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.)

Committer:
mjr
Date:
Wed Dec 22 21:48:24 2021 +0000
Revision:
116:80ebb41bad94
Parent:
113:7330439f2ffc
Add Arnoz RigMaster and KLShield boards

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 111:42dc75fbe623 1 // VCNL4010 IR proximity sensor
mjr 111:42dc75fbe623 2
mjr 111:42dc75fbe623 3 #include "mbed.h"
mjr 111:42dc75fbe623 4 #include "math.h"
mjr 111:42dc75fbe623 5 #include "VCNL4010.h"
mjr 111:42dc75fbe623 6
mjr 113:7330439f2ffc 7
mjr 113:7330439f2ffc 8 VCNL4010::VCNL4010(PinName sda, PinName scl, bool internalPullups, int iredCurrent)
mjr 111:42dc75fbe623 9 : i2c(sda, scl, internalPullups)
mjr 111:42dc75fbe623 10 {
mjr 113:7330439f2ffc 11 // Calculate the scaling factor with a minimum proximitiy count of 5.
mjr 113:7330439f2ffc 12 // In actual practice, the minimum will usually be a lot higher, but
mjr 113:7330439f2ffc 13 // this is a safe default that gives us valid distance calculations
mjr 113:7330439f2ffc 14 // across almost the whole possible range of count values. (Why not
mjr 113:7330439f2ffc 15 // zero? Because of the inverse relationship between distance and
mjr 113:7330439f2ffc 16 // brightness == proximity count. 1/0 isn't meaningful, so we have
mjr 113:7330439f2ffc 17 // to use a non-zero minimum in the scaling calculation. 5 is so
mjr 113:7330439f2ffc 18 // low that it'll probably never actually happen in real readings,
mjr 113:7330439f2ffc 19 // but still gives us a reasonable scaled range.)
mjr 113:7330439f2ffc 20 calibrating = false;
mjr 113:7330439f2ffc 21 minProxCount = 100;
mjr 113:7330439f2ffc 22 maxProxCount = 65535;
mjr 113:7330439f2ffc 23 parkProxCount = 20000;
mjr 113:7330439f2ffc 24 dcOffset = 0;
mjr 113:7330439f2ffc 25 lastProxCount = 0;
mjr 113:7330439f2ffc 26 calcScalingFactor();
mjr 113:7330439f2ffc 27
mjr 113:7330439f2ffc 28 // remember the desired IRED current setting
mjr 113:7330439f2ffc 29 this->iredCurrent = iredCurrent;
mjr 111:42dc75fbe623 30 }
mjr 111:42dc75fbe623 31
mjr 113:7330439f2ffc 32 // Initialize the sensor device
mjr 111:42dc75fbe623 33 void VCNL4010::init()
mjr 111:42dc75fbe623 34 {
mjr 113:7330439f2ffc 35 // debugging instrumentation
mjr 111:42dc75fbe623 36 printf("VCNL4010 initializing\r\n");
mjr 111:42dc75fbe623 37
mjr 111:42dc75fbe623 38 // reset the I2C bus
mjr 111:42dc75fbe623 39 i2c.reset();
mjr 111:42dc75fbe623 40
mjr 111:42dc75fbe623 41 // Set the proximity sampling rate to the fastest available rate of
mjr 113:7330439f2ffc 42 // 250 samples/second (4ms/sample). This isn't quite fast enough for
mjr 113:7330439f2ffc 43 // perfect plunger motion tracking - a minimum sampling frequency of
mjr 113:7330439f2ffc 44 // 400/s is needed to avoid aliasing during the bounce-back phase of
mjr 113:7330439f2ffc 45 // release motions. But the plunger-independent part of the code
mjr 113:7330439f2ffc 46 // does some data processing to tolerate aliasing for even slower
mjr 113:7330439f2ffc 47 // sensors than this one, so this isn't a showstopper. Apart from
mjr 113:7330439f2ffc 48 // the potential for aliasing during fast motion, 250/s is plenty
mjr 113:7330439f2ffc 49 // fast enough for responsive input and smooth animation.
