An I/O controller for virtual pinball machines: accelerometer nudge sensing, analog plunger input, button input encoding, LedWiz compatible output controls, and more.

Dependencies:   mbed FastIO FastPWM USBDevice

Fork of Pinscape_Controller by Mike R


This is Version 2 of the Pinscape Controller, an I/O controller for virtual pinball machines. (You can find the old version 1 software here.) Pinscape is software for the KL25Z that turns the board into a full-featured I/O controller for virtual pinball, with support for accelerometer-based nudging, a real plunger, button inputs, and feedback device control.

In case you haven't heard of the concept before, a "virtual pinball machine" is basically a video pinball simulator that's built into a real pinball machine body. A TV monitor goes in place of the pinball playfield, and a second TV goes in the backbox to serve as the "backglass" display. A third smaller monitor can serve as the "DMD" (the Dot Matrix Display used for scoring on newer machines), or you can even install a real pinball plasma DMD. A computer is hidden inside the cabinet, running pinball emulation software that displays a life-sized playfield on the main TV. The cabinet has all of the usual buttons, too, so it not only looks like the real thing, but plays like it too. That's a picture of my own machine to the right. On the outside, it's built exactly like a real arcade pinball machine, with the same overall dimensions and all of the standard pinball cabinet hardware.

A few small companies build and sell complete, finished virtual pinball machines, but I think it's more fun as a DIY project. If you have some basic wood-working skills and know your way around PCs, you can build one from scratch. The computer part is just an ordinary Windows PC, and all of the pinball emulation can be built out of free, open-source software. In that spirit, the Pinscape Controller is an open-source software/hardware project that offers a no-compromises, all-in-one control center for all of the unique input/output needs of a virtual pinball cabinet. If you've been thinking about building one of these, but you're not sure how to connect a plunger, flipper buttons, lights, nudge sensor, and whatever else you can think of, this project might be just what you're looking for.

You can find much more information about DIY Pin Cab building in general in the Virtual Cabinet Forum on Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.


  • Pinscape Release Builds: This page has download links for all of the Pinscape software. To get started, install and run the Pinscape Config Tool on your Windows computer. It will lead you through the steps for installing the Pinscape firmware on the KL25Z.
  • Config Tool Source Code. The complete C# source code for the config tool. You don't need this to run the tool, but it's available if you want to customize anything or see how it works inside.


The new Version 2 Build Guide is now complete! This new version aims to be a complete guide to building a virtual pinball machine, including not only the Pinscape elements but all of the basics, from sourcing parts to building all of the hardware.

You can also refer to the original Hardware Build Guide (PDF), but that's out of date now, since it refers to the old version 1 software, which was rather different (especially when it comes to configuration).

System Requirements

The new config tool requires a fairly up-to-date Microsoft .NET installation. If you use Windows Update to keep your system current, you should be fine. A modern version of Internet Explorer (IE) is required, even if you don't use it as your main browser, because the config tool uses some system components that Microsoft packages into the IE install set. I test with IE11, so that's known to work. IE8 doesn't work. IE9 and 10 are unknown at this point.

The Windows requirements are only for the config tool. The firmware doesn't care about anything on the Windows side, so if you can make do without the config tool, you can use almost any Windows setup.

Main Features

Plunger: The Pinscape Controller started out as a "mechanical plunger" controller: a device for attaching a real pinball plunger to the video game software so that you could launch the ball the natural way. This is still, of course, a central feature of the project. The software supports several types of sensors: a high-resolution optical sensor (which works by essentially taking pictures of the plunger as it moves); a slide potentionmeter (which determines the position via the changing electrical resistance in the pot); a quadrature sensor (which counts bars printed on a special guide rail that it moves along); and an IR distance sensor (which determines the position by sending pulses of light at the plunger and measuring the round-trip travel time). The Build Guide explains how to set up each type of sensor.

Nudging: The KL25Z (the little microcontroller that the software runs on) has a built-in accelerometer. The Pinscape software uses it to sense when you nudge the cabinet, and feeds the acceleration data to the pinball software on the PC. This turns physical nudges into virtual English on the ball. The accelerometer is quite sensitive and accurate, so we can measure the difference between little bumps and hard shoves, and everything in between. The result is natural and immersive.

Buttons: You can wire real pinball buttons to the KL25Z, and the software will translate the buttons into PC input. You have the option to map each button to a keyboard key or joystick button. You can wire up your flipper buttons, Magna Save buttons, Start button, coin slots, operator buttons, and whatever else you need.

