13. I/O Controllers
One of the big things that elevates the virtual cabinet experience
above ordinary desktop computer pinball is the ability to use real
pinball controls: flipper buttons, coin slots, a plunger, "nudging" by
actually nudging the cabinet. An equally big enhancement is feedback
devices that create tactile effects, lighting effects, and mechanical
sound effects that aren't just coming from a speaker.
If you're new to virtual pinball, you might wonder how all of this is
possible, since normal PCs don't have any provisions for connecting
any of these unusual devices. There's no "flipper button" connector
on a Dell desktop. The secret ingredient is something called an I/O
Controller ("I/O" for "Input/Output"). These are special hardware
devices that plug in to the standard PC ports (usually USB) and
provide the special wiring needed to connect buttons, accelerometers,
plunger sensors, solenoids, lights, and so on. They provide the
physical bridge between the PC and the unique pinball hardware.
This chapter gets into the details of what these devices do, and
offers some suggestions for what to buy. The subject can seem
overwhelming at first, because there are lots of product options, and
they all have different combinations of features and functions. We'll
try to make it easier by breaking things down by function, and giving
you a comprehensive list of the products available and which functions
they offer. Towards the end of the chapter, you'll find a
product/feature matrix that shows everything at a glance.
I/O controller functions
Let's start by looking at the main categories of functions that these
devices can handle.
Button input: A device that lets you wire regular pinball
buttons to the PC is called a "key encoder". These devices are pretty
easy to set up. You just run a pair of wires to each button (flipper,
Start, etc) and connect them to the encoder. The encoder attaches to
the PC with a USB cable. When you press a connected button, the
encoder emulates either a keyboard key press or a joystick button
press. As far as the PC software is concerned, you're just typing
on the keyboard or using a joystick.
Nudge input: This type of device uses an electronic
accelerometer to sense the motion of the cabinet. Good accelerometers
are sensitive enough and accurate enough to detect when you nudge the
cabinet and to measure how hard each nudge is. The pinball software
can use this information to apply a corresponding acceleration to the
virtual ball - in proportion to the strength of the nudge, so you can
get realistic reactions for soft nudges, hard nudges, and a continuum
in between. Nudge devices usually connect to the PC via a USB cable
and emulate joysticks, so a physical nudge looks to the PC software
like a momentary deflection on a joystick handle. The strength of the
nudge is indicated by the magnitude of the deflection, which is what
allows the software to differentiate between soft nudges and hard
Plunger input: This is a very specialized type of input device,
because it has to use some type of position sensor to track the motion
of the plunger, and then translate the readings from that sensor into
a format that the PC can understand. Plunger devices usually attach
to the PC via a USB cable and emulate joystick input. This is the
same way most nudge sensors work, so we need a way for the PC to tell
the two apart. This is usually accomplished by using different
"joystick axis" assignments for each device.
Feedback output: Output controllers let you connect
feedback devices to the PC so that the software can control them. As
with the other devices, these usually use USB connections to the PC.
Unlike the various input controllers, which all emulate ordinary PC
input devices (mainly keyboards and joysticks), output controllers all
need special software on the PC. Fortunately, the required special
software is already integrated with the main pinball player programs.
Now let's look at the available devices. Some of the devices fall
neatly into single categories, and others can perform multiple functions.
Pinscape Controller, running on just the KL25Z (no expansion boards).
Open source software, DIY hardware; about $15 for the main microcontroller board.
Key encoder, plunger input, nudge input, feedback device control.
This is an open source project that can handle all of the I/O
controller functions with a single device. The main hardware required
is a KL25Z, which is a $15 microcontroller that comes fully assembled
and ready to use. By itself, the KL25Z can handle button input and
nudging (it has an excellent built-in accelerometer). Plunger input
and feedback device control require additional hardware that's
described later in this Build Guide. The Pinscape software does just
about everything the various single-function commercial devices do,
with some added bells and whistles of its own. It includes fully
assignable button inputs (using keyboard keys and/or joystick
buttons), a "shift button" feature, LedWiz emulation for universal
software compatibility, "night mode", high-precision nudge input,
high-precision plunger input, and numerous other features. It's
highly configurable via its setup program (which runs on Windows,
and is free and open-source), and the firmware itself is
open-source, so you're free to customize it if you need to do
anything beyond what the configuration options allow, or if
you want to add whole new features. The firmware includes
built-in support for several types of plunger sensor technologies,
so you have a choice of different plunger setups.