mjr 111:42dc75fbe623 50 writeReg(0x82, 0x07);
mjr 111:42dc75fbe623 51
mjr 111:42dc75fbe623 52 // Set the current for the IR LED (the light source for proximity
mjr 113:7330439f2ffc 53 // measurements). This is in units of 10mA, up to 200mA. If the
mjr 113:7330439f2ffc 54 // parameter is zero in the configuration, apply a default. Make
mjr 113:7330439f2ffc 55 // sure it's in range (1..20).
mjr 111:42dc75fbe623 56 //
mjr 113:7330439f2ffc 57 // Note that the nominal current level isn't the same as the actual
mjr 113:7330439f2ffc 58 // current load on the sensor's power supply. The nominal current
mjr 113:7330439f2ffc 59 // set here is the instantaneous current the chip uses to generate
mjr 113:7330439f2ffc 60 // IR pulses. The pulses have a low duty cycle, so the continuous
mjr 113:7330439f2ffc 61 // current drawn on the chip's power inputs is much lower. The
mjr 113:7330439f2ffc 62 // data sheet says that the total continuous power supply current
mjr 113:7330439f2ffc 63 // drawn with the most power-hungry settings (IRED maxed out at
mjr 113:7330439f2ffc 64 // 200mA, sampling frequency maxed at 250 Hz) is only 4mA. So
mjr 113:7330439f2ffc 65 // there's no need to worry about blowing a fuse on the USB port
mjr 113:7330439f2ffc 66 // or frying the KL25Z 3.3V regulator - the chip draws negligible
mjr 113:7330439f2ffc 67 // power in those terms, even at the maximum IRED setting.
mjr 113:7330439f2ffc 68 uint8_t cur = static_cast<uint8_t>(iredCurrent);
mjr 113:7330439f2ffc 69 cur = (cur == 0 ? 10 : cur < 1 ? 1 : cur > 20 ? 20 : cur);
mjr 113:7330439f2ffc 70 writeReg(0x83, cur);
mjr 111:42dc75fbe623 71
mjr 111:42dc75fbe623 72 // disable self-timed measurements - we'll start measurements on demand
mjr 111:42dc75fbe623 73 writeReg(0x80, 0x00);
mjr 111:42dc75fbe623 74
mjr 111:42dc75fbe623 75 // start the sample timer, which we use to gather timing statistics
mjr 111:42dc75fbe623 76 sampleTimer.start();
mjr 111:42dc75fbe623 77
mjr 113:7330439f2ffc 78 // debugging instrumentation
mjr 111:42dc75fbe623 79 printf("VCNL4010 initialization done\r\n");
mjr 111:42dc75fbe623 80 }
mjr 111:42dc75fbe623 81
mjr 113:7330439f2ffc 82 // Start a proximity measurement. This initiates a proximity reading
mjr 113:7330439f2ffc 83 // in the chip, and returns immediately, allowing the KL25Z to tend to
mjr 113:7330439f2ffc 84 // other tasks while waiting for the reading to complete. proxReady()
mjr 113:7330439f2ffc 85 // can be used to poll for completion.
mjr 111:42dc75fbe623 86 void VCNL4010::startProxReading()
mjr 111:42dc75fbe623 87 {
mjr 111:42dc75fbe623 88 // set the prox_od (initiate proximity on demand) bit (0x08) in
mjr 111:42dc75fbe623 89 // the command register, if it's not already set
mjr 111:42dc75fbe623 90 uint8_t b = readReg(0x80);
mjr 111:42dc75fbe623 91 if ((b & 0x08) == 0)
mjr 111:42dc75fbe623 92 {
mjr 111:42dc75fbe623 93 tSampleStart = sampleTimer.read_us();
mjr 111:42dc75fbe623 94 writeReg(0x80, b | 0x08);
mjr 111:42dc75fbe623 95 }
mjr 111:42dc75fbe623 96 }
mjr 111:42dc75fbe623 97
mjr 113:7330439f2ffc 98 // Check if a proximity sample is ready. Implicitly starts a new reading
mjr 113:7330439f2ffc 99 // if one isn't already either completed or in progress. Returns true if
mjr 113:7330439f2ffc 100 // a reading is ready, false if not.
