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1  Using Arduino / General Electronics / Re: Laser detection, Transistor problem... on: February 09, 2014, 12:55:05 pm
Unfortunatly, after some test, Coax cable is better but the system remains unstable smiley-confuse

The Circuit is very sensitive, because I only have to touch the sheath of the cable to trigger the transistors.

what  I need to change to reduce this sensitivity?
Maybe the first capacitor of 10nF to 1μF to filter more?

Thank you
2  Using Arduino / General Electronics / Re: Laser detection, Transistor problem... on: February 08, 2014, 04:12:30 pm
I just test a Coax cable , no more problems .. Thank you!
You think a Cat.5 FTP network cable can also do the trick? Because I would put several photodiode in parallel.
3  Using Arduino / General Electronics / Re: Laser detection, Transistor problem... on: February 08, 2014, 03:46:58 pm
Try some different valued capacitors across the input ex. .001  etc.
Also consider adding some decoupling for the power supply.

I try 0-100K Ohm variable resistor nothing change..

FYI Voltage input is 12v, 4A. (Laser photodiode, support more than 40V)
4  Using Arduino / General Electronics / Re: Laser detection, Transistor problem... on: February 08, 2014, 03:44:12 pm
You need shielded coax cable to the diode, you are just picking up RFI.

[ well probably.  Another possibility is oscillation. ]

Indeed, it is quite logical explanation for coax ...  I will try tomorow . What do you mean with oscillation?

5  Using Arduino / General Electronics / Laser detection, Transistor problem... on: February 08, 2014, 03:26:40 pm
Hello all,

I have made this circuit (below) for laser detection in my work with photodiode in (X1-1 ; X1-2) and  Arduino. Everything works perfectly.

For technical reasons, I wish away the photodiode from the board (arround 1.5 m). But when I put a cable (02x0.4mm) greater than 30 cm between the photodiode and the board , transistors engage, as if there were laser detection.
I try to put variable resistors between the first transistor, but it has nothing do ...

any help would be welcome, as I am completely stuck

Br smiley-wink
6  Using Arduino / LEDs and Multiplexing / Re: Laser pulse counting on: January 12, 2014, 12:09:34 pm
Quote
how to measure pulse?

First you have to define what properties of the pulse you wish to 'measure'. Is it pulse width, pulse repetition rate, Pulse high voltage value, pulse low voltage value?
I had assumed pps.

Quote
As I see, maybe i am wrong,  to use comparator you need to have  02 hard source to compare, or here I have diode and light smiley-confuse
You setup the comparator circuit so laser off reading from your circuit falls below trigger threshold and laser on pushes your comparator circuit reading above the threshold. The comparator output would trigger a interrupt on a digital pin that increments a counter. In your program loop you zero this counter, wait 1 second and read the counter to get how many pulses have happened. What you do with this result if it's not what youe expected is up to you.


Thank you for that clarification.

This code is correct ?

Code:

volatile boolean triggered;
int counter = 0;

ISR (ANALOG_COMP_vect)
  {
  triggered = true;
  }

void setup ()
  {
  Serial.begin (115200);
  Serial.println ("Started.");
  ADCSRB = 0;           // (Disable) ACME: Analog Comparator Multiplexer Enable
  ACSR =  _BV (ACI)     // (Clear) Analog Comparator Interrupt Flag
        | _BV (ACIE)    // Analog Comparator Interrupt Enable
        | _BV (ACIS1);  // ACIS1, ACIS0: Analog Comparator Interrupt Mode Select (trigger on falling edge)
   }  // end of setup

void loop ()
  {
  if (triggered)
    {
  counter++;
    }
  delay(1000);
  if (counter==100)
    {
    Serial.println ("Laser is ok at 100 pps.");
    }
   else
    {
    Serial.println ("Laser is not ok!!");
    }
  counter=0;
  }  // end of loop
7  Using Arduino / LEDs and Multiplexing / Re: Laser pulse counting on: January 12, 2014, 11:57:52 am
What I do know is that this is a stream of pulses at 900nm.
8  Using Arduino / LEDs and Multiplexing / Re: Laser pulse counting on: January 12, 2014, 11:44:52 am
Have a look at this for how to use the UNO's analogue comparator or maybe use an external one.  

As I see, maybe i am wrong,  to use comparator you need to have  02 hard source to compare, or here I have diode and light smiley-confuse

I found this picture in the net:
 can I do same with android?

thank's
9  Using Arduino / LEDs and Multiplexing / Laser pulse counting on: January 12, 2014, 10:56:27 am
Hi all,

I have to make an arduino program to check the proper functioning of an infrared laser (900nm) that pulse exactly to 100 pps.
I will use a diode SFH203FA like this circuit:


how to measure pulse?
I have put several diodes to refine the results?

The response of the arduino should be fast because it must stop a production line quickly if bad value.

I'm still a beginner, thank you for helping me on for the code .

Br,


10  International / Français / Re: Carte Arduino maison, aide routes avec Eagle ? on: January 27, 2013, 04:18:03 am
Salut,

800x600! il faut passer à l'aire du numérique et changer d’écran mon ami!

