Arduino Archives - Near Future Laboratory

3Difficult

Bleecker has been pestering me to write this for a while now, but I’ve been wrestling with my point of view. Matt Webb has written a lovely piece here about the evolving notion of “product”, which has spurred me on, so let’s give it a go.

Matt Ward recently reminded me of an awkward conversation I had with BERG’s Matt Jones (there are a lot of Matt’s in here) about what constitutes a “product”. I steadfastly defended the tangible, but Jones was more fluid with his definition including services, content, the digital and the physical. I’m happy to admit that in retrospect I was wrong – clearly wrong, but why was I so inflexible? Why was I so dogmatically fixated on objects as the be-all and end-all definition of a product? My defensiveness began to bother me until I realized recently that I wasn’t defending an idea, I was defending my trade.

I like things, I make and draw things, things you can touch, hold, sit in or on. Things made of stuff, things hewn from bigger lumps of other stuff or molten stuff squeezed into holes. I’m an industrial designer at heart, and I’m saddened by what’s happened to my craft. We were once the kings of things, but for a variety of reasons I think we’re in danger of being left behind. As Bueller said “life moves pretty fast, if you don’t stop and look around once in a while you could miss it”.

In the early years of the 21^st century, the Industrial Design world fell to sleep. Whilst it slept a new breed of digital designers emerged, keen to render their ideas in three dimensions. Tools developed quickly, became cheaper and more ubiquitous, and whilst the industrial designers gazed into their huge screens to interrogate the acceleration of a curve across a surface, other things began to appear. Real things made of plastic and metal, with blinking lights and power cords. But these things weren’t from the hands of industrial designers, they were from the hands of the Bay area startups, the digital design labs, hell even the ad agencies.

Making became the talk of the town, and to some extent it still is. We’re in the first stumbling days of the Internet of Things, and are increasingly seeing the paper thin definition between digital and tangible falling away. It’s all up for grabs, and some are grabbing more than others. The more groovy folks I know from the digital world fully understand the difficulties and realities of shipping products, and appreciate the unique skills of a good industrial designer, but there are many who don’t. They see a world of instantly printed, maker bot-ed, 3D sintered, laser cut products, and see no need for a separate skilled individual.

Let’s take a little step back. Remember Flash when Macromedia had the reins? Remember how excited everyone was? A generation of graphic designers found they were able to simply make things move on screen, in a browser, online. Many of them made a mental and professional leap and began referring to themselves as ‘web designers’. Some made the leap successfully, but for many the romance was short lived. The reality of actually producing content for the web was way more complex than getting text to float across the screen or making an intro animation. It was hard. It required serious programming chops, it was like a whole different profession. For this reason, many of the graphic designers I knew returned to their poster design, font development and annual reports, leaving web development to those more experienced and capable of delivering it.

Today’s emergent manufacturing tools are tantalizing indeed, and have given designers of all ilks access to manufacturing techniques hitherto out of technical or financial reach. It’s now simple for a couple of fairly inexperienced guys to feasibly produce products for sale, which is fantastic, but let’s take a critical look at a few of these products. How many of you have invested in a cool thing on Kickstarter only to receive constant emails about how expensive tooling is, or how hard it is to source PSU’s, or how the team massively under-budgeted the production? There have been many projects which simply ground to a halt because the Matter Battle was just too tough, before we even get into the debating the dubious legal position of these devices (CE mark anyone?)

Rapid prototyping techniques are to real products what the play-doh fun factory is to real manufacturing. Things need to exist with integrity rather than just to exist, there are standards which need to be maintained. A rapid printed thing is cool, but to produce a product for mass consumption requires a whole new level of thinking and experience. A good industrial designer can provide this.

Before we get carried away, this needs to be a two way deal. Industrial designers need to wake up and embrace the ebullient folks in the digital world, and work together to deliver real things well. Industrial designers have tended to shy away from the scary worlds of UI, UX, web development and programming, as if they were some alien entities. I see industrial design moving from an experimental realm and into a delivery function, where surfaces are created to ‘skin’ the doohickey spat out from an engineering or development center. That’s not good enough. As industrial designers we need to understand that what we know how to do is golden. We should join in, get involved, build ideas together with digital designers rather than steadfastly holding our corner. We need to do this soon, because the digital guys are keen, and we’re the dinosaurs.

If industrial design is to survive beyond a word of styling and surfaces it needs to embrace the joie de vivre of our digital design brethren, and if you are an Arduino tinkering, web-centric designer, I’d encourage you to look beyond those white dusty 3D things your friends are all excited about. I fully embrace the emergent era of the post-disciplinary designer, but we have to be honest with ourselves and understand specialisms.

Making things is hard. Really hard. Don’t let anyone tell you anything different.

The Design, Art, Technology & History of Arduino

That little guy up above has finally got its own academically written *History. The Arduino is historical! That means something. It means that it is significant enough to warrant a retrospective look back on its when and where and who kinds of questions. I’m glad that’s been done. There are good stories swirling around about Arduino — cafe-bar style stories and anecdotes that you’ll get from the Arduino Wizards like Massimo and Tom and Casey and Golan and Tod. Now Alicia Gibbs has written her masters thesis called New Media Art Design and the Arduino Microcontroller. It’s all about the history and why-for of the Arduino.

The Arduino microcontroller is a malleable tool used in art and design. Started as an educational prototyping tool it contiues to expand due to the thriving community and open source nature. Because open source initiatives allow for modification, derivatives, and sharing of intellectual property, artists and designers can evolve new Arduino-based microcontrollers specified to their work.

Why do I blog this? Alicia sent this to me a couple of months back and I keep trying to find it in my bottomless email database and everytime I do, I forget to blog it so I can have an easy place to find it when I need it. Now — here it is.
Continue reading The Design, Art, Technology & History of Arduino

LIS302DL. A 3 Axis Accelerometer

Ooooh. Those code jockeys in the Laboratory have been mucking about in the ol’ locker room, giving each other rat-tails, chucking firecrackers in the halls and having a good horsin’ around. Smoking cigarettes and drinking cheap booze. Everything. Stink bombs in the girl’s room. Whatever. It’s a regular Lord of the Flies fest on the electronics wing of the Near Future Laboratory. And, look what we found! Some pole dancin’ hardware porn! Step right up! Don’t crowd..