The standalone KL25Z can handle button, nudge, and plunger input
with little more work than attaching wires. It gets a little more
complicated if you want to use it with feedback devices, because
it needs some additional electronics to do that, as explained
in Pinscape Outputs Setup (Standalone KL25Z).
Pinscape Controller with expansion boards. Open source
software and hardware design; components cost about $100 for
a full build. Key encoder, plunger input, nudge input, feedback
This is an extension of the basic Pinscape Controller project that
adds a set of circuit boards, primarily to provide more
feedback device outputs. The boards make it possible to
control a much larger number of feedback devices than the KL25Z can
control on its own. The boards also provide built-in handling for
high-power devices, so that you can connect things like motors,
solenoids, replay knockers, fans, and flashers without any
additional booster circuits. The hardware design is open-source,
so you can build everything yourself from components, which add up to
about $100 for a full-featured build. You can also opt to build only
sections of the boards if you only need a subset of the features,
which reduces the cost accordingly.
Zeb's Boards plunger kit.
Commercial, about $140 from
input, nudge sensor, key encoder.
This kit comes with the control board and plunger sensor that attaches
to a standard pinball plunger (available separately for about $30).
In addition to plunger input, Zeb's kit also handles nudging via an
on-board accelerometer, and provides key encoding for up to 20 buttons
(with fixed key mappings). Zeb's plunger gets the best user
reviews of the commercial plunger options. It uses a high-precision
sensor for the plunger that provides realistic plunger motion in
the pinball simulation.
VirtuaPin plunger kit.
Commercial, $140 to $160 from
. Plunger input,
nudge sensor, key encoder.
The VirtuaPin kit comes with a control board and plunger sensor, and
optionally includes the physical plunger assembly. Like other
commercial plunger kits, the VP kit is very easy to set up, with
little assembly required beyond attaching the sensor to the plunger.
The control board has an excellent on-board accelerometer for nudge
sensing, and has wiring for up to 16 button inputs. Button inputs are
hard-coded as joystick buttons and can't be assigned to keyboard keys.
If you're picky about realism in the plunger, be aware that this kit
uses an IR proximity sensor to detect plunger position, and these
sensors have relatively poor distance resolution. Some users have
reported that the plunger animation can be choppy.
i-Pac 2 and i-Pac 4.
Commercial, $39/$59 from
. Key encoder.
The i-Pac devices are full-featured key encoders. Their target market
is video game cabinet builders, but they work equally well for virtual
pinball, since the needs are basically the same. Buttons are fully
assignable (via a setup program on the PC) to keyboard keys and
joystick buttons. The devices have a "shift button" feature that lets
you assign two meanings to each physical button by holding down a
designated shift button to activate the second meaning.
i-Pac Ultimate I/O.
Commercial, $99 from
. Key encoder,
feedback device control.
This is a hybrid of the i-Pac and PacLED devices that provides button
input encoding and feedback device control. The key encoder features
are just like the i-Pac devices, with 48 button inputs. The feedback
output controller is designed specifically for attaching 32 small
(20mA) RGB LEDs. For a virtual pinball cabinet, you'll want to attach
other devices that require higher power, so you'll need external
booster circuitry, such as Zeb's booster board. One warning: as of
this writing, this device's output controller feature isn't as well
supported in the standard virtual pinball software as the LedWiz and
PacLed devices, so you might encounter some difficulty setting up the
software to take advantage of it. The button input feature will work
The LedWiz was the first output controller widely adopted among
virtual pinball cabinet builders, and as a result, it's the most
universally supported option. This device is aimed at video game
cabinet builders, so it was designed especially for controlling LEDs
(thus the name), but it's not limited to LEDs. It can control just
about any type of device. The caveat is that it has a low limit
on how much current it can control per device (500mA), so you can't
connect high-power devices directly. You can work around that by
adding an external booster board to increase its power limits.
