CTIN 534

The McVoting Booth

Here are the BS2 and the Processing codes I used to execute my "McVoting Booth." The voting booth allowed the voter to choose between Bush or Kerry. There was a button for each candidate. The Bush button always worked (to add votes to the Bush side), but the Kerry button worked some of the time, sometimes added votes for Bush instead, and sometimes did nothing at all.

THE BS2 CODE:
********************************************************************************************

SerInPin PIN 0 'serial IN pin (RXD - at the other end: TXD)
SerOutPin PIN 1 'serial OUT pin (TXD - at the other end: RXD)
SerInData VAR BYTE 'number to match to incoming data
SerWait CON 50 'ms to wait for input before timing out
N9600 CON 16468 'BS2 baudmode values: 16468/9600, 16416/19200, 16390/38400
'See SEROUT in the Basic Stamp manual for details.

test3:
PAUSE 100

IF IN2 THEN
SEROUT SEROUTPin, N9600,[DEC 1]
DEBUG "1"
ENDIF

IF IN4 THEN
SEROUT SerOutPin, N9600,[DEC 2]
DEBUG "2"
ENDIF
GOTO test3

********************************************************************************************

PROCESSING CODE:
********************************************************************************************
// McVoting Booth
// by Kellee Santiago

// A phony voting booth that reads off of two buttons.
// votes for Bush all of the time, the other button votes for Kerry sometimes,
// Bush at others, and sometimes does nothing.

// Created 20 Oct 2004

int bushVotes = 0; //declares the variable number of bushVotes and starts it at 0
int kerryVotes = 0; //declares the variable number of kerryVotes and starts it at 0
BFont theFont; //declared the variable of the font as "theFont"
int val; //reads the value off the serial port

void setup() {
beginSerial();//starts reading the serial port
size(400,200);//screensize
theFont = loadFont("Bauhaus.vlw.gz");//declared font - make sure to copy it into project folder!
fill(255,0,0);
stroke(255);
textFont(theFont, 48);

}

void loop() {
background(255);
BImage elephant;//declare image of rep. elephant
elephant = loadImage("tease.republican.gif");//loads image - have copy in project folder!
BImage donkey;
donkey = loadImage("tease.democrat.gif");
image(elephant, 120, 50); //sets the place of the image
image(donkey, 200, 50);

smooth();//smooths out font
fill(255,0,0);
text("bush", 40,75);
text(bushVotes,65,125);
fill(0,0,255);
text("kerry", 260,75);
text(kerryVotes,285,125);
}
void serialEvent() {
val = serial;
println(val);
if(val==49) {
bushVotes++; //reads value off serial port. Processing reads in ASCII, so when the
} //serial port sends out a 1, processing sees a 49.
else
if(val==50) {
if(random(10) < 3) {
kerryVotes++;
if(random(10) > 6){
bushVotes++;
//this is how i set up a basic random generator. When processing gets a 50 (ASCII for 2)
//it randomly generates a number from 1-10. If it's less than 3, Kerry gets a vote. If it's greater
//than 6, Bush gets a vote. Nothing happens if it's 3-6.
}
}
}
}
********************************************************************************************

Processing and BS2

I'm trying to get Processing to read a binary input, here is the reference code:

// Binary Input
// by Mathias Dahlstrom

// Example of a binary input from a BX-24 chip using serial communcation.
// Running this examples requires you have a BX-24 microcontroller
// and peripheral hardware. More information can be found on the tutorial
// pages of Tom Igoe: http://stage.itp.nyu.edu/%7Etigoe/pcomp/examples.shtml
// Make sure to have the correct port selected in the "sketch" menu. Because
// this program uses the serial port, it will not work within a web browser.

