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1  Using Arduino / Interfacing w/ Software on the Computer / Re: VB Comms Failure During Long Jobs on: August 09, 2013, 04:20:17 am
As a very late addendum to this thread, I'd like to add that I have just tried a fairly new notebook (Acer Aspire One running Win 7) borrowed from a friend as a potential purchase, and it had exactly the same problem.

Even with updates, power-saving and USB SelectiveSleepSuspend disabled it still randomly locked the COM port!

What the hell is wrong with modern laptops!!!?

2  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 12, 2012, 04:59:33 am
Absolutely no idea!

I disabled sleep mode/power-saving (even the screen saver), culled all non-essential processes, pulled the network, switched off Wifi/Bluetooth and disabled SelectiveSuspend on the USB ports. I would do a fresh install, but it's such a faff on the Eee PC without a CD-ROM drive. I'll keep the old Acer in the workshop now, the Eee PC can go back to being what it was originally bought for, being m-o-b-i-l-e!
3  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 12, 2012, 03:56:06 am
Well (to paraphrase myself) that worked, TWICE!

Yup, it was the laptop closing the port. I don't blame the Eee PC1000H itself, it probably just needs a fresh install of the OS. Dunno why, but I'm using a different computer now (also XP SP3) and everything's running like butter wouldn't melt.

Sincere thanks for all the suggestions which have helped to stabilise my electronics and tighten my coding.

Thank you!

[RESOLVED] Near-enough smiley-wink
4  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 10, 2012, 10:59:12 am
@ billroy - Interesting idea, I'll stick it on my 'to do' list.

For now, I'm trying something I should've years ago and running my original serial-based setup from a completely different machine. I've been using a little EeePC up to now, which is beautifully compact, but had so much added/subtracted/plugged/unplugged over the years I can't help feeling there's something up with its USB ports. I've recently restored an old Acer Aspire 1350, so we'll see how that fares.

5  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 10, 2012, 07:17:06 am
Okay, here's what happened with all commands internalised and just 'OK' sent out from the Arduino after each command/scanline. Here's the output from Comport Toolkit, so I can't even blame VB any more  smiley-wink

15:07:1200:00:00Start of Job
19:51:1604:44:04Last 'OK' received (1089th)
11:48:5520:41:43End of job

After the 'OK's stopped appearing, the Tx light no longer flashed for the rest of the job. But the Serial.println("OK"); command must've been parsed by the Arduino as it was in the main loop. So, what's happening here?

Oh, and something else that's interesting is the fact that without the Serial exchange between the two machines it cut nearly 4 hours off the job!
6  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 09, 2012, 08:54:36 am
@dc42 - Yeah, I like the sound of that.

@billroy - Earlier I was losing the 'OK' after a single command was received and executed, which stalled the job. Without serial, all 7000+ commands are executed and the job finishes.
7  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 09, 2012, 08:07:48 am
Okay, here's a game-changer...

Out of sheer desperation I hard-coded all my serial commands into the Arduino sketch itself and removed all references to the serial bus. Still had the laptop connected, but only as a power source. The commands are quite repetitive for the first job I want to do, so it just took a couple of nested loops to replicate them exactly. Started it off yesterday lunchtime with exerything connected as normal, and a few minutes ago it finished, parked-up and powered-down.


So, can we assume it is the serial after all? I might try another run now with just Serial.begin() in the startup, to see if that works too.

Note: Just tried to upload new code, and the Arduino IDE halted with Serial Port 'COM7' already in use. Could this be a clue?
8  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 07, 2012, 02:54:01 pm
Interesting is one word! smiley-mad

Serial.print() everywhere sounds like a good plan right now, and it allows me to procrastinate further in the knowledge that I really need to rebuild my electronics from scratch. I'm a neat, careful worker, but the stripboard has been modified a few times since the original design, and I must've made a mistake somewhere. While building the machine I learned how to make custom boards anyway, hopefully something will show up soon before I get to that stage. Next time I fancy either using custom drivers (Allegro A4988) or Darlington arrays fed from a pair of 74HC595s to keep my pin-count low and allow me half-wave control instead of the klutzy two-wire config I'm using now. I'm also tempted to use opto-isolators between the Arduino and the control board, though I'm sure that's just overkill, an no-one would ever bother?