That 500mA limit is adequate for most types of lights, including
flasher LEDs and button lamps. A booster is needed for most
mechanical devices, like knockers, motors, and solenoids.
Commercial, $59 from
This device is well supported by the newer open-source pinball
software systems (including Visual Pinball and PinballX), but it's not
as compatible with older systems like Future Pinball as the LedWiz is.
It provides 64 outputs for small LEDs. Like the LedWiz, this device
was designed for video game cabinet builders, but its power handling
is even more limited and isn't sufficient for high-powered lights like
flashers and strobes. So you'll need to combine this with a booster
board for almost anything in a virtual pinball cabinet.
SainSmart USB relay boards. Commercial, about $20-$40. Feedback
SainSmart makes USB-controlled relay board with 8 relay outputs.
Software on the PC can send USB commands to turn attached devices on
and off through relay switches. The relays can be used to control
devices that use high power levels, so they're good for devices
like solenoids, contactors, and replay knockers. However, these
boards aren't a good choice for lighting devices, since relays
on simple on/off switches and thus can't control brightness. For
lights (especially flashers and button lights), you'll want to be
able to control the intensity level of each output. The other
slight disadvantage of relays is that they add a small lag time
for switching devices on and off, which can make the device response
slightly out of sync with the game action. Most people don't find
this noticeable, though.
Warning! DOF is currently only compatible with the 8-relay Sainsmart
boards. Sainsmart makes the boards in different sizes, from 4 to 16
channels, but DOF only works with the 8-relay version.
Warning! There seem to be some no-brand devices out there that
look ridiculously similar to the Sainsmarts, with the same blue
lays laid out the same way, but which aren't compatible at the software level.
That means they won't work with the existing pinball software,
unless you can do some additional programming to add support
yourself. I'd avoid look-alike boards that aren't clearly branded
as Sainsmart products.
Zeb's Boards booster board.
Commercial, $75 from
This board lets boost the power from 16 outputs on an LedWiz or PacLed
output controller. The booster board itself isn't an output
controller, so you can't use it alone; it has to be used in
conjunction with one of the output controllers. The booster board
raises the power level on 16 of the output controller's ports to 6A,
which is enough to control anything in a pin cab, including high-power
devices like replay knockers, shaker motors, gear motors, fans,
beacons, and solenoids. If you need more than 16 boosted ports, you
can add more of these boards to boost an additional 16 ports per
SainSmart (non-USB) relay board. Commercial, $20 to $40.
Feedback device add-on.
These boards are similar to the SainSmart USB relay boards, but they're not
controlled by USB. Instead, they're controlled by individual inputs
to the relays. You can connect the relay control inputs to the
output ports of an LedWiz or PacLed unit to boost the power
handling capability of the controller via the relays. You can
then attach a high-power device, such as a replay knocker or
solenoid, to the relay. The controller unit will switch the relay on
and off, and the relay will in turn switch your high-power device
on and off. This is a simple way to boost the power handling of
an LedWiz or PacLed unit. Note that the relay switching adds a
small amount of lag time, which can make the feedback response
slightly out of sync with the game action, although most people
who have set these up don't find this to be noticeable.
Zeb's Boards output kits.
Commercial, $550 to $900 from
system including controller and
These kits offer turnkey feedback setups that include not only the
output controller device but also all of the feedback devices
themselves, all fully assembled and wired. Everything comes
pre-mounted to a couple of modular panels for easy installation in a
For the DIYer: I'm biased, obviously, but if you like building
things yourself, my pick would be Pinscape. For a fully decked-out
system with all the feedback devices, go with the expansion boards.
For the input features only (buttons, plunger, nudging), the
standalone KL25Z is all you need. I'm pretty sure Pinscape has all of
the features of the best-of-breed commercial products
(plus some extra features they don't have), equal or better
performance, and a lower price tag. And the open-source design
puts you in complete control. You can change anything that's not
to your exact liking; and if you take "DIY" especially seriously,
you can use my code as a starting point and rewrite as much of
it as you want from scratch.