In reverent honor of my friends and chums who are holding forth with Sketching in Hardware 09 in London and for the solemn sadness I have for not being able to participate this year, I hereby drop some code and hardware science up on this piece of blog with a dozen or so lines of Arduinoness meant to articulate and instrumentalize the wonderful ST Micro LIS302DL 3 axis accelerometer, delivered here via the Sparkfun breakout board. Without further ado, but with plenty of firmware nakedness, here’s the sketch..*slug* this one’s for you, Sketchers..*sob*

#include

// TWI (I2C) sketch to communicate with the LIS302DL accelerometer
// Using the Wire library (created by Nicholas Zambetti)
// http://wiring.org.co/reference/libraries/Wire/index.html
// On the Arduino board, Analog In 4 is SDA, Analog In 5 is SCL
// These correspond to pin 27 (PC4/ADC4/SDA) and pin 28 (PC5/ADC5/SCL) on the Atmega8 and Atmega168
// The Wire class handles the TWI transactions, abstracting the nitty-gritty to make
// prototyping easy.

// We've got two accelerometers connected. You configure the address of each one
// by some wiring
int address_1 = 0x1C; // SDO on the LIS302DL connected to GND makes it at I2C address 0x1C
int address_2 = 0x1D; // SDO/MISO on the LIS302DL connected to VCC makes it at I2C address 0x1D
void setup()
{
  // we'll use the serial port to spit out our data
  Serial.begin(9600);

  byte tmp;

  Wire.begin(); // join i2c bus (address optional for master)


  // Read from the "WHO_AM_I" register of the LIS302DL and see if it is at
  // the expected address.
  // If it is not, spit out a useful message on the serial port. We'll get
  // erroneous data from querying this address, though.
  Wire.beginTransmission(address_1);
  Wire.send(0x0F);
  Wire.endTransmission();
  Wire.requestFrom(address_1,1);
  while(Wire.available()) {
   tmp = Wire.receive();
   if(tmp != 0x3B) {
     Serial.print("Problem! Can't find device at address "); Serial.println(address_1, HEX);
     delay(1000);
   } else {
  // configure the device's CTRL_REG1 register to initialize it
  Wire.beginTransmission(address_1);
  Wire.send(0x20); // CTRL_REG1 (20h)
  Wire.send(B01000111); // Nominal data rate, Device in active mode, +/- 2g scale, self-tests disabled, all axis's enabled
  Wire.endTransmission();
   }
  }


  // Read from the "WHO_AM_I" register of the second LIS302DL and see if it is at
  // the expected address.
  // If it is not, spit out a useful message on the serial port. We'll get
  // erroneous data from querying this address, though.
  Wire.beginTransmission(address_2);
  Wire.send(0x0F);
  Wire.endTransmission();
  Wire.requestFrom(address_2,1);
  while(Wire.available()) {
   tmp = Wire.receive();
   if(tmp != 0x3B) {
     Serial.print("Problem! Can't find device at address "); Serial.println(address_2, HEX);
     delay(1000);
   } else {

  // configure the device's CTRL_REG1 register to initialize it
  Wire.beginTransmission(address_2);
  Wire.send(0x20); // CTRL_REG1 (20h)
  Wire.send(B01000111); // Nominal data rate, Device in active mode, +/- 2g scale, self-tests disabled, all axis's enabled
  Wire.endTransmission();
   }
  }
}

void loop()
{
  Serial.print("1:"); read_acceleration(address_1);
  Serial.print("2:"); read_acceleration(address_2);
}

void read_acceleration(int address) {
  byte z_val_l, z_val_h, x_val_l, x_val_h, y_val_l, y_val_h;
  int z_val, x_val, y_val;
  Wire.beginTransmission(address);
 // Now do a transfer reading one byte from the LIS302DL
 // This data will be the contents of register 0x29, which is OUT_X
  Wire.send(0x29);
  Wire.endTransmission();
 Wire.requestFrom(address, 1);
  while(Wire.available())
 {
   x_val = Wire.receive();
 }
 // This data will be the contents of register 0x2B which is OUT_Y
 Wire.beginTransmission(address);
 Wire.send(0x2B);
 Wire.endTransmission();
 Wire.requestFrom(address, 1);
 while(Wire.available())
 {
    y_val = Wire.receive();
 }

 // This data will be the contents of register 0x2D, which is OUT_Z
 Wire.beginTransmission(address);
 Wire.send(0x2D);
 Wire.endTransmission();
 Wire.requestFrom(address, 1);
 while(Wire.available())
 {
    z_val = Wire.receive();
 }

 // I want values that run from {-X to 0} and {0 to +X}, so a little bit math goes on here...
 if(bit_is_set(x_val, 7)) {
   x_val &= B01111111;
   x_val = -1*x_val + 128;
   x_val *= -1;
 }

if(bit_is_set(y_val, 7)) {
   y_val &= B01111111;
   y_val = 128 - y_val;
   y_val *= -1;
 }

 if(bit_is_set(z_val, 7)) {
   z_val &= B01111111;
   z_val = 128 - z_val;
   z_val *= -1;
 }

 Serial.print(x_val); Serial.print(":");Serial.print(y_val); Serial.print(":"); Serial.println(z_val);
}

What’s going on here? Well, straightforward silliness and hardware gafflin’. Two accelerometers on the I2C bus just cause. It looks like this is as many as you can have on there, unless you do some shenanigans or create a second bus with some cleverness.

The hardware spec on the device (Which. You. Should. Read.) explains that, if we’re going to talk to these things using the I2C bus we need to wire CS to the high end of the logic rail, so VCC. This tells the device that we’ll be using I2C protocol. Then we need to address the device. If we connect the MISO (master in, slave out) pin to GND, then the address will be 0x1C. If we connect the MISO pin to VCC, then the address will be 0x1D. So, MISO, in the I2C configuration, controls the least significant bit of the address. This way, without further mucking about, we can have two accelerometers on the bus, which is probably one more than most situations demand, but just in case.