Without the servo control board connected to the Arduino the code runs fine, which suggests it's a hardware problem.

When everything's connected it works for anything up to 15 hours, then stalls between commands, which suggests it's a software problem.



Your analysis of the HardwareSerial code is a little beyond my comprehension I'm afraid, but I have a pin free so I'll try your suggestion in a day or so. Thank you.
9  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 07, 2012, 05:02:23 am
Ah, now THIS is why I went investigating the Serial port in the first place...

No it doesn't!

The Arduino receives the instruction, parses it, bounces it back to the VB's logfile, carries out the command and then just sits there. What happens internally at this point is still a mystery as the port is locked at this point, and the USB has to be physically un/replugged to restore it. On the other thread I even went to the extent of filming the Tx/Rx lights, but this proved fruitless as the Tx will not flash anyway if the port is locked by the laptop. I quit this line of investigation when I found that the code would run continuously without any attachment to the Arduino other than the USB. Here's my other thread, just for a different angle on the problem.,129286.0.html

10  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 06, 2012, 08:03:13 pm

I've tweaked the code so index won't overrun, and put a 10k pull-up on the reset. Still not working for more than a few hours.

const unsigned int maxIn = 50;
char inStr[maxIn];              // More than enough for longest command

void serialEvent(){
  while (Serial.available())
    char inByte = ();
    switch (inByte)
    case '\n':            // end of command
      inStr [index] = 0;  // terminating null
      stringComplete = true;
      index = 0; 
    case '\r':            // discard CR
      if (index < (maxIn - 1))
        inStr [index++] = inByte;

The thing that still bugs me is that the machine only ever stops AFTER carrying out a command. It gets it from VB, parses it, sends it back for logging, carries it out completely and only THEN freezes. I would've thought that if there were a problem with the wiring it'd just stall at any time, rather than neatly between commands.

I've wasted weeks blaming the serial, and the code, the OS (XPsp3) even the USB drivers themselves. Perhaps I need to put a loop of commands into the Arduino code and run it without using the serial and see if that manages to stay running?

11  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 03, 2012, 09:37:22 am
Okay, despite this code having run for three and a half days without issue (when only connected to the USB, anyway smiley-cry)...

