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

/media/uploads/mjr/pinscape_no_background_small_L7Miwr6.jpg

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 mechanical plunger, button inputs, and feedback device control.

In case you haven't heard of the idea 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 show the backglass artwork. Some cabs also include a third monitor to simulate the DMD (Dot Matrix Display) used for scoring on 1990s machines, or even an original plasma DMD. A computer (usually a Windows PC) 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 trim hardware.

It's possible to buy a pre-built virtual pinball machine, but it also makes a great 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 vpforums.org. Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.

Downloads

  • 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.

Documentation

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 potentiometer (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 mouser.com 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 Aliexpress.com 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 KL25Z can only run one firmware program at a time, so if you install the Pinscape firmware on your KL25Z, it will replace and erase your existing VirtuaPin proprietary firmware. If you do this, the only way to restore your VirtuaPin firmware is to physically ship the KL25Z back to VirtuaPin and ask them to re-flash it. They don't allow you to do this at home, and they don't even allow you to back up your firmware, since they want to protect their proprietary software from copying. For all of these reasons, if you want to run the Pinscape software, I strongly recommend that you buy a "blank" retail KL25Z to use with Pinscape. They only cost about $15 and are available at several online retailers, including Amazon, Mouser, and eBay. The blank retail boards don't come with any proprietary firmware pre-installed, so installing Pinscape won't delete anything that you paid extra for.

With those warnings in mind, if you're absolutely sure that you don't mind permanently erasing your VirtuaPin firmware, it is at least possible to use Pinscape as a replacement for the VirtuaPin firmware. Pinscape uses the same button wiring conventions as the VirtuaPin setup, so you can keep your buttons (although you'll have to update the GPIO pin mappings in the Config Tool to match your physical wiring). As of the June, 2021 firmware, the Vishay VCNL4010 plunger sensor that comes with the VirtuaPin v3 plunger kit is supported, so you can also keep your plunger, if you have that chip. (You should check to be sure that's the sensor chip you have before committing to this route, if keeping the plunger sensor is important to you. The older VirtuaPin plunger kits came with different IR sensors that the Pinscape software doesn't handle.)

Revision:
87:8d35c74403af
Parent:
86:e30a1f60f783
Child:
100:1ff35c07217c
--- a/Plunger/barCodeSensor.h	Fri Apr 21 18:50:37 2017 +0000
+++ b/Plunger/barCodeSensor.h	Tue May 09 05:48:37 2017 +0000
@@ -5,10 +5,19 @@
 // by reading the bar code and decoding it into a position figure.
 //
 // The bar code has to be encoded in a specific format that we recognize.
-// We use a 10-bit reflected Gray code, optically encoded using a Manchester-
-// type of coding.  Each bit is represented as a fixed-width area on the
-// bar, half white and half black.  The bit value is encoded in the order
-// of the colors: Black/White is '0', and White/Black is '1'.
+// We use a reflected Gray code, optically encoded in black/white pixel
+// patterns.  Each bit is represented by a fixed-width area.  Half the
+// pixels in every bit are white, and half are black.  A '0' bit is
+// represented by black pixels in the left half and white pixels in the
+// right half, and a '1' bit is white on the left and black on the right.
+// To read a bit, we identify the set of pixels covering the bit's fixed
+// area in the code, then we see if the left or right half is brighter.
+//
+// (This optical encoding scheme is based on Manchester coding, which is 
+// normally used in the context of serial protocols, but translates to 
+// bar codes straightforwardly.  Replace the serial protocol's time
+// dimension with the spatial dimension across the bar, and replace the
+// high/low wire voltage levels with white/black pixels.)
 //
 // Gray codes are ideal for this type of application.  Gray codes are
 // defined such that each code point differs in exactly one bit from each
@@ -20,21 +29,73 @@
 // the reading will come out as one of points on either side of the true
 // position.  Finally, motion blur will have the same effect, of creating
 // ambiguity in the least significant bits, and thus giving us a reading
-// that's correct to as many bits as we can read with teh blur.
+// that's correct to as many bits as we can make out.
 //
-// We use the Manchester-type optical coding because it has good properties
-// for low-contrast images, and doesn't require uniform lighting.  Each bit's
-// pixel span contains equal numbers of light and dark pixels, so each bit
-// provides its own local level reference.  This means we don't care about
-// lighting uniformity over the whole image, because we don't need a global
-// notion of light and dark, just a local one over a single bit at a time.
+// The half-and-half optical coding also has good properties for our
+// purposes.  The fixed-width bit regions require essentially no CPU work
+// to find the bits, which is good because we're using a fairly slow CPU.
+// The half white/half black coding of each pixel makes every pixel 
+// self-relative in terms of brightness, so we don't need to figure the 
+// black and white thresholds globally for the whole image.  That makes 
+// the physical device engineering and installation easier because the 
+// software can tolerate a fairly wide range of lighting conditions.
 // 
 