If I were to connect more than two, I would probably go ahead and use the three-wire protocol and have one microcontroller pin per accelerometer dedicated for chip-select (CS). Fortunately, this device supports three-wire protocols, or the SPI protocol.

The Arduino code example above does some simple preambling — initializing the two devices after making sure they are there. Then it just loops forever, reading accelerometer data from each of the three axes of each one, doing a little simple bitwise arithmetic to make the data from a negative value for negative g (upside down in most situations) to positive g (right side up, in most situations). The initialization stage sets the accelerometer range — that is, the max/min values it will read — to +/- 2g. (The device will support +/- 8g according to the specifications.)

There are some cool additional features that I don’t play with, including some interrupts that can be triggered if the device falls suddenly, or if it is “clicked/tapped” or “double-clicked/double-tapped”, which is kinda cool, I guess. If you can come up with a non-gratuitous scenario. Which is probably harder than it sounds. But, even in your gratuitous-I-double-click-my-glass-of-Porto-to-signal-the-waiter-I-need-more-Porto the device will save you the hassle of trying to do this sort of interaction semantics in firmware and get you back to finishing what you were doing in the first place.

Why do I blog this? Notes on the integration of hardware to firmware to ideas. This time with a “new” accelerometer that has some pretty neat features. After this, we’ll be going to paper-pulp and line drawings for a bit folks.

Laboratories, Accelerometers And Kitchen Crockery

The Memsic 6202 Accelerometer, fresh out o’the skillet.

We’ve been out of the Laboratory proper — the place where things are constructed and soldered and heated up — for a bit now, not because we don’t go in there, or we haven’t been doing things that will go in there. No, rather, or because of a variety of curiosities that have attracted our attention and, in that way, have slung us around to be more in the mode of reading and observing so as to launch into the next, “next vector of interests.” We believe strongly here allowing things to stew and simmer in the reading-writing-intellect as much as in the making-things section of the young noggin. There is much good that comes from the process of tinkering as well as, err..think-ering, both simultaneously, perhaps. Doing things to help think through what one finds curious or helpful, tinkering our way to new, more habitable world. Making things is a great way to learn. It is also a great way to think-things-through. Rather than the still idle of pondering, as an adjunct to the quiet sit in the cafe — making something that helps add some weight to the thought. Perhaps closer to The Craftsman by Richard Sennett.

The interests today swing around the ways of framing things, explaining and demonstrating and communicating, especially future fictions, perhaps designed fictions, as a way of describing the sometimes peculiar imaginings that get brought upstairs from the boys in the basement in the Bureau of Coming Attractions. We have our Bureau of Urban Scouting, evolving its own practice of observation and, perhaps of more interest, a variety of instruments and procedures for seeing the world sideways. Nicolas and I are in the final stages of this short essay for the Situated Technologies project that will include this topic. Literally in the final stages. As in, right now I should be editing a Google Doc rather than writing this, but I let the morning coffee lead me.

So, this is all to say that this blog swerves constructively, probably baffling all eighteen readers into wondering — what the heck is going on here? Where is the editorial consistency? Where’s my code/diagrams/schematics?

To this I only ask that you look for such things even here, as they are always in-the-making, becoming the hardware in the midst of the thinking-through, in the ideas.

As the curiosity-seeker Jack Schulze recently intoned in a wonderfully Talmudic way — "No one cares about what you think, unless you do what you think. No one cares what you do, unless you think about what you do. No one ever really cares what you say."

This may explain Jack’s characteristically quiet demeanor. We’re quite verbally agitated here, so we’ll let the last one slip by us. But, the yammering is the thinking-making-doing, sometimes in words, sometimes in thoughts, sometimes in the materialization of our imagination.

With this said, in response to Reader Number Fourteen’s request this morning for “some code”, I share with you this little thing: Code to Test the Memsic 6202 Accelerometer. You may remember this little guy. We used it in our early foray into fabricating surface-mount electronics. With kitchen skillets. We learned this bit of tinker-y hacker-y from our friends over at Spark Fun. It works great. And it’s cheap as rocks.

I can’t say we were super excited about this particular accelerometer, but that’s okay. It’s just an accelerometer after all. If you follow us down toward the foxhole of these things, you’ll find a whole world of accelerometer fanatics with plenty of material to fuss with — smart accelerometers, accelerometers that let you know when they’re falling, accelerometers that tell you the time as well as whether they’re falling, etc. You’ll find some material buried here in the blog archives, to be exhumed with the right incantation of search and category selection parameters.

This code was written for the Atmel 8-bit microcontrollers that live on the Arduino board. It also makes use of the Wire library for the Arduino, and, as well, the two-wire interface (TWI) hardware support on those microcontrollers, making the whole thing pretty easy-peasy.

#include
#include


// TWI (I2C) sketch to communicate with the Memsic MXC6202J accelerometer
// Using the Wire library (created by Nicholas Zambetti)
// http://wiring.org.co/reference/libraries/Wire/index.html
//
// On the Arduino board, Analog In 4 is SDA, Analog In 5 is SCL
// These correspond to pin 27 (PC4/ADC4/SDA) and pin 28 (PC5/ADC5/SCL) on the Atmega8
// Know You're Microcontroller. Check Which One Is On Your Board/Arduino.
// Newer (as of May '09) Arduinos Use The Atmega168. Can You See It?
// The Wire class handles the TWI transactions, abstracting the nitty-gritty to make
// prototyping easy.

