return;// end MAIN LOOP



Cabinet :: Electronics :: Display

In recent years, reproduction components and other products have surfaced to help repair and restore vintage pinball machines. Some of these reproductions make use of the latest technology internally, essentially a re-design that is more reliable than the original. One case in point is the Classic LED Pinball Display from PinScore. We can take advantage of the great work being done on the restoration side, leveraging this market to create our Custom Pinball Machines. But in this case, we need some way to easily interface these devices to whatever control system we happen to be using. Which is the subject of today’s post…

PinScore display

PinScore makes reproduction displays, using the latest technology for higher reliability.

PinScore Display:

If you’re building a four-player game, you can buy a set of these for a little bit of a discount. I usually purchase from Marco Specialties Pinball Parts when I can, a direct link to the products you’ll need can be found here:

PinScore display custom pinball machine

An Arduino can be used to drive a PinScore display, while also communicating serially with a game controller.

Arduino Uno:

The Maker community has already discovered that the Arduino series of boards is an easy and inexpensive way to get into programming with micro controllers. Here are links to get you started:

The Arduino IDE is a free software download, with a large support community, and can be downloaded here.

PinScore display custom pinball machine

Detail shot of Arduino showing connections and pinouts.

Using the parts list above, you should have everything you need to connect the PinScore to the Arduino as shown above and below.

PinScore display custom pinball machine

Detail showing connection side of PinScore with header pinout to Arduino.

I’ve provided some test code at the bottom of the page that can be cut-and-pasted into an Arduino project. The photo below shows the display being mounting into the front of the light board, with the test numbers “123456” loaded. The Arduino project is set up to use the Serial interface, which for diagnostic purposes can be accessed over the same USB programming plug, and the Serial Monitor built into the Arduino IDE.

PinScore display custom pinball machine

Display mounted from the front into a standard Bally score bracket.

Below shows all the displays installed, waiting for the backglass.

PinScore display custom pinball machine

Finished installation showing all five displays and the lit up back-board.

The Arduino code below can be used as a reference in your own controller, or directly as a diagnostic test tool. The procedure to test a unit is as follows:

  • Plug your target board (with PinScore display attached) into your computer via USB.
  • Power the PinScore with external 5V supply.
  • Download the program to the target.
  • Open the Serial Monitor built into the IDE Tools.
  • Type “$pinXyyyyyy” and press return, where X is the number you assigned the display (i.e. player 4), and yyyyyy is the number or score you want to display. For example, “$pin4123456” is what I typed in to display what is in the photos above.
  • If your score is less that six digits, use an underscore. For example, “$pin4_98765” will display the number 98765, with the first digit being blank.
  • If you have a fifth display for Balls/Credits, you would sent something like “$pin5_03_10” for Ball = 3 and Credits = 10.

Arduino code here.

Cut and paste text into a new project, then download to your target device.


Using the serial monitor, type in the header "$PIN" followed by the ID you've chosen
for the PinScore display (ie, 1, 2, 3, 4 etc), and then the actual score for that unit.

EXAMPLE: Typing in "$PIN4100000" to the serial monitor and hitting return should read
the score "100000"  player four's display.

For questions or comments, check the blog:


String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete
unsigned char selectDigit = 0;	// start no digit selected
const unsigned char selectLatch = 12;	// start no digit selected
unsigned char cDataPinScore[8];
unsigned char cPinScore = 4;
unsigned char digitBCD = 0;	// start no digit selected

#define ASCII_A 65
#define ASCII_B 66
#define ASCII_C 67
#define ASCII_D 68
#define ASCII_E 69
#define ASCII_F 70
#define ASCII_G 71
#define ASCII_H 72
#define ASCII_I 73
#define ASCII_J 74
#define ASCII_K 75
#define ASCII_L 76
#define ASCII_M 77
#define ASCII_N 78
#define ASCII_O 79
#define ASCII_P 80
#define ASCII_Q 81
#define ASCII_R 82
#define ASCII_S 83
#define ASCII_T 84
#define ASCII_U 85
#define ASCII_V 86
#define ASCII_W 87
#define ASCII_X 88
#define ASCII_Y 89
#define ASCII_Z 90
#define ASCII_EQUAL 61
#define ASCII_DOLLAR 36
#define ASCII_COMMA 44
#define ASCII_CR 13
#define ASCII_LF 10


#define LED_CHAN PLAYER_ONE // change this to the PLAYER that the unit will be driving

void setup() 
  DDRB = B00111111;  // sets Arduino port B pins 0 to 4 as outputs
  DDRD = B11111111;  // sets Arduino port B pins 0 to 4 as outputs

  // initialize serial:

  // reserve 200 bytes for the inputString:

    for (int i = 0; i < 8; i++) 
    cDataPinScore[i] = i + 48;


void loop() 

// continuously scan the PinScore display, outputing the most recent data
  for (int i = 2; i < 8; i++) 
    selectDigit = i;  

    PORTD = (0); // clear all


    PORTB = (cDataPinScore[i-2]- 48); // subracting 48 converts an ASCII char to its equivalent int


    delay(3) ;// hold each digit for a period


  SerialEvent occurs whenever a new data comes in the
 hardware serial RX.  This routine is run between each
 time loop() runs, so using delay inside loop can delay
 response.  Multiple bytes of data may be available.

void serialEvent() 
  while (Serial.available()) 
    // get the new byte:
    char inChar = (char);

    // add it to the inputString:
    inputString += inChar;

    // if the incoming character is a newline, set a flag
    // so the main loop can do something about it:
    if (inChar == '\n') 
      int inputLength = inputString.length();

      if (inputString[0] == ASCII_DOLLAR) // check for header
        cPinScore = inputString[4]; // PinScore id held here

        if (cPinScore == (LED_CHAN + 48)) //4 )
          for (int k = 0; k<6; k++) // acount for numbers less than six digits
  	  cDataPinScore[k] = inputString[k + 5];
  	  } // next k

        } // end If received ID matches the one this unit is programmed for

        stringComplete = true;
        inputString = "";

      } // end If first char was $ 

    } // end If new line 

  } // end While// end Sub