What would be the best approach? Add a conditional to check each byte is good before adding it to the array?
12  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 03, 2012, 06:09:32 am
void xyzServos() {
  if (zSteps > 0 || (xSteps + y1Steps) < 500) tMult = 2000; // Change acceleration profile to suit Z(B)
  else tMult = 1000;            // stepper motor which stalls below 3ms
  max1 = max(xSteps, y1Steps);
  max2 = max(y1Steps, zSteps);
  totalSteps = max(max1, max2);
  mx = (double)xSteps/(double)totalSteps;
  my1 = (double)y1Steps/(double)totalSteps;
  my2 = (double)y2Steps/(double)totalSteps;
  mz = (double)zSteps/(double)totalSteps;
  x = mx;
  y1 = my1;
  y2 = my2;
  z = mz;
  laserOn = false;
  if (cut > 0 || laserTime > 0) {
    IOX.write(0x0200, OUTPORT); // Turn lamp & fan ON
    lampState = 0x0200;
  if (cut == 0 && laserTime > 0) digitalWrite(lpower, HIGH);
  for (int i = 0; i < totalSteps; i++) {
    x += mx;
    if (x >= 1 && mx != 0 && xStop == false){ // X-stepper control
      x -= 1.0;
      if (xDir == true) {
        if (xStepIdx == 0) xStepIdx = 4;
      else {
        if (xStepIdx > 3) xStepIdx = 0;
      if(twoWire[xStepIdx] & 1<<1){
      else {
      if(twoWire[xStepIdx] & 1<<0){
      else {
    y1 += my1;
    if (y1 >= 1 && my1 != 0 && yStop == false){ // Y1(South)-stepper control
      y1 -= 1.0;
      if (yDir == true) {
        if (y1StepIdx == 0) y1StepIdx = 4;
      else {
        if (y1StepIdx > 3) y1StepIdx = 0;
      if(twoWire[y1StepIdx] & 1<<1){
      else {
      if(twoWire[y1StepIdx] & 1<<0){
      else {
    y2 += my2;
    if (y2 >= 1 && my2 != 0 && yStop == false){ // Y2(North)-stepper control
      y2 -= 1.0;
      if (yDir == true) {
        if (y2StepIdx == 0) y2StepIdx = 4;
      else {
        if (y2StepIdx > 3) y2StepIdx = 0;
      if(twoWire[y2StepIdx] & 1<<1){
      else {
      if(twoWire[y2StepIdx] & 1<<0){
      else {
    z += mz;
    if (z >= 1 && mz != 0){ // Z(B)-stepper control
      z -= 1.0;
      if (zDir == true) {
        if (zStepIdx == 0) zStepIdx = 4;
      else {
        if (zStepIdx > 3) zStepIdx = 0;
      IOX.write(fullWaveB[zStepIdx] + lampState, OUTPORT);
    if (cut > 0) { // Put lasing code here..
      bitIndex = (i - (offset1 + space)) % (space + cut + space + gap - 1); // - 1 makes interval agree with vb HorizSteps value!
      if (bitIndex == 0 && i < (totalSteps - offset2)) laserOn = true;
      if (bitIndex == cut) laserOn = false;
      if (laserOn == true) {
        digitalWrite(lpower, HIGH); //rem-out while testing
      else {
        digitalWrite(lpower, LOW);
        delay(3); // fastest stable transit to next cutting point
    else {
      if (i < totalSteps / 2)
        iTimeIdx = i;
        iTimeIdx = totalSteps - i;
      if (iTimeIdx > 180) iTimeIdx = 180;
      MsDelay = (tMult*(3-(sin((270+iTimeIdx)*PI/180)))) - 1000;
      if (laserTime == 0) delayMicroseconds(MsDelay);
      else delay(laserTime);
    if (digitalRead(xsensors) == HIGH && i > 25) xStop = true;
    if (digitalRead(ysensors) == HIGH && i > 25) yStop = true;
    if (xStop == true || yStop == true) digitalWrite(lpower, LOW); // cut laser power if any limit reached
    if (xStop == true && yStop == true) i = totalSteps;            // bomb-out of loop if both limits reached
  digitalWrite(lpower, LOW);
  //IOX.write(0x0000, OUTPORT); // Turn lamp & fan OFF
13  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 03, 2012, 06:09:05 am
All chips have decoupling caps, and I've put a 22uF across the 5v. Test failed after 3hrs 24m...

So, here's my code, though I'm sure it's okay (I'll put the xyzservos handler in the next post)

// MMM_matrix_Plotter3a (pairs with MP3 New VB)
// tjn 20/11/2012
// Status: Interleaves X, Y1, Y2 and Z(B)
// Note: 78 Steps/mm using B servo in Full-wave mode, slack = 36

#include <Wire.h>
#include <iox.h>

// Setup pins (0 and 1 reserved for serial I/O)
byte xctrl1 = 2;                // X-Axis geartrain control 1
byte xctrl2 = 3;                // X-Axis geartrain control 2
byte yctrl1 = 4;                // South-Y geartrain control 1
byte yctrl2 = 5;                // South-Y geartrain control 2
byte y2ctrl1 = 7;               // North-Y geartrain control 1
byte y2ctrl2 = 8;               // North-Y geartrain control 2
byte tpower = 9;                // Trolley stepper supply
byte tctrl1 = 10;               // Trolley control 1
byte tctrl2 = 11;               // Trolley control 2
byte xypower = 12;              // XY stepper supply
byte lpower = 13;               // Laser logic supply
byte xsensors = 15;             // X-buffer switches
byte ysensors = 14;             // Y-buffer switches
byte scaleFactor = 1;
byte offset1, offset2, space, cut, gap;
byte xStepIdx, y1StepIdx, y2StepIdx, zStepIdx;
int xSteps, y1Steps, y2Steps, zSteps, totalSteps, subSteps, bitIndex, laserTime, tMult;
int xStore, yStore, zStore, pixCount, iterations, dotCount, max1, max2, iTimeIdx = 0;
char inStr[40];                 // Hold incoming data
byte index = 0;
boolean stringComplete = false; // Data complete flag
boolean xStop = false;
boolean yStop = false;
boolean xDir = false;           // TRUE = Clockwise
boolean yDir = false;
boolean zDir = false;
boolean oxDir = false;
boolean oyDir = false;
boolean ozDir = false;
boolean laserOn = false;
long MsDelay;
unsigned char twoWire[] = {
  B01,B11,B10,B00};             // 2-Wire sequence for X/Y steppers
word fullWaveB[] = {            // Full-wave Slave stepper motor sequence
word lampState = 0x0000;
double m, mx, my1, my2, mz, x, y1, y2, z;