If you want "no compromises": Again, I'm biased, but I think
the answer here is Pinscape. It has the most full-featured and
highest performance implementation I'm aware of for each of the
components. It's highly configurable through its Config Tool, so you
can set it up exactly how you want it. And again, it's open-source,
so if there is anything you want it to do that it doesn't already do,
you can add it; or if there's anything it does do that's not quite the
way you want it, you can change it.
If you're uncomfortable with DIY: You'll probably be happier
with the commercial options if you're not comfortable building this
sort of thing yourself. The commercial products come ready to
install, with only some basic setup required. The big challenge is
figuring out which devices you need, since their functions overlap in
somewhat confusing ways. Here are my recommendations for some common
For a simple feedback system with lights only: If the only
feedback devices you want are lighting devices (flashers, strobes, and
button lights, for example), I'd recommend an LedWiz as the output
controller. The LedWiz is inexpensive, and for just lights, it's
simple to set up, since that's exactly what it's designed for. A
single LedWiz has plenty of ports for a pin cab's lighting needs. The
LedWiz is a good choice for lighting devices because it can display a
range of brightness levels, which allows for fades, flash patterns,
and RGB color mixing effects. The LedWiz isn't as ideal for
high-power devices like solenoids and motors, since it can only handle
limited power to each port; while it's possible to use it for these
devices, you need additional hardware add-ons, which largely negates
the whole "it's simple" advantage.
For a simple feedback system with solenoids and motors only: If
you want a feedback system consisting only of tactile effects (replay
knocker, flipper and bumper solenoids, shaker motor), get a SainSmart
USB relay board. I'd get the 16-output type so that you have plenty
of outputs for extras you might want to add later. The SainSmart
board is the easiest thing to set up for high-power devices. The
downside is that relays are strictly On/Off switches, so the SainSmart
can't display different brightness levels if you use it to control
lights - it can only turn them fully on and fully off. That makes it
good for devices like solenoids and motors, but not so good for lamps
and LEDs, where you need brightness control to get the full range of
effects. The other disadvantage is that the relays are mechanical, so
they can eventually wear out; some people on the forums have reported
having to replace their SainSmart boards every couple of years due
to relay failure.
For a plunger-less system: If you don't want to include a
plunger in your setup, use a KL25Z running Pinscape as the input
device. You don't need the expansion boards if you're just using the
input features. The installation work for buttons and nudge input is
pretty much the same as for any of the commercial options, and
Pinscape is a lot cheaper and has more features.
For a turn-key plunger: If you want a plunger but don't want to
build the electronics yourself, buy Zeb's plunger kit. It's easy to
set up and gets generally good reviews from users.
For a turn-key feedback system: If you're the opposite of a
DIYer, and you don't want to do a lot of planning or parts sourcing or
assembly work, buy one of Zeb's pre-built feedback kits. They're
expensive, but they'll save you a lot of work, and they'll eliminate
any anxiety you might feel about the things going wrong if you build
Here's a summary of the key features of the available controllers,
to help you decide on a combination of devices for your system based
on the features you plan to include.
|Pinscape w/expansion boards
|Zeb's Boards plunger kit
|VirtuaPin plunger kit
|i-Pac Ultimate I/O
|SainSmart USB relay board
|Zeb's Boards booster board
|SainSmart relay board (non-USB)
|Zeb's Boards output kits
The 4 Amp limit applies to the
general purpose outputs on the power board. There are 32 of these on
each power board. In addition, the main board has 16 flasher/strobe
outputs that can handle 1.5A each, and 16 outputs for button LEDs that
can handle 20-50mA each. The typical setup uses one main board and
one power board, which gives you 65 total outputs, plenty for a
decked-out cab. If you need more, you can add extra power boards for
another 32 of the high-power outputs per, up to the software limit of
128 total outputs.
This device's outputs are
designed to drive low-power LEDs, which it can do without any extra
booster circuitry. A booster board is needed to drive anything
needing higher power, such as flasher LEDs or mechanical feedback
The LedWiz can handle 500mA per
output, which is sufficient for most types of lights, including LED
flashers and button lamps. A booster board is required for most
non-lighting devices, such as contactors, replay knockers, solenoids,
fans, shakers, and gear motors.
This device works in conjunction
with one of the output controllers (LedWiz, PacLed-64, etc). It
can't be used alone; it has to be used in combination with an output