Feedback devices: You can also attach "feedback devices" to the KL25Z. Feedback devices are things that create tactile, sound, and lighting effects in sync with the game action. The most popular PC pinball emulators know how to address a wide variety of these devices, and know how to match them to on-screen action in each virtual table. You just need an I/O controller that translates commands from the PC into electrical signals that turn the devices on and off. The Pinscape Controller can do that for you.

Expansion Boards

There are two main ways to run the Pinscape Controller: standalone, or using the "expansion boards".

In the basic standalone setup, you just need the KL25Z, plus whatever buttons, sensors, and feedback devices you want to attach to it. This mode lets you take advantage of everything the software can do, but for some features, you'll have to build some ad hoc external circuitry to interface external devices with the KL25Z. The Build Guide has detailed plans for exactly what you need to build.

The other option is the Pinscape Expansion Boards. The expansion boards are a companion project, which is also totally free and open-source, that provides Printed Circuit Board (PCB) layouts that are designed specifically to work with the Pinscape software. The PCB designs are in the widely used EAGLE format, which many PCB manufacturers can turn directly into physical boards for you. The expansion boards organize all of the external connections more neatly than on the standalone KL25Z, and they add all of the interface circuitry needed for all of the advanced software functions. The big thing they bring to the table is lots of high-power outputs. The boards provide a modular system that lets you add boards to add more outputs. If you opt for the basic core setup, you'll have enough outputs for all of the toys in a really well-equipped cabinet. If your ambitions go beyond merely well-equipped and run to the ridiculously extravagant, just add an extra board or two. The modular design also means that you can add to the system over time.

Expansion Board project page

Update notes

If you have a Pinscape V1 setup already installed, you should be able to switch to the new version pretty seamlessly. There are just a couple of things to be aware of.

First, the "configuration" procedure is completely different in the new version. Way better and way easier, but it's not what you're used to from V1. In V1, you had to edit the project source code and compile your own custom version of the program. No more! With V2, you simply install the standard, pre-compiled .bin file, and select options using the Pinscape Config Tool on Windows.

Second, if you're using the TSL1410R optical sensor for your plunger, there's a chance you'll need to boost your light source's brightness a little bit. The "shutter speed" is faster in this version, which means that it doesn't spend as much time collecting light per frame as before. The software actually does "auto exposure" adaptation on every frame, so the increased shutter speed really shouldn't bother it, but it does require a certain minimum level of contrast, which requires a certain minimal level of lighting. Check the plunger viewer in the setup tool if you have any problems; if the image looks totally dark, try increasing the light level to see if that helps.

New Features

V2 has numerous new features. Here are some of the highlights...

Dynamic configuration: as explained above, configuration is now handled through the Config Tool on Windows. It's no longer necessary to edit the source code or compile your own modified binary.

Improved plunger sensing: the software now reads the TSL1410R optical sensor about 15x faster than it did before. This allows reading the sensor at full resolution (400dpi), about 400 times per second. The faster frame rate makes a big difference in how accurately we can read the plunger position during the fast motion of a release, which allows for more precise position sensing and faster response. The differences aren't dramatic, since the sensing was already pretty good even with the slower V1 scan rate, but you might notice a little better precision in tricky skill shots.

Keyboard keys: button inputs can now be mapped to keyboard keys. The joystick button option is still available as well, of course. Keyboard keys have the advantage of being closer to universal for PC pinball software: some pinball software can be set up to take joystick input, but nearly all PC pinball emulators can take keyboard input, and nearly all of them use the same key mappings.

Local shift button: one physical button can be designed as the local shift button. This works like a Shift button on a keyboard, but with cabinet buttons. It allows each physical button on the cabinet to have two PC keys assigned, one normal and one shifted. Hold down the local shift button, then press another key, and the other key's shifted key mapping is sent to the PC. The shift button can have a regular key mapping of its own as well, so it can do double duty. The shift feature lets you access more functions without cluttering your cabinet with extra buttons. It's especially nice for less frequently used functions like adjusting the volume or activating night mode.

Night mode: the output controller has a new "night mode" option, which lets you turn off all of your noisy devices with a single button, switch, or PC command. You can designate individual ports as noisy or not. Night mode only disables the noisemakers, so you still get the benefit of your flashers, button lights, and other quiet devices. This lets you play late into the night without disturbing your housemates or neighbors.

Gamma correction: you can designate individual output ports for gamma correction. This adjusts the intensity level of an output to make it match the way the human eye perceives brightness, so that fades and color mixes look more natural in lighting devices. You can apply this to individual ports, so that it only affects ports that actually have lights of some kind attached.