void setup()
{
  Serial.begin(9600);
  Serial.println("Naah??");
  Wire.begin(); // join i2c bus (address optional for master)
}

void loop()
{

  byte x_val_l, x_val_h, y_val_l, y_val_h;
  int x_val, y_val;
// transmit to device with address 0x1D
// according to the MXC6202xMP datasheet, the TWI/I2C address of is fixed
// at the factory depending on what the "x" in the part name is
// Read The Data Sheet section "I2C Bus Data Transfer" for descriptions
// of what the part expects to receive as its address. If you do not understand
// how this works, you are guaranteed to get lost/confusted/frustrated.
// 00010000b is the address of the chip I have, or 0x10

  // a little fuzzy in my recollection here. I think this initializes the chip
  // by setting some bits in the Memsic device's 8-bit internal register
  // Not 100% sure why I initialize two bytes.
  Wire.beginTransmission(0x10);
  Wire.send(0x00);
  Wire.send(0xF0);
  Wire.endTransmission();

  delay(100);

  Wire.beginTransmission(0x10);
  Wire.send(0x00);
  Wire.endTransmission();

  // request five bytes of data
  // first one is the internal register, we can ignore that, but lets look at it for giggles
  Wire.requestFrom(0x10,5);
  while(Wire.available()) {
    Serial.print(Wire.receive(), HEX); // drop the internal register on the floor..
  }
  Serial.println("****");

  // next byte is the MSB of the X axis acceleration
  if(Wire.available()) {
    x_val_h = Wire.receive();
  }
  // next byte is the LSB of the X axis acceleration
  if(Wire.available()) {
    x_val_l = Wire.receive();
  }
  // next byte is the MSB of the Y axis acceleration
  if(Wire.available()) {
    y_val_h = Wire.receive();
  }
  // next byte is the LSB of the Y axis acceleration
  if(Wire.available()) {
    y_val_l = Wire.receive();
  }
  // cobble all of this together into 16 bit acceleration values
  // doing the usual bit-shift polka
  x_val = (x_val_h << 8); x_val |= x_val_l;
  y_val = (y_val_h << 8); y_val |= y_val_l;
  // spit it all out across the serial port so we can see it
  Serial.print(x_val_h, HEX); Serial.print(" "); Serial.print(x_val_l, HEX); Serial.print("n");
  Serial.print(y_val_h, HEX); Serial.print(" "); Serial.print(y_val_l, HEX); Serial.print("n");
  Serial.println("===");

 Wire.endTransmission();

 // loop and do it again.
  delay(200);
}

Continue reading Laboratories, Accelerometers And Kitchen Crockery

Finding The Way – HMC6352 Digital Compass

Since I was asked, and asked again, I’ll toss this technotopia solutions nugget to demonstrate that, despite the evidence demonstrated by recent public appearances and weblog postings, we here at the Laboratory are in fact still fully engaged in connecting wires amongst components. Components take a variety of forms, as do the wires. Sometimes bits of silicon strongly encased in hermetically sealed plastic. Other times, cultural components made of different materials. Observations and their conclusions take a variety of paths and sources of inspiration. We enjoy looking at curious people-practices, inspecting them for insights and stories to be told with a variety of resources: objects, images, words.

And so on. More on this point later.

In the meantime, an eager follower has asked for some simple advice that could have been dispatched in an electronic mailing. Instead, The Near Future Laboratory resources room has decided to fold that information into a weblog “posting.”

Wayfinding, of the digital variety has become exceptionally straightforward for those who are okay with writing a dozen or so lines of code for the handy-dandy Arduino and this HMC6352 digital compass which is available as a breakout board off the rack from our friends at Sparkfun.

The compass will give you a perpetual stream of degrees-heading from magnetic north and has interesting adjustments to let you make offset corrections and that sort of thing. It works simply, as all such things should be. It’s a TWI/I2C device, so you get it on the I2C bus, and send commands to its address (42h). Easy-peasy. If you’re doing anything like setting a RAM or EEPROM register, you send the approrpriate command and address. But, for the most part, you’ll just want to tell it to send heading data, right? That’s simple — send the letter ‘A’ (41h) and back comes the heading data. That’s it. Send an ‘A’, get a heading. Send an ‘A’..get a heading. Over and over, or as often as necessary.

Done.

Here’s some Arduino code to get you going!


#include

// http://wiring.org.co/reference/libraries/Wire/index.html
// On the Arduino board, Analog In 4 is SDA, Analog In 5 is SCL
// These correspond to pin 27 (PC4/ADC4/SDA) and pin 28 (PC5/ADC5/SCL) on the Atmega8
//
// These correspond to pin 27 (PC4/SDA/PCINT12/Analog Input 4) and pin 28 (PC5/ADC5/SCL/PCINT13/Analog Input 5) on the Atemga168
// The Wire class handles the TWI transactions, abstracting the nitty-gritty to make
// prototyping easy.

int address = 0x42 >> 1;
 int reading;
void setup()
{
  // this for debugging the data
  Serial.begin(9600);
  // set up
  CLKPR = (1<<clkpce);
  CLKPR = 0;
  // initialize the HMC6352
  Wire.begin(); // join i2c bus (address optional for master)
}

void loop() {

  Wire.beginTransmission(address);
  Wire.send('A');
  Wire.endTransmission();
  //delay(10);
  Wire.requestFrom(address, 2);

   if(2 <= Wire.available())    // if two bytes were received
  {
    reading = Wire.receive();  // receive high byte (overwrites previous reading)
    reading = reading << 8;    // shift high byte to be high 8 bits
    reading += Wire.receive(); // receive low byte as lower 8 bits
    reading /= 10;
    Serial.println(reading);   // print the reading
  }

//  delay(50);
}

Continue reading Finding The Way – HMC6352 Digital Compass

Autonomous Game Controllers

Continuing on my strange pursuit of designing weird interfaces that disrupt conventional game interaction rituals, I put together a bit more of my “PSX” project. You probably don’t recall, but this is the project where I’ve created a little “dongle” that can fool a PS2 (or Playstation 3, as it turns out..) into thinking that the dongle is actually a Playstation controller. You can also hook up a real Playstation controller to it and it can “read” the controller buttons and joystick and pass that data through, or do whatever you want with it. It appears as an TWI/I2C device to anything that talks to TWI/I2C devices..like my favorite TWI/I2C talking thing — the Arduino.