// Created 12 February 2003

// State of the circle drawing
boolean circleExpanding = true;

// Size of the circle
float circleSize = 0;

//The setup defines screen size and color setup.
void setup()
{
size(200, 200);
beginSerial(19200);
noStroke();
fill(204);
ellipseMode(CENTER_RADIUS);
}

// The loop checks for what state the circle should be
// drawn into and performs the drawing.
void loop()
{
background(0);

if(circleExpanding) {
ellipse(width/2, height/2, circleSize, circleSize);
circleSize += 0.5;
}else{
ellipse(width/2, height/2, circleSize, circleSize);
circleSize -= 0.5;
}
if(circleSize > width/2) {
circleSize = width/2;
}
if(circleSize < 10) {
circleSize = 10;
}
}

// Function is called when ever a new byte from the
// BX-24 is avaliable for reading.
// It controls what input the user is generating and
// sets the corresponding drawing mode.
void serialEvent()
{
// Checks the ASCII code sent from the basicX chip.
// '48' is the code for '0' and '49' is the code for '1'
if(serial == 0) {
circleExpanding = false;
}
if(serial == 1) {
circleExpanding = true;
}
println(serial);
}
*******************************
Here is my code for BS2:

SerInPin PIN 0 'serial IN pin (RXD - at the other end: TXD)
SerOutPin PIN 1 'serial OUT pin (TXD - at the other end: RXD)
SerInData VAR BYTE 'number to match to incoming data
SerWait CON 50 'ms to wait for input before timing out
N9600 CON 16468 'BS2 baudmode values: 16468/9600, 16416/19200, 16390/38400
'See SEROUT in the Basic Stamp manual for details.

DEBUG CR,"Program starting ...",CR

test:
IF IN2 THEN
HIGH 11
SEROUT SerOutPin,N9600,[DEC 1,CR]
DEBUG "1"
ELSE
LOW 11
SEROUT SerOutPin,N9600,[DEC 0,CR]
DEBUG "0"
ENDIF
GOTO test

************************************

But everytime I run the Processing program, it just makes a circle that expands. Blah!

sources for electronics components

Parallax Basic Stamp microcontrollers, sensors, components, modules, robotics
Acroname sensors, motor, robotics, Brainstem microcontroller
Mondotronics robots & robotics components
Jameco huge selection of electronics components
Digi-Key gargantuan selection of electronics components
All Electronics large selection of surplus electronics; cheap, local.
EarthLCD LCD panels, touchscreens
Electronic Goldmine surplus components, cheap
Images SI Inc sensors, actuators, components

Electronics, Robotics & Security Systems Periodicals

Nuts & Volts
Servo Magazine
Practical Electronics
Circuit Cellar
Robotics World
Security Distribution Magazine
Security Magazine
Security World

basic supplies & tools from Radio Shack

Supplies:

• Rosin-Core Solder
  
• Solid Core 22-Gauge Hookup Wire
  
• Breadboard
  
• 220 ohm resistors
  
• 10k resistors
  
• 22k resistors
  
• 0.01µF Ceramic Capacitors
  
• Photoresistors
  
• 9-pin Female D-Sub Connector
  
• Hood for D-Sub Connector

• Wire Strippers
  
• Wire Cutters
  
• Helping Hands

Instructions for making a serial communication cable

To program a Basic Stamp, you can use the 9-pin RS232 serial port that's built in to the carrier board. However, to communicate between the Stamp and a multimedia tool (such as Director, Max/MSP or Processing), you'll need to build a serial cable that ends in bare wires, so that you can connect it directly to two Stamp I/O pins, which you'll use for serial input and output.

Here is a diagram of the cable you'll need to build:

Following are detailed instructions for one method of making this cable.

Use a 9 pin female D-sub connector [Radio Shack 276-1538].
The solder terminals are numbered from left to right, top row first.

You will want to find some way to hold the connector in place while
you solder it (such as a vice, a clamp, a weight, or a piece of tape).
Use .032 diameter light-duty rosin-core solder [Radio Shack 64-005].
Fill terminals 2, 3 and 5 with solder. (Heat the terminal with the soldering
iron and then hold the solder to the terminal until it flows into it).

I recommend using a green wire for ground [5],
a black wire for BS2 serial in [3], and a red wire
for BS2 serial in [2]. Strip 1/4 inch of insulation
on each wire. Coat the bare wire with solder.

