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166  Community / Bar Sport / Re: Saving my Diecimila EEPROM on: February 05, 2014, 02:31:32 pm
Yep, Jack. You are right. I was wrong. I'm talking about a Diecimila. I didn't have a good view of the board, thus I assumed it. The thing is that the technician that wrote the code is not with us anymore and there is no way to retrieve the program info. I think is a new ongoing project for me to starts with but using may be a UNO R3 like you recommend or a DUE. thanks.
167  Community / Bar Sport / Saving my Diecimila EEPROM on: February 05, 2014, 01:03:18 pm
After almost eight (smiley-cool years, I think I am close to exhaust the life of the 512B EEPROM of my Arduino UNO Rev 1 which is part of a 24/7 non-stopping printing system. One of its functions in the system is the storage (log) data of all of the printed pages (~200 cycles/day). A couple of years ago, during a TAM, I extended part of its life by using the 'wear leveling' technique but I believe that the EEPROM- which I have called "sehr-alt-um"- it has only few more months to live. Recently and after various complains, I succeeded in getting a bigger air conditioning unit in the room to lower the temperature (I've learned that the EEPROM failure rate can be dramatically reduced if the operating temperature is reduced and and therefore it extends my EEPROM endurance). Is there something I can do to extend its life 'a bit more' before the beginning of failing or corrupting our printing data? -P.
168  Using Arduino / General Electronics / Re: Getting a better shape for 500kHz square pulses on: February 03, 2014, 11:28:38 am
As promises are made to keep, here some tests you requested in my UNO-LED-R pulses in order to get shaped square pulses.

With LED disconnected, that is, scope probe direct to P9: I got a shaped square signal! See picture #2.

With finger on the LED before remove it: the original shape doesn't change.

Shorting the LED: Same as picture #2.
Using 220 ohm. Same as picture #2.

With 1N4004 across the 10K resistor, anode to ground: I got a shaped square signal with LOW period >0. See picture #3.

I am not measuring dynamic changes in Vf. Just mentioned Nisley comment.

-The tail was created by the LED.

I should like to thank everyone who has contributed to this brief review. Palliser.
169  Using Arduino / General Electronics / Re: Getting a better shape for 500kHz square pulses on: February 01, 2014, 08:40:38 pm
Why the wave shape? I'd say for aesthetic reasons, or may be to reconcile theory and practice? Over 30 years ago, trying to obtain a 500kHz pulse train from a VCO (4046), I was only able to get an almost sinusoidal signal.  smiley-eek-blue.
In his article 'Pulsed LED Characterization', Ed Nisley in Circuit Cellar #280 (Nov.2013) states,

...the exponential drop in forward voltage during the pulses shows the effect of junction temperature.

 Is he right? I will discover that on Monday.
170  Using Arduino / General Electronics / Re: Getting a better shape for 500kHz square pulses on: February 01, 2014, 09:17:38 am
You are right regarding the LED connection.
My schematic:

I'll do the finger test on Monday and let you know.

171  Using Arduino / General Electronics / Re: Getting a better shape for 500kHz square pulses on: January 31, 2014, 11:37:38 pm
Thank you jiggy-Ninja for your comments. I had the LED and resistor from a prior project. I'll be far from my office (and scope) this weekend but hoping to confirm your note on Monday. Regards!
172  Using Arduino / General Electronics / Re: Getting a better shape for 500kHz square pulses on: January 31, 2014, 10:48:51 pm
I am driving a LED (red) in series with a 10K resistor.  I haven't detailed the 10x probe of the scope.
173  Using Arduino / General Electronics / Getting a better shape for 500kHz square pulses on: January 31, 2014, 10:19:38 pm
Hello. I tested a sketch taken from section 18.4 of the book 'Arduino Cookbook' by Michael Margolis.
See Page 612->

The sketch generates pulses within the frequency range of 1 MHz to 1 Hz using Timer1 PWM on pin 9. I tested it with Arduino UNO for 500kHz.