 #ifndef _BARCODESENSOR_H_
 #define _BARCODESENSOR_H_
 
 #include "plunger.h"
-#include "tsl14xxSensor.h"
+
+// Gray code to binary mapping for our special coding.  This is a custom
+// 7-bit code, minimum run length 6, 110 positions populated.  The minimum
+// run length is the minimum number of consecutive code points where each
+// bit must remain fixed.  For out optical coding, this defines the smallest
+// "island" size for a black or white bar horizontally.  Small features are
+// prone to light scattering that makes them appear gray on the sensor.
+// Larger features are less subject to scatter, making them easier to 
+// distinguish by brightness level.
+static const uint8_t grayToBin[] = {
+   0,   1,  83,   2,  71, 100,  84,   3,  69, 102,  82, 128,  70, 101,  57,   4,    // 0-15
+  35,  50,  36,  37,  86,  87,  85, 128,  34, 103,  21, 104, 128, 128,  20,   5,    // 16-31
+  11, 128,  24,  25,  98,  99,  97,  40,  68,  67,  81,  80,  55,  54,  56,  41,    // 32-47
+  10,  51,  23,  38, 128,  52, 128,  39,   9,  66,  22, 128,   8,  53,   7,   6,    // 48-63
+  47,  14,  60, 128,  72,  15,  59,  16,  46,  91,  93,  92,  45, 128,  58,  17,    // 64-79
+  48,  49,  61,  62,  73,  88,  74,  75,  33,  90, 106, 105,  32,  89,  19,  18,    // 80-95
+  12,  13,  95,  26, 128,  28,  96,  27, 128, 128,  94,  79,  44,  29,  43,  42,    // 96-111
+ 128,  64, 128,  63, 110, 128, 109,  76, 128,  65, 107,  78,  31,  30, 108,  77     // 112-127
+};
+
+
+// Auto-exposure counter
+class BarCodeExposureCounter
+{
+public:
+    BarCodeExposureCounter()
+    {
+        nDark = 0;
+        nBright = 0;
+        nZero = 0;
+        nSat = 0;
+    }
+    
+    inline void count(int pix)
+    {
+        if (pix <= 2)
+            ++nZero;
+        else if (pix < 12)
+            ++nDark;
+        else if (pix >= 253)
+            ++nSat;
+        else if (pix > 200)
+            ++nBright;
+    }
+    
+    int nDark;      // dark pixels
+    int nBright;    // bright pixels
+    int nZero;      // pixels at zero brightness
+    int nSat;       // pixels at full saturation
+};
+
 
 // Base class for bar-code sensors
 //
@@ -58,13 +119,51 @@
 // full bit, including both "half bits" - it's the full white/black or 
 // black/white pattern area.
 
+struct BarCodeProcessResult
+{
+    int pixofs;
+    int raw;
+    int mask;
+};
+
 template <int nBits, int leftBarWidth, int leftBarMaxOfs, int bitWidth>
-class PlungerSensorBarCode
+class PlungerSensorBarCode: public PlungerSensorImage<BarCodeProcessResult>
 {
 public:
+    PlungerSensorBarCode(PlungerSensorImageInterface &sensor, int npix) 
+        : PlungerSensorImage(sensor, npix, (1 << nBits) - 1)
+    {
+        startOfs = 0;
+    }
+
+    // process a configuration change
+    virtual void onConfigChange(int varno, Config &cfg)
+    {
+        // check for bar-code variables
+        switch (varno)
+        {
+        case 20:
+            // bar code offset
+            startOfs = cfg.plunger.barCode.startPix;
+            break;
+        }
+        
+        // do the generic work
+        PlungerSensorImage::onConfigChange(varno, cfg);
+    }
+
+protected:
     // process the image    
-    bool process(const uint8_t *pix, int npix, int &pos)
+    virtual bool process(const uint8_t *pix, int npix, int &pos, BarCodeProcessResult &res)
     {
+        // adjust auto-exposure
+        adjustExposure(pix, npix);
+        
+        // clear the result descriptor
+        res.pixofs = 0;
+        res.raw = 0;
+        res.mask = 0;
+        
 #if 0 // $$$
 
         // scan from the left edge until we find the fixed '0' start bit
@@ -147,25 +246,46 @@
         }
         else
         {
-            barStart = 4; // $$$ should be configurable via config tool
+            // start at the fixed pixel offset
+            barStart = startOfs;
         }
 