void setup() {
  Serial.begin(38400);         // was 38400
  pinMode(xctrl1, OUTPUT);    // X stepper pin1
  pinMode(xctrl2, OUTPUT);    // X stepper pin2
  pinMode(yctrl1, OUTPUT);    // Y1 stepper pin1
  pinMode(yctrl2, OUTPUT);    // Y1 stepper pin2
  pinMode(y2ctrl1, OUTPUT);   // Y2 stepper pin1
  pinMode(y2ctrl2, OUTPUT);   // Y2 stepper pin2
  pinMode(tctrl1, OUTPUT);    // Trolley pin1
  pinMode(tctrl2, OUTPUT);    // Trolley pin2
  pinMode(lpower, OUTPUT);    // Laser power
  pinMode(xypower, OUTPUT);   // XY stepper power
  pinMode(tpower, OUTPUT);    // Trolley power
  pinMode(xsensors, INPUT);   // X-buffer switches
  pinMode(ysensors, INPUT);   // Y-buffer switches
  digitalWrite(xypower, LOW); // Power-down XY motors
  digitalWrite(lpower,LOW);   // Power-down laser
  digitalWrite(tpower,LOW);   // Power-down trolley
  Wire.begin();               // Start 2-wire communications (Arduino as master device)
  IOX.device(0x74, 16);       // 0x74 is address for Servo A (Pitch)
  IOX.write(0x0080, CFGPORT); // P07=INPUT Set ports LOW to make them OUTPUTS
  IOX.write(0x0000, INVPORT); // Set slave device invert ports to all NON-INVERT
  IOX.write(0x000, OUTPORT);  // Power-down Lamp/Fan

void loop() {
  if (stringComplete) {
    xSteps = atoi(strtok(inStr, "xy"));   // X Transit
    y1Steps = atoi(strtok(NULL, "z"));    // Y Transit
    zSteps = atoi(strtok(NULL, "l"));     // Z Transit
    laserTime = atoi(strtok(NULL, ",o")); // Laser On/Off
    offset1 = atoi(strtok(NULL, "s"));    // Offset1
    space = atoi(strtok(NULL, "c"));      // Space
    cut = atoi(strtok(NULL, "g"));        // Cut
    gap = atoi(strtok(NULL, "i"));        // Gap
    iterations = atoi(strtok(NULL, "o")); // Iterations
    offset2 = atoi(strtok(NULL, ""));     // Offset2

    if (xSteps < 0) xDir = true;
    if (xSteps > 0) xDir = false;
    if (xSteps == 0) xDir = oxDir;
    if (y1Steps < 0) yDir = true;
    if (y1Steps > 0) yDir = false;
    if (y1Steps == 0) yDir = oyDir;
    if (zSteps < 0) zDir = false;
    if (zSteps > 0) zDir = true;
    if (zSteps == 0) zDir = ozDir;
    if (xStop = true && xDir != oxDir) xStop = false;
    if (yStop = true && yDir != oyDir) yStop = false;
    xSteps = abs(xSteps);
    y1Steps = abs(y1Steps);
    zSteps = abs(zSteps);
    y2Steps = y1Steps;

    if (zDir != ozDir) { // Vertical Slack Handler
      zSteps += 37;      // Z-Slack value (from laser deflection test)

    totalSteps = max(xSteps, y1Steps);
    subSteps = min(xSteps, y1Steps);
    m = (double)subSteps/(double)totalSteps;