mjr 111:42dc75fbe623 101 bool VCNL4010::proxReady()
mjr 111:42dc75fbe623 102 {
mjr 111:42dc75fbe623 103 // read the command register to get the status bits
mjr 111:42dc75fbe623 104 uint8_t b = readReg(0x80);
mjr 111:42dc75fbe623 105
mjr 111:42dc75fbe623 106 // if the prox_data_rdy bit (0x20) is set, a reading is ready
mjr 111:42dc75fbe623 107 if ((b & 0x20) != 0)
mjr 111:42dc75fbe623 108 return true;
mjr 111:42dc75fbe623 109
mjr 111:42dc75fbe623 110 // Not ready. Since the caller is polling, they must expect a reading
mjr 111:42dc75fbe623 111 // to be in progress; if not, start one now. A reading in progress is
mjr 111:42dc75fbe623 112 // indicated and initiated by the prox_od bit
mjr 111:42dc75fbe623 113 if ((b & 0x08) == 0)
mjr 111:42dc75fbe623 114 {
mjr 111:42dc75fbe623 115 tSampleStart = sampleTimer.read_us();
mjr 111:42dc75fbe623 116 writeReg(0x80, b | 0x08);
mjr 111:42dc75fbe623 117 }
mjr 111:42dc75fbe623 118
mjr 111:42dc75fbe623 119 // a reading is available if the prox_data_rdy (0x08) is set
mjr 111:42dc75fbe623 120 return (b & 0x20) != 0;
mjr 111:42dc75fbe623 121 }
mjr 111:42dc75fbe623 122
mjr 113:7330439f2ffc 123 // Read the current proximity reading. If a reading isn't ready,
mjr 113:7330439f2ffc 124 // we'll block until one is, up to the specified timeout interval.
mjr 113:7330439f2ffc 125 // Returns zero if a reading was successfully retrieved, or a
mjr 113:7330439f2ffc 126 // non-zero error code if a timeout or error occurs.
mjr 113:7330439f2ffc 127 //
mjr 113:7330439f2ffc 128 // Note that the returned proximity count value is the raw reading
mjr 113:7330439f2ffc 129 // from the sensor, which indicates the intensity of the reflected
mjr 113:7330439f2ffc 130 // light detected on the sensor, on an abstract scale from 0 to
mjr 113:7330439f2ffc 131 // 65535. The proximity count is inversely related to the distance
mjr 113:7330439f2ffc 132 // to the target, but the relationship also depends upon many other
mjr 113:7330439f2ffc 133 // factors, such as the size and reflectivity of the target, ambient
mjr 113:7330439f2ffc 134 // light, and internal reflections within the sensor itself and
mjr 113:7330439f2ffc 135 // within the overall apparatus.