You can see here that the dongle — the white box with those annoying, huge Playstation connectors on either end, one male, one female — has four wires going into it. Those are for power, ground and the TWI signals, SDA and SCL. The power and ground are necessary because the Arduino (at least this one here) and the dongle run at different voltages. The Arduino is a 5V device, while the dongle is a 3.3V device, so there’s some level shifting going on inside there.

So, that’s all fine. It works, etc. But then the question that’s actually more intriguing than building the thing..what do you do with it?

Well, I have some ideas, including hooking up a bike to it and attaching a giant human form kick-boxing dummy to play old school fighting games. For some early fun and nonsense, I connected a Wii Nunchuck up to it to control Playstation games with Wii-y gestures and stuff. Which could be cool if I find the right game, or spend a little more time thinking things through rather than just writing and revising microcontroller firmware to make a TWI controllable device, and doing Catia to CAD-up and print plastic enclosures.

But, in the meantime, I decided to do an absolutely crucial bit of game science. Something that I am entirely sure is mulled over constantly, but never properly investigated. The question is best stated thusly: how long would it take the Little Prince to roll up an entire room based on a random path algorithm?

How long indeed. Well, short answer is a long time. I let it go for about 70 minutes, after which he had just 10 things to go in a particularly tricky location that required rolling across a narrow bridge. At this point, I took over..but check out the 8x speed video anyway!

Katamari Autonomy from Julian Bleecker on Vimeo

I wrote a quick little Arduino code for my PSX dongle to have the Little Prince roll forward and then, after a few moments, make a random directional change. (Or stop, take a load off and look around the world.)

This was all done by sending TWI commands to the appropriate registers in my little DIY Playstation 2 controller emulator. All the buttons and the joysticks can be emulated as to their state through a series of write-to registers. If there’s a controller stuck in the other side of the dongle, there are a complement of read-from registers so you can see if any of the buttons are pressed and how much the joysticks are displaced. (I set up an “escape” buttons sequence — pressing both L2 and R2 — to bring control back to the normal joystick so I could navigate menus or take control over, which I had to do after I realized, with four items left, the completion of cleaning the room would probably not happen before the universe ran out of steam.)

Here’s the Arduino code. Pretty straight forward Wire / TWI library stuff.


#include
#include "nunchuck_funcs.h"

#define is_bit_clear(a, n) (0 == (a & (1<<n)))
#define is_bit_set(a, n)  (1 == (a & (1<<n))

#define is_button_pressed(a, button) is_bit_clear(a, button)
#define is_button_released(a, button) is_bit_set(a, button)

#define BTN_SELECT 0
#define BTN_L3 1
#define BTN_R3 2
#define BTN_START 3
#define BTN_UP 4
#define BTN_RIGHT 5
#define BTN_DOWN 6
#define BTN_LEFT 7
#define BTN_L2 8
#define BTN_R2 9
#define BTN_L1 10
#define BTN_R1 11
#define BTN_TRIANGLE 12
#define BTN_CIRCLE 13
#define BTN_X 14
#define BTN_SQUARE 15

// register addresses in the PSX I2C device
#define W_BUTTONS_0 0x00 // (, ^, start, R3, L3, select
#define W_BUTTONS_1 0x01 // (square, x, o, triangle, R1, L1, R2, L2)
#define W_RIGHT_X 0x02
#define W_RIGHT_Y 0x03
#define W_LEFT_X 0x04
#define W_LEFT_Y 0x05

#define R_BUTTONS_0 0x12 // (, ^, start, R3, L3, select)
#define R_BUTTONS_1 0x13 // (square, x, o, triangle, R1, L1, R2, L2)
#define R_RIGHT_X 0x14 // a value from 0x00 - 0xFF
#define R_RIGHT_Y 0x15 // a value from 0x00 - 0xFF
#define R_LEFT_X 0x16
#define R_LEFT_Y 0x17

// I2C address of the PSX dongle
int psx_dongle_addr = 0x72;
int j;
void setup()
{
  Serial.begin(9600);
  randomSeed(analogRead(0));
  Wire.begin(); // join i2c bus (address optional for master)


// this is the control register. setting it to 1 means that
// we have to tell the PSX device what data to send to the
// Playstation2. Setting it to 0 means that it simply passes
// through the data from the controller to the PS2. We can
// read the state of the contorller at any time.

writeToAddress(psx_dongle_addr, 0x24, 1);
}

// we'll use count to figure out when to change direction
int count = 0;
int buttons;

// mode is used to indicate either "pass thru" where we can use the
// actually real human controller to control the PS2, or to generate
// data via the PSX dongle.
// pressing both L2 and R2 simultaneously toggles the mode
int mode = 1;
byte randomNumber;

void loop()
{
  byte val;
  count++;
  //Serial.println(count, DEC);
 // 0x70 shows up as either ID $20 or ID $E0 on Propeller

/*******************************************/
/*
  BTN_SELECT = $0001
  BTN_L3 = $0002
  BTN_R3 = $0004
  BTN_START = $0008
  BTN_UP = $0010
  BTN_RIGHT = $0020
  BTN_DOWN = $0040
  BTN_LEFT = $0080
  BTN_L2 = $0100
  BTN_R2 = $0200
  BTN_L1 = $0400
  BTN_R1 = $0800
  BTN_TRIANGLE = $1000
  BTN_CIRCLE = $2000
  BTN_X = $4000
  BTN_SQUARE = $8000
**/


// 0x00 write to BUTTONS_0, 0x12 read from BUTTONS_0
// 0x01 write to BUTTONS_1, 0x13 read from BUTTONS_1
// 0x02 write to RIGHT_X, 0x14 read from RIGHT_X
// 0x03 write to RIGHT_Y, 0x15 read from RIGHT_Y
// 0x04 write to LEFT_X, 0x16 read from LEFT_X
// 0x05 write to LEFT_Y, 0x17 read from LEFT_Y
//Serial.println(getButtons(), HEX);
//int buttons = getButtons();
//Serial.print(buttons, BIN);
//  passThruButtons();

if(count > 512) {
  count = 0;
}
//Serial.println(mode, HEX);