+        // Start with zero in the barcode and success mask.  The mask
+        // indicates which bits we were able to read successfully: a
+        // '1' bit in the mask indicates that the corresponding bit
+        // position in 'barcode' was successfully read, a '0' bit means
+        // that the image was too fuzzy to read.
+        int barcode = 0, mask = 0;
+
         // Scan the bits
-        int barcode = 0;
         for (int bit = 0, x0 = barStart; bit < nBits ; ++bit, x0 += bitWidth)
         {
-            // figure the extent of this bit
-            int x1 = x0 + bitWidth / 2;
-            int x2 = x0 + bitWidth;
+#if 0
+            // Figure the extent of this bit.  The last bit is double
+            // the width of the other bits, to give us a better chance
+            // of making out the small features of the last bit.
+            int w = bitWidth;
+            if (bit == nBits - 1) w *= 2;
+#else
+            // width of the bit
+            const int w = bitWidth;
+#endif
+
+            // figure the bit's internal pixel layout
+            int halfBitWidth = w / 2;
+            int x1 = x0 + halfBitWidth;     // midpoint
+            int x2 = x0 + w;                // right edge
+            
+            // make sure we didn't go out of bounds
             if (x1 > npix) x1 = npix;
             if (x2 > npix) x2 = npix;
 
+#if 0
             // get the average of the pixels over the bit
             int sum = 0;
             for (int x = x0 ; x < x2 ; ++x)
                 sum += pix[x];
-            int avg = sum / bitWidth;
-
+            int avg = sum / w;
             // Scan the left and right sections.  Classify each
             // section according to whether the majority of its
             // pixels are above or below the local average.
@@ -174,20 +294,56 @@
                 lsum += (pix[x] < avg ? 0 : 1);
             for (int x = x1 + 1 ; x < x2 - 1 ; ++x)
                 rsum += (pix[x] < avg ? 0 : 1);
+#else
+            // Sum the pixel readings in each half-bit.  Ignore
+            // the first and last bit of each section, since these
+            // could be contaminated with scattered light from the
+            // adjacent half-bit.  On the right half, hew to the 
+            // right side if the overall pixel width is odd. 
+            int lsum = 0, rsum = 0;
+            for (int x = x0 + 1 ; x < x1 - 1 ; ++x)
+                lsum += pix[x];
+            for (int x = x2 - halfBitWidth + 1 ; x < x2 - 1 ; ++x)
+                rsum += pix[x];
+#endif
                 
-            // if we don't have a winner, fail
-            if (lsum == rsum)
-                return false;
+            // shift a zero bit into the code and success mask
+            barcode <<= 1;
+            mask <<= 1;
 
-            // black/white = 0, white/black = 1
-            barcode = (barcode << 1) | (lsum < rsum ? 0 : 1);
+            // Brightness difference required per pixel.  Higher values
+            // require greater contrast to make a reading, which reduces
+            // spurious readings at the cost of reducing the overall 
+            // success rate.  The right level depends on the quality of
+            // the optical system.  Setting this to zero makes us maximally
+            // tolerant of low-contrast images, allowing for the simplest
+            // optical system.  Our simple optical system suffers from
+            // poor focus, which in turn causes poor contrast in small
+            // features.
+            const int minDelta = 2;
+
+            // see if we could tell the difference in brightness
+            int delta = lsum - rsum;
+            if (delta < 0) delta = -delta;
+            if (delta > minDelta * w/2)
+            {
+                // got it - black/white = 0, white/black = 1
+                if (lsum > rsum) barcode |= 1;
+                mask |= 1;
+            }
         }
 
         // decode the Gray code value to binary
-        pos = grayToBin(barcode);
+        pos = grayToBin[barcode];
         
-        // success
-        return true;
+        // set the results descriptor structure
+        res.pixofs = barStart;
+        res.raw = barcode;
+        res.mask = mask;
+    
+        // return success if we decoded all bits, and the Gray-to-binary
+        // mapping was populated
+        return pos != (1 << nBits) && mask == ((1 << nBits) - 1);
 #endif
     }
     