Reheat the solder in each terminal.

When it is liquified, push the appropriate wire
into the terminal and hold it until it hardens.

I recommend soldering the necessary 22K resistor
inline with the BS2 serial in cable.

That's it. Now you're ready to test communications
between the Stamp and your authoring tool.

Communicating between the Stamp and an authoring tool

1. Connect the black wire (the one with the 22k resistor) from your serial communication cable to the Stamp's Pin 0. Connect the red wire to the Stamp's Pin 1. Connect the green wire to ground.
2. Load the following program into your Stamp programming software and download it to the Stamp: serialCableTest.bs2
3. The Stamp should print to the debug window: "Program starting ...", and then every few seconds "Waiting for serial input ..."
4. Remove the programming cable from the Mac/PC's serial port, and replace it with the communication cable (the one that's connected to pins 0, 1 and Ground).
5. Now load one of the following three programs into your chosen authoring tool:
   • For Max/MSP/Jitter: serialCableTestMax.pat (should work with any version of Max)
   • For Director: serialCableTest.dir.
     NOTE: If SerialXtra hasn't been installed, you will need to download and install it. It will run in "authoring mode" for free.
   • For Processing: serialCableTestProcessing.pde
6. Before you run any of these programs, make sure you've selected the correct serial port.
   • Max/MSP/Jitter: By sending the serial object a "print" message, you can determine by letter (a, b, c, d, etc) which port is which and then replace the parameter in the serial object.
   • Director: Typing "put findports()" into the message window lists all available ports. Replace "USA191" with the correct port (if you are using a Keyspan adapter, read the comments for some useful details).
   • Processing: make sure to select the correct serial port from the Sketch menu before running the program.
7. Run the program. Your authoring tool should initiate a two-way communication with the Stamp, sending it the number 100 to trigger the next count from 0 to 400 and back again.

Reading a variable resistor with the Basic Stamp

Here is a diagram of the circuit you will need to build to use the BS2 command RCTIME to read any variable resistor (such as a potentiometer, photoresistor, bend sensor, force sensing resistor, etc).

The following Basic Stamp file demonstrates the use of RCTIME to read a variable resistor.

resistor.bs2

Reading various sensors with the BS2

Bend Sensor
Accelerometer
Force Sensing Resistor
PIR Motion Detector

sensor sources

Bend Sensor
PIR Motion Detector Module
Force Sensing Resistor
Dual Axis Accelerometer
Ultrasound Rangefinder
Thermistors
Tilt Sensor
Digital & Analog Compass

circuit diagram for reading a switch with the BS2

troubleshooting Basic Stamp programs

Things to try if something isn't working:

• Make sure the pin numbers in your code match the pin numbers in your circuit.
  
• Make sure that your connections are connected on your breadboard - it's easy to mistakenly plug something into an adjacent row.
  
• Make sure you've selected the correct serial port.
  
• On the Mac, run Keyspan Serial Assistant (found in the Applications folder) to make sure that your Keyspan USB Adaptor is being recognized.
  
• Make sure you've selected the correct flavor of Basic Stamp.
  
• Remember, VDD = +5V, VSS = ground
  
• Make sure you are formatting your variables correctly when you print them out with DEBUG or send them over the serial port as SEROUT. Numbers default to bytes, you will often want to format them as integers using DEC.
  
• Try pressing the RESET button on the Stamp board.
  
• Put in lots of DEBUG statements so that you can pinpoint the problem.
  
• Try quitting MacBS2 and restarting; on a couple of occasions, I've had it stop communicating with the Stamp while appearing to still be working.
  
• I strongly recommend using red wire for connections to +5V, green wire for connections to ground, and black (or other colors) for connections to input/output pins.
  

links to Basic Stamp software

Parallax Basic Stamp Editor 2.1 for Windows
MacBS2 Editor for OS X
Basic Stamp Tokenizer MacBS2 should install this automatically, but it doesn't
SerialXtra for Director