mjr 113:7330439f2ffc 136 int VCNL4010::getProx(int &proxCount,
mjr 113:7330439f2ffc 137 uint32_t &tMid, uint32_t &dt, uint32_t timeout_us)
mjr 111:42dc75fbe623 138 {
mjr 113:7330439f2ffc 139 // If the chip isn't responding, try resetting it. I2C will
mjr 113:7330439f2ffc 140 // generally report 0xFF on all byte reads when a device isn't
mjr 113:7330439f2ffc 141 // responding to commands, since the pull-up resistors on SDA
mjr 113:7330439f2ffc 142 // will make all data bits look like '1' on read. It's
mjr 113:7330439f2ffc 143 // conceivable that a device could lock up while holding SDA
mjr 113:7330439f2ffc 144 // low, too, so a value of 0x00 could also be reported. So to
mjr 113:7330439f2ffc 145 // sense if the device is answering, we should try reading a
mjr 113:7330439f2ffc 146 // register that, when things are working properly, should
mjr 113:7330439f2ffc 147 // always hold a value that's not either 0x00 or 0xFF. For
mjr 113:7330439f2ffc 148 // the VCNL4010, we can read the product ID register, which
mjr 113:7330439f2ffc 149 // should report ID value 0x21 per the data sheet. The low
mjr 113:7330439f2ffc 150 // nybble is a product revision number, so we shouldn't
mjr 113:7330439f2ffc 151 // insist on the value 0x21 - it could be 0x22 or 0x23, etc,
mjr 113:7330439f2ffc 152 // in future revisions of this chip. But in any case, the
mjr 113:7330439f2ffc 153 // register should definitely not be 0x00 or 0xFF, so it's
mjr 113:7330439f2ffc 154 // a good solid test.
mjr 113:7330439f2ffc 155 uint8_t prodId = readReg(0x81);
mjr 113:7330439f2ffc 156 if (prodId == 0x00 || prodId == 0xFF)
mjr 113:7330439f2ffc 157 {
mjr 113:7330439f2ffc 158 // try resetting the chip
mjr 113:7330439f2ffc 159 init();
mjr 113:7330439f2ffc 160
mjr 113:7330439f2ffc 161 // check if that cleared the problem; if not, give up and
mjr 113:7330439f2ffc 162 // return an error
mjr 113:7330439f2ffc 163 prodId = readReg(0x81);
mjr 113:7330439f2ffc 164 if (prodId == 0x00 || prodId == 0xFF)
mjr 113:7330439f2ffc 165 return 1;
mjr 113:7330439f2ffc 166 }
mjr 113:7330439f2ffc 167
mjr 111:42dc75fbe623 168 // wait for the sample
mjr 111:42dc75fbe623 169 Timer t;
mjr 111:42dc75fbe623 170 t.start();
mjr 111:42dc75fbe623 171 for (;;)
mjr 111:42dc75fbe623 172 {
mjr 111:42dc75fbe623 173 // check for a sample
mjr 111:42dc75fbe623 174 if (proxReady())
mjr 111:42dc75fbe623 175 break;
mjr 111:42dc75fbe623 176
mjr 111:42dc75fbe623 177 // if we've exceeded the timeout, return failure
mjr 111:42dc75fbe623 178 if (t.read_us() > timeout_us)
mjr 111:42dc75fbe623 179 return -1;
mjr 111:42dc75fbe623 180 }
mjr 111:42dc75fbe623 181
mjr 111:42dc75fbe623 182 // figure the time since we initiated the reading
mjr 111:42dc75fbe623 183 dt = sampleTimer.read_us() - tSampleStart;
mjr 111:42dc75fbe623 184
mjr 111:42dc75fbe623 185 // figure the midpoint time
mjr 111:42dc75fbe623 186 tMid = tSampleStart + dt/2;
mjr 111:42dc75fbe623 187
mjr 111:42dc75fbe623 188 // read the result from the sensor, as a 16-bit proximity count value
mjr 113:7330439f2ffc 189 int N = (static_cast<int>(readReg(0x87)) << 8) | readReg(0x88);
mjr 113:7330439f2ffc 190
mjr 113:7330439f2ffc 191 // remember the last raw reading
mjr 113:7330439f2ffc 192 lastProxCount = N;