    if (m > 0.7) { // vector splitter/dog-legger to dodge bad harmonics
      if (xSteps > y1Steps) {
        xStore = xSteps;
        yStore = y1Steps;
        xSteps = xStore - y1Steps;
        y1Steps = 0;
        y2Steps = 0;
        digitalWrite(xypower, HIGH);
        xSteps = yStore;
        y1Steps = yStore;
        y2Steps = y1Steps;
      if (xSteps < y1Steps) {
        xStore = xSteps;
        yStore = y1Steps;
        y1Steps = yStore - xSteps;
        xSteps = 0;
        digitalWrite(xypower, HIGH);
        xSteps = xStore;
        y1Steps = xStore;
        y2Steps = y1Steps;
      // else not used (no adjustment needed when X & Y are equal! 

    if (xSteps != 0 || y1Steps != 0 || zSteps != 0) {
      digitalWrite(xypower, HIGH);
      xyzServos(); // rem-out while testing
    else {
      if (laserTime == 1) {
        digitalWrite(lpower, HIGH); // Laser ON
        IOX.write(0x0200, OUTPORT); // Lamp & Fan ON
        digitalWrite(lpower,LOW);   // Laser OFF
        IOX.write(0x000, OUTPORT);  // Lamp & Fan OFF

    if (xSteps  == 0 && y1Steps == 0) { // switch OFF motors on end vector
      //digitalWrite(xypower, LOW);     // Machine loses registration on power-down!
      if (laserTime == 0) IOX.write(0x0000, OUTPORT); // Turn lamp & fan OFF

    if (xStop == true) Serial.println("X-buffer Hit");
    if (yStop == true) Serial.println("Y-buffer Hit");
    Serial.println("OK"); // Tell VB Arduino's ready to receive next command from vb   
    stringComplete = false;
    oxDir = xDir;
    oyDir = yDir;
    ozDir = zDir;

void serialEvent()
  while (Serial.available())
    char inChar =;
    inStr[index++] = inChar;    // add to the inStr
    inStr[index] = '\0';        // NULL terminate the array
    if (inChar == '\n')
    {                           // Flag if char is vbcrlf
      stringComplete = true;
      index = 0;
14  Using Arduino / Motors, Mechanics, and Power / Re: Arduino Randomly Freezing During Long Jobs on: December 02, 2012, 11:43:51 am
Thanks for the suggestions!

I'd suspected that there wasn't enough smoothing going on, so last night I started a long test with a 470μF cap across the 5V/GND on the Arduino, which seemed to work better (ie. it stalled after nearly 15.5hrs).

@dc42 - I have no String class in my code, it works fine without my driver board attached and it's well within my available RAM. Thanks for asking.

I understand the comments about motor transients, but I'm still a bit worried that a test I did earlier with only the driver board's 5V/GND connected to the Arduino still managed to fail after a few hours, despite the complete absence of switching loads and motor supplies. I just can't understand how that would happen, especially as there was no other power going to the board.

I will add caps to all my ICs today, and see if that helps...

15  Using Arduino / Motors, Mechanics, and Power / Arduino Randomly Freezing During Long Jobs on: December 01, 2012, 03:17:58 pm

I've built a 6-DOF micro pick 'n' place robot which I will use to assist me in the creation of various digital artworks. My problem is that the machine runs beautifully for many hours, but then freezes for some unknown reason. This stalling always happens after the previous command has been carried out cleanly, and can occur anywhere (according to my last 20+ logfiles) between 29 seconds and 15 hours into the job.

I originally blamed the VB serial port for this (I left a huge thread on the interfacing section of this forum), but after successfully running the code for over three days with just my Arduino UNO parsing instructions via USB from the laptop, I decided it must be an electronics problem. I designed my stepper board using LochMaster, which is great for quick prototyping, but doesn't produce a pretty schematic view so forgive this ugly graphic of my setup.

This is my first time building such a contraption, so I'm hoping that the cause of the freezing will be obvious to someone out there. My main X/Y supply is a 20v 4A Laptop supply, and the 7v for my tool module comes from a 1.3A switching wallwart. And before you tell me those supplies are squarely to blame, I can still get the machine to stall with both of them unplugged and just logic going into the board via the left-hand connector. Also, I took the precaution of disabling BOD on the ATmega328p, but it made no difference.

Thanks for your time,

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