// get the buttons
buttons = getButtons();

// mode is used to indicate either "pass thru" where we can use the
// actually real human controller to control the PS2, or to generate
// data via the PSX dongle.
// pressing both L2 and R2 simultaneously toggles the mode
  if(mode == 1 &&
     is_button_pressed(buttons, BTN_L2) && is_button_pressed(buttons, BTN_R2)) {
    mode = 0;
    delay(1000);
  } else
  if(mode == 0 &&
     is_button_pressed(buttons, BTN_L2) && is_button_pressed(buttons, BTN_R2)) {
     mode = 1;
     delay(1000);
     }
 if(mode == 1) {
passThruAllAndShow();
 }
 if(mode == 0)
  {

  writeToAddress(psx_dongle_addr, W_LEFT_Y, 0x00);
  writeToAddress(psx_dongle_addr, W_RIGHT_Y, 0x00);
  passThruButtons();

  if(count == 512) {
    count = 0;

    randomNumber = random(1,5);
        Serial.print("FLIP! ");
        Serial.println(randomNumber, HEX);
    switch(randomNumber) {
      case 1: case 2: case 6:
        writeToAddress(psx_dongle_addr, W_LEFT_Y, 0x00);
        writeToAddress(psx_dongle_addr, W_RIGHT_Y, 0xAF);
        delay(500);
        break;
      case 3: case 4: case 5:
        writeToAddress(psx_dongle_addr, W_LEFT_Y, 0xAF);
        writeToAddress(psx_dongle_addr, W_RIGHT_Y, 0x00);
        delay(500);
        break;
          default:
         delay(500);
         break;
    }
  }

  /*
writeToAddress(psx_dongle_addr, W_LEFT_X, (float)map(nunchuck_accelx(), (float)0x48, (float)0xB0,
                (float)0x00, (float)0xFF));
writeToAddress(pssx_dongle_addr, W_LEFT_Y, (float)map(nunchuck_accely(), (float)0x48, (float)0xB0,
                (float)0x00, (float)0xFF));

writeToAddress(psx_dongle_addr, W_RIGHT_Y, (float)map(nunchuck_joyy(), (float)0x1D, (float)0xDF,
                (float)0x00, (float)0xFF));
writeToAddress(psx_dongle_addr, W_RIGHT_X, (float)map(nunchuck_joyx(), (float)0x1D, (float)0xDF,
                (float)0x00, (float)0xFF));
*/
}

delay(10);
}


//
int getButtons()
{
int result = 0x00;

result = readFromAddress(psx_dongle_addr, 0x13, 1);
//  Serial.print(result, HEX); Serial.print(" ");
result <> 8)); // MSB
  Wire.send((int)(addr & 0xFF)); // LSB
  Wire.send(data);
  Wire.endTransmission();
}

byte readFromAddress(int twi_addr, int addr, int bytes_to_read)
{
  byte rdata;
 Wire.beginTransmission(twi_addr);
  Wire.send((int)(addr >> 8)); // MSB
  Wire.send((int)(addr & 0xFF)); // LSB
  Wire.endTransmission();
  Wire.requestFrom(twi_addr,bytes_to_read);
  while (Wire.available()) rdata = Wire.receive();
  return rdata;
}

Continue reading Autonomous Game Controllers

A New Logic Analyzer and the HMC6352 I2C Compass

Two things that’ve been sitting on my bench for a good spell — this HMC6352 magnetic compass with an I2C interface, and the Saleae “Logic” logic analyzer. I figured I could combine the two together, showing how I used the Logic to check out the operation of the HMC6352.

First, the HMC6352 is a pretty easy to use magnetic compass with 0.5 degree accuracy. It’s all wrapped up nicely with a pretty normal I2C interface to a bunch of registers on the device, and command-driven queries for reading the compass heading.

The Saleae “Logic” logic analyzer is pretty sweet for debugging I2C as I’ve mentioned in the past. This one is nice and compact, with a reasonable bunch of logic lines for doing simple analysis. I played with this one for a number of projects over the last few months — mostly I2C projects, which is where most of my interface work is these days. But, the “Logic” will also work with a bunch of stock “analyzers” for RS232 and SPI as well, making it pretty versatile for many situations.

The analyzer is a pretty compact package — 1.6″ square and only .36″ high. So, basically miniature for a logic analyzer. It comes with a 9 conductor umbilical along with E-Z-Hook XKM probes that you can use or not, depending on how you’re hooking up to things.

The Logic has a pretty easy-to-use bit of front-end software to handle all the set-up and UI work for the teeny-tiny hardware. It’s a UI that is unlike what you might expect from a bit of Windows-based software. It’s very gooey, using some subtle screen effects and UI elements that, for this OSX guy, are not what I think of when I think of XP. Which is good. It makes using the UI not feel like I’m being forced to drink a Rusty Nail or something for breakfast.

The analyzer samples much quicker than I normally have need for and does so without any problems. I’m usually down in the low range — .2 MHz and 1 M samples is usually plenty for what I’m doing. But, if you need a wider range of samples or a higher sample rate, the analyzer will go all the way up to 24 MHz. Those 9 conductors are 8 data lines plus one ground, so you can analyzer an 8-bit wide bus if you wanted at 24 MHz.

So, I put the Saleae Logic on the HMC6352 circuit to give it a shot. First, the HMC6352 set-up.

Although the HMC6352 has a wide voltage range, I was playing around with a level shifter circuit that was already hooked up to an Arduino on the bench, so I went ahead and just kept that circuit as is. So, the basic set-up is my Arduino I2C lines (SDA and SCL) going through a bi-directional level shifter shifts 3.3V 5V, and then to the HMC6352 SDA and SCL lines. I use yellow wire for SCL and blue wire for SDA.