IR Remote Control: the controller software can transmit and/or receive IR remote control commands if you attach appropriate parts (an IR LED to send, an IR sensor chip to receive). This can be used to turn on your TV(s) when the system powers on, if they don't turn on automatically, and for any other functions you can think of requiring IR send/receive capabilities. You can assign IR commands to cabinet buttons, so that pressing a button on your cabinet sends a remote control command from the attached IR LED, and you can have the controller generate virtual key presses on your PC in response to received IR commands. If you have the IR sensor attached, the system can use it to learn commands from your existing remotes.

Yet more USB fixes: I've been gradually finding and fixing USB bugs in the mbed library for months now. This version has all of the fixes of the last couple of releases, of course, plus some new ones. It also has a new "last resort" feature, since there always seems to be "just one more" USB bug. The last resort is that you can tell the device to automatically reboot itself if it loses the USB connection and can't restore it within a given time limit.

More Downloads

  • Custom VP builds: I created modified versions of Visual Pinball 9.9 and Physmod5 that you might want to use in combination with this controller. The modified versions have special handling for plunger calibration specific to the Pinscape Controller, as well as some enhancements to the nudge physics. If you're not using the plunger, you might still want it for the nudge improvements. The modified version also works with any other input controller, so you can get the enhanced nudging effects even if you're using a different plunger/nudge kit. The big change in the modified versions is a "filter" for accelerometer input that's designed to make the response to cabinet nudges more realistic. It also makes the response more subdued than in the standard VP, so it's not to everyone's taste. The downloads include both the updated executables and the source code changes, in case you want to merge the changes into your own custom version(s).

    Note! These features are now standard in the official VP releases, so you don't need my custom builds if you're using 9.9.1 or later and/or VP 10. I don't think there's any reason to use my versions instead of the latest official ones, and in fact I'd encourage you to use the official releases since they're more up to date, but I'm leaving my builds available just in case. In the official versions, look for the checkbox "Enable Nudge Filter" in the Keys preferences dialog. My custom versions don't include that checkbox; they just enable the filter unconditionally.
  • Output circuit shopping list: This is a saved shopping cart at with the parts needed to build one copy of the high-power output circuit for the LedWiz emulator feature, for use with the standalone KL25Z (that is, without the expansion boards). The quantities in the cart are for one output channel, so if you want N outputs, simply multiply the quantities by the N, with one exception: you only need one ULN2803 transistor array chip for each eight output circuits. If you're using the expansion boards, you won't need any of this, since the boards provide their own high-power outputs.
  • Cary Owens' optical sensor housing: A 3D-printable design for a housing/mounting bracket for the optical plunger sensor, designed by Cary Owens. This makes it easy to mount the sensor.
  • Lemming77's potentiometer mounting bracket and shooter rod connecter: Sketchup designs for 3D-printable parts for mounting a slide potentiometer as the plunger sensor. These were designed for a particular slide potentiometer that used to be available from an seller but is no longer listed. You can probably use this design as a starting point for other similar devices; just check the dimensions before committing the design to plastic.

Copyright and License

The Pinscape firmware is copyright 2014, 2021 by Michael J Roberts. It's released under an MIT open-source license. See License.

Warning to VirtuaPin Kit Owners

This software isn't designed as a replacement for the VirtuaPin plunger kit's firmware. If you bought the VirtuaPin kit, I recommend that you don't install this software. The VirtuaPin kit uses the same KL25Z microcontroller that Pinscape uses, but the rest of its hardware is different and incompatible. In particular, the Pinscape firmware doesn't include support for the IR proximity sensor used in the VirtuaPin plunger kit, so you won't be able to use your plunger device with the Pinscape firmware. In addition, the VirtuaPin setup uses a different set of GPIO pins for the button inputs from the Pinscape defaults, so if you do install the Pinscape firmware, you'll have to go into the Config Tool and reassign all of the buttons to match the VirtuaPin wiring.