A picture of the pulses:

I used the TimerOne library (.cpp,.h) from:

The sketch:
#include <TimerOne.h>
#define pwmRegister OCR1A // the logical pin, can be set to OCR1B
const int outPin = 9; // the physical pin
long period = 2; // the period in microseconds
float pulseWidth = 1; // width of a pulse in microseconds
int prescale[] = {0,1,8,64,256,1024}; // the range of prescale values
void setup()
pinMode(outPin, OUTPUT);
Timer1.initialize(period); // initialize timer1, 1000 microseconds
void loop()
bool setPulseWidth(long microseconds)
bool ret = false;
int prescaleValue = prescale[Timer1.clockSelectBits];
// calculate time per counter tick in nanoseconds
long precision = (F_CPU / 128000) * prescaleValue ;
period = precision * ICR1 / 1000; // period in microseconds
if( microseconds < period)
int duty = map(microseconds, 0,period, 0,1024);
if( duty < 1)
duty = 1;
if(microseconds > 0 && duty < RESOLUTION)
Timer1.pwm(outPin, duty);
ret = true;
return ret;

I'm not sure but the shape of the square pulses could be product of internal RC circuit and do raises the question of whether is possible or not to shape up of the pulses using external electronic devices like 7414 Schmitt trigger or other to obtain cleaner pulses. Regards!
174  Products / Arduino Due / Re: Building a CAN API for Arduino DUE on: January 21, 2014, 09:54:23 am
Nice product! Thank you Dan for your contribution to make the Arduino DUE CAN interface easy to access using your protoshield. Please, keep us posted about the feedback from your curstomers. Regards, Palliser.
175  Products / Arduino Due / Re: Arduino Due and Ethernet Shield R3 -- Please help! on: December 10, 2013, 09:44:04 am
Hello Kevin,
Could you try the code in the following thread? (Reply # 7)

It worked for me. You could use it to verify your system. Regards!
176  International / EspaƱol / Re: Conectar un chip on: December 05, 2013, 12:21:53 pm
Hola charlesblack,

Yo tengo una tarjeta con el mismo chip (MPU-6050) pero diferente fabricante (CSG) y adicionalmente tuve que conectar a tierra (GND) los pines FSYNC, CLK y AD0 (direccion I2C 0x68) para que me funcionara. Tambien para correr el ejemplo MPU6050_DMP6 necesitaras conectar el pin INT del chip al pin D2 del Arduino dado que este ejemplo utiliza la interrupcion 0 del Arduino. 
El ejemplo que te menciono (MPU6050_DMP6) es mas sofisticado que el otro (MPU6050_raw) ya que usa computos directos del procesador 6050. Suerte y saludos cordiales.

177  Products / Arduino Due / Re: audio in due on: December 05, 2013, 11:45:24 am
Hello m_lab85,

The tutorial makes reference to the TL0xx (see step 3). Those opamps do not have GND pin but Vcc-.

Thus, I believe the GND in the OP-AMP symbol of Amanda's schematics should be Vcc-.

Also, there are two 9V batteries connected in series to power the OP-AMP.
- The positive of the top battery supplies +9V and is your +Vcc for the opamp.
- The negative of the bottom battery has -9V and is your -Vcc for the opamp.
- The negative of the top battery (or the positive of the bottom battery) is your OV reference (float ground) for the Arduino.

I hope this helps. Regards!
178  Products / Arduino Due / Re: Unable to use Ethernet and SD at the same time on DUE, but on UNO it works fine on: December 05, 2013, 11:06:16 am
Hello nakedsensor,
UNO and DUE have different micro-controllers (AVR and SAM3X), thus, internally they work also differentlyand use different libraries. Please, look at the following thread.

There, in my reply #7 you will find a code that works OK for a DUE and an Ethernet shield. Good luck!
179  Products / Arduino Due / Re: Connecting an Ethernet PHY to Arduino Due on: December 03, 2013, 04:25:13 pm
Hi Tony,
I am very happy and surprised with your Duet. Also anxious to watch the video. It reassures me that every grain of sand distilled from the forum can inspire people like you. I take my hat off to you guys. Best regard! Palliser
180  Using Arduino / Sensors / Re: yaw stability on: November 30, 2013, 10:32:35 am
Hello dr_no,
Are you using the Arduino library or another one like Jeff Rowberg's?
Jeff'DMP, once detects the yaw values as drift rather than movement, it decreases the jaw value for abour 20-30 sec before stabilize (normally from 30 to zero). Remember that jaw from gyros will always drift. If you want a stable jaw you will need a magnetometer but then you will have to deal with magnetic external interference. Regards!
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