I ended up using the Saleae Logic to dig a bit deeper into the communication between my microcontroller (an Atmega168 sitting on an Arduino) and the HMC6352 as a way to test out the logic analyzer.

First I wanted to just probe the I2C communication. The basic transaction my Arduino code was doing was to send an “A” to the HMC6352. According to the specification sheet, writing an “A” to the device causes it to return two bytes of data — the high-order and low-order bytes of a 16 bit value indicating the compass’ heading. Easy enough. Here’s the Arduino doing just that. First, it sets up the write to the I2C device at address 0x21. Then it writes an “A” which, in the ASCII table, is the value 0x41. (N.B. The spec sheet says the HMC6352 is at address 0x42 but — and don’t ask me why — sometimes the address specified has to be right-shifted one bit in order to “take”. I mean I sort of know why, but I don’t know why this is the case sometimes — a r/w bit thing or something. Too much to bother with, but a good way to make good use of a logic analyzer when you’re stuck wondering why your device doesn’t seem to be listening to you. I learned this the long way and only had a fancy DSO to try and debug it.)

There it is in the top picture. A simple write to the device at address 0x21 with all the ACKs, meaning whatever is out there, heard us and is acknowledging receipt of the write. And, it looks like we get two bytes of data back — a 0x03 and a 0x64. The first byte will be the high-order byte and the second byte is the low-order byte. 0x0364 is 868, which we normalize by dividing by 10, to get 86.8 degrees. Done. I’m pretty sure that’s that. Finally, the measurement features are pretty cool — useful for confirming clock speeds or verifying a bit train. There’s a good use of a simple, pretty inexpensive ($150) logic analyzer that’ll certainly save you $150 worth of your time many times over. Plus, the small size and convenience of USB make it easy enough to fit on your bench and store away or travel around with when it’s not in use. My only quibble is that it’s only for Windows, but that’s a minor one. I don’t really play too hard in the OS religious wars. I run whatever makes my life easier at whatever moment. So, a $200-ish Windows chassis in the laboratory that just runs a few apps like some CAD software and things like my Propeller coding environment, .NET development, software for test equipment like this and AVR Studio 4 — it just helps me get things done rather than being adamantine about which OS religion I’ll adhere to and, then, not getting anything done except spending time porting things from one OS to another or complaining about how much a Windows license costs or whatever.

Wow. Okay. Off my high horse. Check this logic analyzer out. I can recommend it after using it for a few months.

#include

// http://wiring.org.co/reference/libraries/Wire/index.html
// On the Arduino board, Analog In 4 is SDA, Analog In 5 is SCL
// The Wire class handles the TWI transactions, abstracting the nitty-gritty to make
// prototyping easy.
// This sketch has a HMC6352 attached to the I2C bus, through a bi-directional
// level-shifter circuit.
int address = 0x42 >> 1;
 int reading;
void setup()
{

  Serial.begin(9600);

  CLKPR = (1<<clkpce);
  CLKPR = 0;

  // initialize the TWI / I2C Bus
  Wire.begin(); // join i2c bus (address optional for master)

}

void loop() {

  Wire.beginTransmission(address);
  Wire.send('A');
  Wire.endTransmission();
  //delay(10);
  Wire.requestFrom(address, 2);

   if(2 <= Wire.available())    // if two bytes were received
  {
    reading = Wire.receive();  // receive high byte (overwrites previous reading)
    reading = reading << 8;    // shift high byte to be high 8 bits
    reading += Wire.receive(); // receive low byte as lower 8 bits
    reading /= 10;
    Serial.println(reading);   // print the reading
  }

//  delay(50);
}

Continue reading A New Logic Analyzer and the HMC6352 I2C Compass

Propeller and Arduino

Not the most exciting thing, but an interesting challenge here. I’m trying to get a Parallax Propeller chip to behave nicely as an TWI/I2C slave with the idea that I’d like to create a pretty much black-box interface that’ll allow a TWI/I2C master to control it for stuff. Ultimately I’d like to use the Propeller in the PSX project. It’ll sit in between a Playstation 2 and a normal Playstation controller, and be available as a TWI/I2C slave, so that another device, that doesn’t really care to figure out how to talk to a Playstation 2 or its controllers can make the PSX box with the Propeller in it emulate, for the Playstation, certain button presses, etc. Or, it could “read” over TWI/I2C from the PSX box and find out what the real controller is doing. Or, it could just read or write from a special TWI register address to make the PSX box (with the Propeller in it) just do a “pass-thru” so that the signals just go straight through as if there were nothing in between.

That’s the theory. In practice, setting up this test jig took more time that I would’ve thought.
Continue reading Propeller and Arduino

PSX..Analog Edition

So, this is my analog version of a playful Playstation 2 controller for the PSX project — the one that slows the analog part of the controller down over time so, you know..when I’m playing Katamari Damacy it’s a bit more realistic that the Prince gets tired or during GTA, my guy actually gets tired from running away from liquor store heists and stuff.

I’m looking at two approaches. The first is digital — basically intercepting and modifying the communication between the console and the controller. (I’ve described the protocol, and there’s lots of great, hard-gained information out and about describing how it works.)

It’s a good, playful idea as a kind of theory object, entirely doable, kinda complicated and perhaps a bit of an over-designed solution for a simple idea. What I want is something made (constructed, 3D-printed, wired-up, soldered, fab’d, modeled, fussed-over, troubled-with, a cause of grief, etc.) rather than only just discussed. More than discussing only with words (still the greatest instruments for making things) the object also explicates the tension between physical-digital worlds, or the “real world” and “second life”.

This isn’t something that’s a mass-market product design concept, which should be pretty obvious. (Why is it always assumed that productions from the laboratory are products rather than conversation pieces? I would rather make objects that enter into conversations with a provocation, or enter into discussions, raise questions, help create disruptions by describing new interaction rituals, not making least-common denominator products. These are objects that speak — they create, perpetuate and incite discussions — even inspire new concepts that link 1st life with 2nd life, such as “feeding” characters in games in some fashion, which is closer to the motivation than simply trying to hobble a game character. It’s a theory object. The “theory” embodied in the PSX controller concept here is meant to disrupt the conventional understanding of the relationship between physical activity in 1st Life and virtual-physical-digital activity in 2nd Life digital worlds.)