--- a/TLC5940/TLC5940.h	Sat Sep 26 02:15:59 2015 +0000
+++ b/TLC5940/TLC5940.h	Wed Oct 21 21:53:07 2015 +0000
@@ -20,6 +20,50 @@
 #ifndef TLC5940_H
 #define TLC5940_H
+// Should we do the grayscale update within the blanking interval?
+// If this is set to 1, we'll send grayscale data during the blanking
+// interval; if 0, we'll send grayscale during the PWM cycle.
+// Mode 0 is the *intended* way of using these chips, but mode 1
+// produces a more stable signal in my test setup.
+// In my breadboard testing, using the standard data-during-PWM
+// mode causes some amount of signal instability with multiple
+// daisy-chained TLC5940's.  It appears that there's some signal
+// interference (maybe RF or electrical ringing in the wires) that
+// can make the bit data and/or clock prone to noise that causes
+// random bits to propagate down the daisy chain.  This happens
+// frequently enough in my breadboard setup to be visible as
+// regular flicker.  Careful wiring, short wire runs, and decoupling
+// capacitors noticeably improve it, but I haven't been able to 
+// eliminate it entirely in my test setup.  Using the data-during-
+// blanking mode, however, *does* eliminate it entirely.
+// It clearly should be possible to eliminate the signal problems
+// in a well-designed PCB layout, but for the time being, I'm
+// making data-during-blanking the default, since it provides
+// such a noticeable improvement in my test setup, and the cost
+// is minimal.  The cost is that it lengthens the blanking interval
+// slightly.  With four chips and the SPI clock at 28MHz, the 
+// full data update takes 27us; with the PWM clock at 500kHz, the 
+// grayscale cycle is 8192us.  This means that the 27us data send 
+// keeps the BLANK asserted for an additional 0.3% of the cycle 
+// time, which in term reduces output brightness by the same amount.
+// This brightness reduction isn't noticeable on its own, but it
+// can be seen as a flicker on data cycles if we send data on
+// some blanking cycles but not on others.  To eliminate the
+// flicker, the code sends a data update on *every* cycle when
+// using this mode to ensure that the 0.3% brightness reduction
+// is uniform across time.
+// When using this code with TLC5940 chips on a PCB, I recommend
+// doing a test: set this to 0, run the board, turn on all outputs
+// (connected to LEDs), and observe the results.  If you don't
+// see any randomness or flicker in a minute or two of observation,
+// you're getting a good clean signal throughout the daisy chain
+// and don't need the workaround.  If you do see any instability, 
+// set this back to 1.
 #include "mbed.h"
 #include "FastPWM.h"
 #include "SimpleDMA.h"
@@ -27,10 +71,16 @@
   * SPI speed used by the mbed to communicate with the TLC5940
   * The TLC5940 supports up to 30Mhz.  It's best to keep this as
-  * high as the microcontroller will allow, since a higher SPI 
-  * speed yields a faster grayscale data update.  However, if
-  * you have problems with unreliable signal transmission to the
-  * TLC5940s, reducing this speed might help.
+  * high as possible, since a higher SPI speed yields a faster 
+  * grayscale data update.  However, I've seen some slight
+  * instability in the signal in my breadboard setup using the
+  * full 30MHz, so I've reduced this slightly, which seems to
+  * yield a solid signal.  The limit will vary according to how
+  * clean the signal path is to the chips; you can probably crank
+  * this up to full speed if you have a well-designed PCB, good
+  * decoupling capacitors near the 5940 VCC/GND pins, and short
+  * wires between the KL25Z and the PCB.  A short, clean path to
+  * KL25Z ground seems especially important.
   * The SPI clock must be fast enough that the data transmission
   * time for a full update is comfortably less than the blanking 
@@ -49,7 +99,7 @@
   * isn't a factor.  E.g., at SPI=30MHz and GSCLK=500kHz, 
   * t(blank) is 8192us and t(refresh) is 25us.
-#define SPI_SPEED 3000000
+#define SPI_SPEED 2800000
   * The rate at which the GSCLK pin is pulsed.   This also controls 
@@ -116,15 +166,19 @@
-          nchips(nchips),
-          newGSData(true)
+          nchips(nchips)
-        // Set initial output pin states - XLAT off, BLANK on (BLANK turns off
-        // all of the outputs while we're setting up)
+        // set XLAT to initially off
         xlat = 0;
+        // Assert BLANK while starting up, to keep the outputs turned off until
+        // everything is stable.  This helps prevent spurious flashes during startup.
+        // (That's not particularly important for lights, but it matters more for
+        // tactile devices.  It's a bit alarming to fire a replay knocker on every
+        // power-on, for example.)
         blank = 1;
-        // allocate the grayscale buffer
+        // allocate the grayscale buffer, and set all outputs to fully off
         gs = new unsigned short[nchips*16];
         memset(gs, 0, nchips*16*sizeof(gs[0]));
@@ -137,6 +191,22 @@
         // format 0.
         spi.format(8, 0);
+        // Send out a full data set to the chips, to clear out any random
+        // startup data from the registers.  Include some extra bits - there
+        // are some cases (such as after sending dot correct commands) where
+        // an extra bit per chip is required, and the initial state is 
+        // somewhat unpredictable, so send extra just to make sure we cover