mjr 111:42dc75fbe623 193
mjr 111:42dc75fbe623 194 // start a new reading, so that the sensor is collecting the next
mjr 111:42dc75fbe623 195 // reading concurrently with the time-consuming floating-point math
mjr 111:42dc75fbe623 196 // we're about to do
mjr 111:42dc75fbe623 197 startProxReading();
mjr 113:7330439f2ffc 198
mjr 113:7330439f2ffc 199 // if calibration is in progress, note the new min/max proximity
mjr 113:7330439f2ffc 200 // count readings, if applicable
mjr 113:7330439f2ffc 201 if (calibrating)
mjr 113:7330439f2ffc 202 {
mjr 113:7330439f2ffc 203 if (N < minProxCount)
mjr 113:7330439f2ffc 204 minProxCount = N;
mjr 113:7330439f2ffc 205 if (N > maxProxCount)
mjr 113:7330439f2ffc 206 maxProxCount = N;
mjr 113:7330439f2ffc 207 }
mjr 113:7330439f2ffc 208
mjr 113:7330439f2ffc 209 // report the raw count back to the caller
mjr 113:7330439f2ffc 210 proxCount = N;
mjr 113:7330439f2ffc 211
mjr 111:42dc75fbe623 212 // success
mjr 111:42dc75fbe623 213 return 0;
mjr 111:42dc75fbe623 214 }
mjr 111:42dc75fbe623 215
mjr 113:7330439f2ffc 216 // Restore the saved calibration data from the configuration
mjr 113:7330439f2ffc 217 void VCNL4010::restoreCalibration(Config &config)
mjr 113:7330439f2ffc 218 {
mjr 113:7330439f2ffc 219 // remember the calibrated minimum proximity count
mjr 113:7330439f2ffc 220 this->minProxCount = config.plunger.cal.raw0;
mjr 113:7330439f2ffc 221 this->maxProxCount = config.plunger.cal.raw1;
mjr 113:7330439f2ffc 222 this->parkProxCount = config.plunger.cal.raw2;
mjr 113:7330439f2ffc 223
mjr 113:7330439f2ffc 224 // figure the scaling factor for distance calculations
mjr 113:7330439f2ffc 225 calcScalingFactor();
mjr 113:7330439f2ffc 226 }
mjr 113:7330439f2ffc 227
mjr 113:7330439f2ffc 228 // Begin calibration
mjr 113:7330439f2ffc 229 void VCNL4010::beginCalibration()
mjr 113:7330439f2ffc 230 {
mjr 113:7330439f2ffc 231 // reset the min/max proximity count to the last reading
mjr 113:7330439f2ffc 232 calibrating = true;
mjr 113:7330439f2ffc 233 minProxCount = lastProxCount;
mjr 113:7330439f2ffc 234 maxProxCount = lastProxCount;
mjr 113:7330439f2ffc 235 parkProxCount = lastProxCount;
mjr 113:7330439f2ffc 236 }
mjr 113:7330439f2ffc 237
mjr 113:7330439f2ffc 238 // End calibration
mjr 113:7330439f2ffc 239 void VCNL4010::endCalibration(Config &config)
mjr 113:7330439f2ffc 240 {
mjr 113:7330439f2ffc 241 // save the proximity count range data from the calibration in the
mjr 113:7330439f2ffc 242 // caller's configuration, so that we can restore the scaling
mjr 113:7330439f2ffc 243 // factor calculation on the next boot
mjr 113:7330439f2ffc 244 config.plunger.cal.raw0 = minProxCount;
mjr 113:7330439f2ffc 245 config.plunger.cal.raw1 = maxProxCount;
mjr 113:7330439f2ffc 246 config.plunger.cal.raw2 = parkProxCount;
mjr 113:7330439f2ffc 247
mjr 113:7330439f2ffc 248 // calculate the new scaling factor for conversions to distance
mjr 113:7330439f2ffc 249 calcScalingFactor();
mjr 113:7330439f2ffc 250
mjr 113:7330439f2ffc 251 // Set the new calibration range in distance units. The range
mjr 113:7330439f2ffc 252 // in distance units is fixed, since we choose the scaling factor
mjr 113:7330439f2ffc 253 // specifically to cover the fixed range.