@@ -255,83 +411,17 @@
         }
     }
 
-    // convert a reflected Gray code value (up to 16 bits) to binary
-    int grayToBin(int grayval)
-    {
-        int temp = grayval ^ (grayval >> 8);
-        temp ^= (temp >> 4);
-        temp ^= (temp >> 2);
-        temp ^= (temp >> 1);
-        return temp;
-    }
-};
-
-// Auto-exposure counter
-class BarCodeExposureCounter
-{
-public:
-    BarCodeExposureCounter()
-    {
-        nDark = 0;
-        nBright = 0;
-        nZero = 0;
-        nSat = 0;
-    }
-    
-    inline void count(int pix)
-    {
-        if (pix <= 2)
-            ++nZero;
-        else if (pix < 12)
-            ++nDark;
-        else if (pix >= 253)
-            ++nSat;
-        else if (pix > 200)
-            ++nBright;
-    }
-    
-    int nDark;      // dark pixels
-    int nBright;    // bright pixels
-    int nZero;      // pixels at zero brightness
-    int nSat;       // pixels at full saturation
-};
-
-// PlungerSensor interface implementation for bar code readers.
-//
-// Bar code readers are image sensors, so we have a pixel size for
-// the sensor.  However, this isn't the scale for the readings.  The
-// scale for the readings is determined by the number of bits in the
-// bar code, since an n-bit bar code can encode 2^n distinct positions.
-//
-template <int nBits, int leftBarWidth, int leftBarMaxOfs, int bitWidth>
-class PlungerSensorBarCodeTSL14xx: public PlungerSensorTSL14xxSmall,
-    PlungerSensorBarCode<nBits, leftBarWidth, leftBarMaxOfs, bitWidth>
-{
-public:
-    PlungerSensorBarCodeTSL14xx(int nativePix, PinName si, PinName clock, PinName ao)
-        : PlungerSensorTSL14xxSmall(nativePix, (1 << nBits) - 1, si, clock, ao)
-    {
-        // the native scale is the number of positions we can
-        // encode in the bar code
-        nativeScale = 1023;
-    }
-    
-protected:
-    
-    // process the image through the bar code reader
-    virtual bool process(const uint8_t *pix, int npix, int &pos)
-    {
-        // adjust the exposure
-        adjustExposure(pix, npix);
-        
-        // do the standard bar code processing
-        return PlungerSensorBarCode<nBits, leftBarWidth, leftBarMaxOfs, bitWidth>
-            ::process(pix, npix, pos);
-    }
-    
     // bar code sensor orientation is fixed
     virtual int getOrientation() const { return 1; }
     
+    // send extra status report headers
+    virtual void extraStatusHeaders(USBJoystick &js, BarCodeProcessResult &res)
+    {
+        // Send the bar code status report.  We use coding type 1 (Gray code,
+        // Manchester pixel coding).
+        js.sendPlungerStatusBarcode(nBits, 1, res.pixofs, bitWidth, res.raw, res.mask);
+    }
+    
     // adjust the exposure
     void adjustExposure(const uint8_t *pix, int npix)
     {
@@ -342,23 +432,24 @@
         // pixels has to look: the bit area will be 50% black and 50%
         // white, and the margins will be all white.  For maximum
         // contrast, target an exposure level where the black pixels
-        // are all below the middle brightness level and the white
+        // are all below a certain brightness level and the white
         // pixels are all above.  Start by figuring the number of
         // pixels above and below.
-        int nDark = 0;
+        const int medianTarget = 160;
+        int nBelow = 0;
         for (int i = 0 ; i < npix ; ++i)
         {
-            if (pix[i] < 200)
-                ++nDark;
+            if (pix[i] < medianTarget)
+                ++nBelow;
         }
         
-        // Figure the percentage of black pixels: the left bar is
+        // Figure the desired number of black pixels: the left bar is
         // all black pixels, and 50% of each bit is black pixels.
-        int targetDark = leftBarWidth + (nBits * bitWidth)/2;
+        int targetBelow = leftBarWidth + (nBits * bitWidth)/2;
         
         // Increase exposure time if too many pixels are below the
         // halfway point; decrease it if too many pixels are above.
-        int d = nDark - targetDark;
+        int d = nBelow - targetBelow;
         if (d > 5 || d < -5)
         {
             axcTime += d;
@@ -475,20 +566,21 @@
         if (axcTime > 2500)
             axcTime = 2500;
     }
-};
 
-// TSL1401CL - 128-bit image sensor, used as a bar code reader
-class PlungerSensorTSL1401CL: public PlungerSensorBarCodeTSL14xx<
-    10,  // number of bits in code
-    0,   // left delimiter bar width in pixels (0 for none)
-    24,  // maximum left margin width in pixels
-    12>  // pixel width of each bit
-{
-public:
-    PlungerSensorTSL1401CL(PinName si, PinName clock, PinName a0)
-        : PlungerSensorBarCodeTSL14xx(128, si, clock, a0)
+#if 0
+    // convert a reflected Gray code value (up to 16 bits) to binary
+    static inline int grayToBin(int grayval)
     {
+        int temp = grayval ^ (grayval >> 8);
+        temp ^= (temp >> 4);
+        temp ^= (temp >> 2);
+        temp ^= (temp >> 1);
+        return temp;
     }
+#endif
+
+    // bar code starting pixel offset
+    int startOfs;
 };
 
 #endif