This is the second, more expeditious design. Basically, I tap right into the PSX controller, putting a microcontroller in between the analog control joysticks and the little FPGA or whatever it is that senses the analog control joysticks. So, my microcontroller determines where the control sticks are and, depending on how long the game’s been played, “dampens” the value, constraining its range.

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It’s a simple “tap” in between, which requires a bit of less-than-elegant de-soldering and pad lifting (or trace cutting) in order to create the cut-in point for the hardware that’ll sense and then spoof the console.

In this case, for testing I used an Arduino, which has enough built-in analog-to-digital converters to sense the positions of the four potentiometers (right-horizontal, right-vertical, left-horizontal, left-vertical) that make up the two joysticks. It also has an I2C/TWI/2-Wire interface that I can use to control four digital potentiometers. The digital potentiometers will appear to be the normal joystick potentiometers only with their values slightly clamped over time to dampen the effects of your normal input.

The joystick potentiometers produce 8-bit values in the interface protocol, and are around 0x80 (or so..) in the middle, when they haven’t been displaced. Here’s a snip from the larger interface protocol showing, from left to right and in the white trace, right-horizontal, right-vertical, left-horizontal, left-vertical. Each value is in the middle range meaning that the joysticks aren’t displaced. If, for example, the right vertical joystick was fully displaced upward, the second value would be 0x00 (full down would be 0xFF.)

I wrote a simple little Arduino sketch below that does a 10-bit analog-to-digital conversion of the right and left vertical potentiometers. Because the PSX controller seems to have a limited, 8-bit range, it’s necessary to dampen the 10-bit value. Just through experimenting, I found that dividing the 10-bit A2D value by 6 (sort of like right-shifting 2 1/2 times), I could get pretty close to what the controller was producing in terms of a range of values. (I don’t quite get to 0, but it’s close enough.)

I then test attenuating the range by using a constraint function built into the Arduino extended library. This function “clamps” the range of a value passed into it, so I can (in another version) gradually constrain the range that the potentiometer can go through.

Effectively, for this example, when either joystick is full up, the range of the digital potentiometer is clamped, so that the value that the controller senses is not quite a full displacement, no matter how far the player pushes it up. (The same works for downward displacement.) In this case, full upward displacement clamps the right vertical to 0x2B (second from left) and the left vertical to 0x36 (fourth from left). (You can see that the horizontal displacements are off-center because the joystick has been moved and isn’t dead-center in the horizontal direction.)

//
// Control the Playstation console
// by spoofing the PSX controller

#include
int RY_Pot = 0;
int LY_Pot = 1;

void setup()
{
  Wire.begin();
  analogReference(EXTERNAL);
  Serial.begin(9600);
}

int val = 0;
int bias = 0;

void loop()
{

  // bias runs between about 23 -90 -  155
 // read the value from the right vertical joystick
  val = analogRead(RY_Pot);

 // transmit to device 0x28
 // which is a DS1803 digital potentiometer
  Wire.beginTransmission(0x28);
// prepare to write to potentiometer-1
  Wire.send(0xAA);
  bias = val/6;
 // Serial.print("RX ");
 // Serial.print(val, DEC);
 // Serial.print(" "); Serial.println(bias, DEC);
 // a bit of fudge..
  if(bias < 30) bias -= 10;
  // sends potentiometer-1 value byte
  Wire.send(constrain(bias+15, 60, 120));
  Wire.endTransmission();

 // do the same thing, for the
 // left vertical joystick
  val = analogRead(LY_Pot);

  Wire.beginTransmission(0x29);
  Wire.send(0xA9);
  bias = val/6;
// Serial.print("RY ");
// Serial.print(val, DEC);
// Serial.print(" ");
// Serial.println(bias, DEC);
  if(bias < 30) bias -= 10;
 // sends potentiometer value byte
  Wire.send(constrain(bias+15, 60, 120));
  Wire.endTransmission();     // stop transmitting

  //delay(100);
}

DS1803 Digital Potentiometer

I’ve been fussing with this digital potentiometer, the DS1803 by Maxim. They’re “digital” because you can control the resistance over its range programmatically, by sending it commands over a 2-Wire (I2C/TWI) serial interface. So, that means that I can hook it up to some microcontroller, like the Arduino, and adjust the resistance in a little program. I chose this one in particular because it can operate at either 3V or 5V, which is convenient, and it comes in a few different models with various resistance ranges. I’m using the DS1803-010, which means it has a range of 0-10K Ohms.

I created a little PCB with two DS1803s on it. Each DS1803 has two potentiometers on it, so I’ve got four on this board. The code for controlling the DS1803 is pretty straightforward. Each one is addressable over the 2-Wire interface, but because we have two on the same interface, I had to configure one to listen to a slightly different address. The details are in the specification sheet, but basically you hardwire the three lines A0, A1, A2 (see the schematic above) to change the address. Effectively you can have up to 8 individually addressable DS1803s on one interface.

In the Arduino source code example below I am only talking with one DS1803 at address 0x28. (if I was talking to to the second one in the schematic, its address was 0x29.) Here I’ve hooked up a logic analyzer to the interface to just make sure we’re communicating. The code below simply adjusts the potentiometer incrementally upward.

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//
// Control the DS1803 Digital Potentiometer

#include <Wire.h>

void setup()
{
  Wire.begin(); // join i2c bus (address optional for master)
}

byte val = 0;

void loop()
{
  Wire.beginTransmission(0x28); // transmit to device 0x28)
  Wire.send(0xAA);            // sends instruction byte,
                               // write to potentiometer-0
  Wire.send(val);             // sends potentiometer value byte
  Wire.endTransmission();     // stop transmitting

  val++;        // increment value
  if(val == 150) // if reached 64th position (max)
  {
    val = 0;    // start over from lowest value
  }
  delay(100);
}