mjr 113:7330439f2ffc 254 config.plunger.cal.zero = 10922;
mjr 113:7330439f2ffc 255 config.plunger.cal.min = 0;
mjr 113:7330439f2ffc 256 config.plunger.cal.max = 65535;
mjr 113:7330439f2ffc 257
mjr 113:7330439f2ffc 258 // we're no longer calibrating
mjr 113:7330439f2ffc 259 calibrating = false;
mjr 113:7330439f2ffc 260 }
mjr 113:7330439f2ffc 261
mjr 113:7330439f2ffc 262 // Power law function for the relationship between sensor count
mjr 113:7330439f2ffc 263 // readings and distance. For our distance calculations, we use
mjr 113:7330439f2ffc 264 // this relationship:
mjr 113:7330439f2ffc 265 //
mjr 113:7330439f2ffc 266 // distance = <scaling factor> * 1/power(count - <DC offset>) + <scaling offset>
mjr 113:7330439f2ffc 267 //
mjr 113:7330439f2ffc 268 // where all of the constants in <angle brackets> are determined
mjr 113:7330439f2ffc 269 // through calibration.
mjr 113:7330439f2ffc 270 //
mjr 113:7330439f2ffc 271 // We use the square root of the count as our power law relation.
mjr 113:7330439f2ffc 272 // This was determined empirically (based on observation). This is
mjr 113:7330439f2ffc 273 // also the power law we'd expect from a naive application of physics,
mjr 113:7330439f2ffc 274 // on the principle that the observed brightness of a point light
mjr 113:7330439f2ffc 275 // source varies inversely with the square of the distance.
mjr 113:7330439f2ffc 276 //
mjr 113:7330439f2ffc 277 // The VCNL4010 data sheet doesn't specify a formulaic relationship,
mjr 113:7330439f2ffc 278 // which isn't surprising given that the relationship is undoubtedly
mjr 113:7330439f2ffc 279 // much more complex than just a power law equation, and also because
mjr 113:7330439f2ffc 280 // Vishay doesn't market this chip as a distance sensor in the first
mjr 113:7330439f2ffc 281 // place. It's a *proximity* sensor, which means it's only meant to
mjr 113:7330439f2ffc 282 // answer a yes/no question, "is an object within range?", and not
mjr 113:7330439f2ffc 283 // the quantitative question "how far?". So there's no reason for
mjr 113:7330439f2ffc 284 // Vishay to specify a precise relationship between distance and
mjr 113:7330439f2ffc 285 // brightness; all we have to know is that there's some kind of
mjr 113:7330439f2ffc 286 // inverse relationship, since beyond that, everything's just
mjr 113:7330439f2ffc 287 // relative. The data sheet does at least offer a (low-res) graph
mjr 113:7330439f2ffc 288 // of the distance-vs-proximity-count relationship under one set of
mjr 113:7330439f2ffc 289 // test conditions, and interestingly, that graph suggests a rather
mjr 113:7330439f2ffc 290 // different power law, more like ~1/distance^3.1. The graph also
mjr 113:7330439f2ffc 291 // makes it clear that the response isn't uniform - it doesn't
mjr 113:7330439f2ffc 292 // follow *any* power law exactly, but is something more complex
mjr 113:7330439f2ffc 293 // than that. This is another non-surprise, given that environmental
mjr 113:7330439f2ffc 294 // factors will inevitably confound the readings to some degree.
mjr 113:7330439f2ffc 295 //
mjr 113:7330439f2ffc 296 // At any rate, in the data I've gathered, it seems that a simple 1/R^2
mjr 113:7330439f2ffc 297 // power law is pretty close to reality, so I'm using that. (Brightness
mjr 113:7330439f2ffc 298 // varies with 1/R^2, so distance varies with 1/sqrt(brightness).) If
mjr 113:7330439f2ffc 299 // this turns out to produce noticeably non-linear results in other
mjr 113:7330439f2ffc 300 // people's installations, we might have to revisit this with something
mjr 113:7330439f2ffc 301 // more customized to the local setup. For example, we could gather
mjr 113:7330439f2ffc 302 // calibration data points across the whole plunger travel range and
mjr 113:7330439f2ffc 303 // then do a best-fit calculation to determine the best exponent
mjr 113:7330439f2ffc 304 // (which would still assume that there's *some* 1/R^x relationship
mjr 113:7330439f2ffc 305 // for some exponent x, but it wouldn't assume it's necessarily R^2.)