+        // all bases.  This does no harm; extra bits just fall off the end of
+        // the daisy chain, and since we want all registers set to 0, we can
+        // send arbitrarily many extra 0's.
+        for (int i = 0 ; i < nchips*25 ; ++i)
+            spi.write(0);
+        // do an initial XLAT to latch all of these "0" values into the
+        // grayscale registers
+        xlat = 1;
+        xlat = 0;
         // Allocate a DMA buffer.  The transfer on each cycle is 192 bits per
         // chip = 24 bytes per chip.
@@ -160,6 +230,10 @@
         // Configure the GSCLK output's frequency
+        // mark that we need an initial update
+        newGSData = true;
+        needXlat = false;
     // Start the clock running
@@ -236,55 +310,43 @@
     // Has new GS/DC data been loaded?
     volatile bool newGSData;
+    // Do we need an XLAT signal on the next blanking interval?
+    volatile bool needXlat;
     // Function to reset the display and send the next chunks of data
     void reset()
         // start the blanking cycle
-        // If we have new GS data, send it now
-        if (true)
-        {
-            // Send the new grayscale data.
-            //
-            // Note that ideally, we'd do this during the new PWM cycle
-            // rather than during the blanking interval.  The TLC5940 is
-            // specifically designed to allow this.  However, in my testing,
-            // I found that sending new data during the PWM cycle was
-            // unreliable - it seemed to cause a fair amount of glitching,
-            // which as far as I can tell is signal noise coming from
-            // crosstalk between the grayscale clock signal and the 
-            // SPI signal.  This seems to be a common problem with
-            // daisy-chained TLC5940s.  It can in principle be solved with
-            // careful high-speed circuit design (good ground planes, 
-            // short leads, decoupling capacitors), and indeed I was able
-            // to improve stability to some extent with circuit tweaks,
-            // but I wasn't able to eliminate it entirely.  Moving the
-            // data refresh into the blanking interval, on the other 
-            // hand, seems to entirely eliminate any instability.
-            //
-            // update() will format the current grayscale data into our
-            // DMA transfer buffer and kick off the DMA transfer, then
-            // return.  At that point we can return from the interrupt,
-            // but WITHOUT ending the blanking cycle - we want to keep
-            // blanking the outputs until the DMA transfer finishes.  When
-            // the transfer is complete, the DMA controller will fire an
-            // interrupt that will trigger our dmaDone() callback, at 
-            // which point we'll finally complete the blanking cycle and
-            // start a new grayscale cycle.
+        // We're configured to send the new GS data entirely within
+        // the blanking interval.  Start the DMA transfer now, and
+        // return without ending the blanking interval.  The DMA
+        // completion interrupt handler will do that when the data
+        // update has completed.  
+        //
+        // Note that we do the data update/ unconditionally in the 
+        // send-during-blanking case, whether or not we have new GS 
+        // data.  This is because the update causes a 0.3% reduction 
+        // in brightness because of the elongated BLANK interval.
+        // That would be visible as a flicker on each update if we
+        // did updates on some cycles and not others.  By doing an
+        // update on every cycle, we make the brightness reduction
+        // uniform across time, which makes it less perceptible.
+        update();
+        // end the blanking interval
+        endBlank();
+        // if we have pending grayscale data, start sending it
+        if (newGSData)
-            // the chips are now in sync with our data, so we have no more
-            // pending update
-            newGSData = false;
-        }
-        else
-        {
-            // no new grayscale data - just end the blanking cycle without
-            // a new XLAT
-            endBlank(false);
-        }
     void startBlank()
@@ -294,13 +356,16 @@
         blank = 1;        
-    void endBlank(bool needxlat)
+    void endBlank()
-        if (needxlat)
+        // if we've sent new grayscale data since the last blanking
+        // interval, latch it by asserting XLAT
+        if (needXlat)
             // latch the new data while we're still blanked
             xlat = 1;
             xlat = 0;
+            needXlat = false;
         // end the blanking interval and restart the grayscale clock
@@ -350,6 +415,9 @@
         // Start the DMA transfer
+        // we've now cleared the new GS data
+        newGSData = false;
     // Interrupt handler for DMA completion.  The DMA controller calls this
@@ -358,8 +426,15 @@
     // grayscale cycle.    
     void dmaDone()
-        // when the DMA transfer is finished, start the next grayscale cycle
-        endBlank(true);
+        // mark that we need to assert XLAT to latch the new
+        // grayscale data during the next blanking interval
+        needXlat = true;
+        // we're doing the gs update within the blanking cycle, so end
+        // the blanking cycle now that the transfer has completed
+        endBlank();