mjr 113:7330439f2ffc 306 //
mjr 113:7330439f2ffc 307 static inline float power(int x)
mjr 113:7330439f2ffc 308 {
mjr 113:7330439f2ffc 309 return sqrtf(static_cast<float>(x));
mjr 113:7330439f2ffc 310 }
mjr 113:7330439f2ffc 311
mjr 113:7330439f2ffc 312 // convert from a raw sensor count value to distance units, using our
mjr 113:7330439f2ffc 313 // current calibration data
mjr 113:7330439f2ffc 314 int VCNL4010::countToDistance(int count)
mjr 113:7330439f2ffc 315 {
mjr 113:7330439f2ffc 316 // remove the DC offset from teh signal
mjr 113:7330439f2ffc 317 count -= dcOffset;
mjr 113:7330439f2ffc 318
mjr 113:7330439f2ffc 319 // if the adjusted count (excess of DC offset) is zero or negative,
mjr 113:7330439f2ffc 320 // peg it to the minimum end = maximum retraction point
mjr 113:7330439f2ffc 321 if (count <= 0)
mjr 113:7330439f2ffc 322 return 65535;
mjr 113:7330439f2ffc 323
mjr 113:7330439f2ffc 324 // figure the distance based on our inverse power curve
mjr 113:7330439f2ffc 325 float d = scalingFactor/power(count) + scalingOffset;
mjr 113:7330439f2ffc 326
mjr 113:7330439f2ffc 327 // constrain it to the valid range and convert to int for return
mjr 113:7330439f2ffc 328 return d < 0.0f ? 0 : d > 65535.0f ? 65535 : static_cast<int>(d);
mjr 113:7330439f2ffc 329 }
mjr 113:7330439f2ffc 330
mjr 113:7330439f2ffc 331 // Calculate the scaling factors for our power-law formula for
mjr 113:7330439f2ffc 332 // converting proximity count (brightness) readings to distances.
mjr 113:7330439f2ffc 333 // We call this upon completing a new calibration pass, and during
mjr 113:7330439f2ffc 334 // initialization, when loading saved calibration data.
mjr 113:7330439f2ffc 335 void VCNL4010::calcScalingFactor()
mjr 113:7330439f2ffc 336 {
mjr 113:7330439f2ffc 337 // Don't let the minimum go below 100. The inverse relationship makes
mjr 113:7330439f2ffc 338 // the calculation meaningless at zero and unstable at very small
mjr 113:7330439f2ffc 339 // count values, so we need a reasonable floor to keep things in a
mjr 113:7330439f2ffc 340 // usable range. In practice, the minimum observed value will usually
mjr 113:7330439f2ffc 341 // be quite a lot higher (2000 to 20000 in my testing), which the
mjr 113:7330439f2ffc 342 // Vishay application note attributes to stray reflections from the
mjr 113:7330439f2ffc 343 // chip's mounting apparatus, ambient light, and noise within the
mjr 113:7330439f2ffc 344 // detector itself. But just in case, set a floor that will ensure
mjr 113:7330439f2ffc 345 // reasonable calculations.
mjr 113:7330439f2ffc 346 if (minProxCount < 100)
mjr 113:7330439f2ffc 347 minProxCount = 100;
mjr 113:7330439f2ffc 348
mjr 113:7330439f2ffc 349 // Set a ceiling of 65535, since the sensor can't go higher
mjr 113:7330439f2ffc 350 if (maxProxCount > 65535)
mjr 113:7330439f2ffc 351 maxProxCount = 65535;
mjr 113:7330439f2ffc 352
mjr 113:7330439f2ffc 353 // Figure the scaling factor and offset over the range from the park
mjr 113:7330439f2ffc 354 // position to the maximum retracted position, which corresponds to
mjr 113:7330439f2ffc 355 // the minimum count (lowest intensity reflection) we've observed.
mjr 113:7330439f2ffc 356 //
mjr 113:7330439f2ffc 357 // Do all calculations with the counts *after* subtracting out the
mjr 113:7330439f2ffc 358 // signal's DC offset, which is the brightness level registered on the
mjr 113:7330439f2ffc 359 // sensor when there's no reflective target in range. We can't directly
mjr 113:7330439f2ffc 360 // measure the DC offset in a plunger setup, since that would require
mjr 113:7330439f2ffc 361 // removing the plunger entirely, but we can guess that the minimum
mjr 113:7330439f2ffc 362 // reading observed during calibration is approximately equal to the
mjr 113:7330439f2ffc 363 // DC offset. The minimum brightness occurs when the plunger is at the
mjr 113:7330439f2ffc 364 // most distance point in its travel range from the sensor, which is
mjr 113:7330439f2ffc 365 // when it's pulled all the way back. The plunger travel distance is
mjr 113:7330439f2ffc 366 // just about at the limit of the VCNL4010's sensitivity, so the inverse
mjr 113:7330439f2ffc 367 // curve should be very nearly flat at this point, thus this is a very
mjr 113:7330439f2ffc 368 // close approximation of the true DC offset.
mjr 113:7330439f2ffc 369 const int dcOffsetDelta = 50;
mjr 113:7330439f2ffc 370 dcOffset = minProxCount > dcOffsetDelta ? minProxCount - dcOffsetDelta : 0;
mjr 113:7330439f2ffc 371 int park = parkProxCount - dcOffset;
mjr 113:7330439f2ffc 372 float parkInv = 1.0f/power(park);
mjr 113:7330439f2ffc 373 scalingFactor = 54612.5f / (1.0f/power(minProxCount - dcOffset) - parkInv);
mjr 113:7330439f2ffc 374 scalingOffset = 10922.5f - (scalingFactor * parkInv);
mjr 113:7330439f2ffc 375 }
mjr 113:7330439f2ffc 376
mjr 113:7330439f2ffc 377 // Read an I2C register on the device
mjr 111:42dc75fbe623 378 uint8_t VCNL4010::readReg(uint8_t registerAddr)
mjr 111:42dc75fbe623 379 {
mjr 111:42dc75fbe623 380 // write the request
mjr 111:42dc75fbe623 381 uint8_t data_write[1] = { registerAddr };
mjr 111:42dc75fbe623 382 if (i2c.write(I2C_ADDR, data_write, 1, false))
mjr 111:42dc75fbe623 383 return 0x00;
mjr 111:42dc75fbe623 384
mjr 111:42dc75fbe623 385 // read the result
mjr 111:42dc75fbe623 386 uint8_t data_read[1];
mjr 111:42dc75fbe623 387 if (i2c.read(I2C_ADDR, data_read, 1))
mjr 111:42dc75fbe623 388 return 0x00;
mjr 111:42dc75fbe623 389
mjr 111:42dc75fbe623 390 // return the result
mjr 111:42dc75fbe623 391 return data_read[0];
mjr 111:42dc75fbe623 392 }
mjr 113:7330439f2ffc 393
mjr 113:7330439f2ffc 394 // Write to an I2C register on the device
mjr 111:42dc75fbe623 395 void VCNL4010::writeReg(uint8_t registerAddr, uint8_t data)
mjr 111:42dc75fbe623 396 {
mjr 111:42dc75fbe623 397 // set up the write: register number, data byte
mjr 111:42dc75fbe623 398 uint8_t data_write[2] = { registerAddr, data };
mjr 111:42dc75fbe623 399 i2c.write(I2C_ADDR, data_write, 2);
mjr 111:42dc75fbe623 400 }