Je n'ai pas réussi à appliquer tes conseils, par contre j'ai ajouté des "pad" manuellement avec je relierais les lien des composants par un fil au dessus de la carte.

en pièce jointe la motif pour ceux  qui voudrais faire la même chose.

A+
11  International / Français / Carte Arduino maison, aide routes avec Eagle ? on: January 27, 2013, 02:50:30 am
Bonjour,

Je vais réaliser une carte arduino maison, qui va me permettre  en plus des classique I/O de controler directement 3 relais (5v/220v) et deux moteurs électrique avec un chip L293D.

Je souhaiterais qu'un pro y jette un coup d'oeil pour me prévenir des éventuelles erreurs smiley

Mon problème est que je n'arrive pas a router correctement les liaisons avec Eagle,  en fait je ne possède que des plaques ne cuivre simple face et je voudrais router le maximum de fils sur le dessous et  pour les liaisons qui ne sont pas possible, qu'il m'indique ou percer pour faire des pont avec des fils de cuivre sur le dessus de la carte.
Est ce possible?

Si vous avez d'autres idées pour le placements des composants, sa serait sympa aussi!

Merci
12  Using Arduino / Project Guidance / Laser 3D printing Stereolithography using galvo on: January 24, 2013, 02:47:33 am
Hello,

I intend to build a 3D Laser printing inspiration from the excellent tutorial : http://www.instructables.com/id/Build-a-Laser-3D-Printer-Stereolithography-at-Ho/
But I would make some changes to have a printer at less than 150 euros!

1 / instead of using mechanical parts for the X-axis and Y- axis i would une galvo,  on Ebay there are less than $ 80 : http://cgi.ebay.fr/HighSpeed-Plug-PlayGalvo-Scanning-System-w-h-ILDA-Show-Card-15Kpps-20Kmax--/251179487993?pt=LH_DefaultDomain_0&hash=item3a7b76d2f9#ht_1603wt_1157

2 / for the Z axis, a simple servo enough I think?

What do you think?
It is difficult to control a galvo with arduino?

thank you
13  International / Français / Imprimante Laser 3D via galvo on: January 24, 2013, 02:38:50 am
Bonjour,

Je compte me construire un imprimant Laser 3D en m'inspirant de l'excellent tuto http://www.instructables.com/id/Build-a-Laser-3D-Printer-Stereolithography-at-Ho/
Par contre je voudrais apporter quelques modification pour avoir une imprimante à moins de 150 euros!

1/ en utilisant la place des pièces mecaniques pour l'axe des X et Y,  un galvo ,  sur Ebay il y en à moins 80$ de http://cgi.ebay.fr/HighSpeed-Plug-PlayGalvo-Scanning-System-w-h-ILDA-Show-Card-15Kpps-20Kmax--/251179487993?pt=LH_DefaultDomain_0&hash=item3a7b76d2f9#ht_1603wt_1157

2/pour le Z un simple servo sufira je pense?

Vous en pensez quoi?
Il est difficile de controler un galvo avec une arduino?

Merci
14  Using Arduino / Sensors / Re: Sensor value calculation on: December 30, 2012, 09:58:58 am
Thank 's all for your reply.

Japanese guys seems drive it to work : http://translate.google.tn/translate?sl=auto&tl=en&js=n&prev=_t&hl=fr&ie=UTF-8&eotf=1&u=http%3A%2F%2Ftomono.eleho.net%2F2011%2F03%2F08%2F761%2F&act=url

We cannot calculte the value with is graph :http://einstlab.web.fc2.com/hum/HS15P.png?

Currently in my country it is about 70% humidity
the value received by the analog input is from 1060 to 70% of humidity.
When I made ​​the mist on the sensor is at 1090-1100.

It's that simple? I remove  1000 and I have good values? smiley
15  Using Arduino / Sensors / Re: Sensor value calculation on: December 30, 2012, 09:37:41 am
Hi,

here the hole script, with lm35 T° sensor and HS15p .

The problem that this script is not made for HS15P but similar Humidity sensor with 2 pins.

Code:
int TemPin = 0; // analog pin
int HumPin = 1; // humidity
int tempc = 0, // temperature variables
int samples[8]; // variables to make a better precision
int maxi = -100,mini = 100; // to start max/min temperature
int i;

float humi = 0;
float prehum = 0;
float humconst = 0;
float truehum = 0;
float pretruehum = 0;
long pretruehumconst = 0;
long valb = 0;

void setup()
{
Serial.begin(9600); // start serial communication
}

void loop()
{

for(i = 0;i<=7;i++){

samples[i] = ( 5.0 * analogRead(TemPin) * 100.0) / 1024.0;
tempc = tempc + samples[i];
delay(1000);
}

tempc = tempc/8.0;
tempf = (tempc * 9)/ 5 + 32;

valb = analogRead(HumPin); // humidity calculation
prehum = (valb);
humconst = (0.16/0.0062);
humi = prehum - humconst;
pretruehumconst = 0.00216*tempc;
pretruehum = 1.0546-pretruehumconst;
truehum = humi/pretruehum ;
delay(1000);

Serial.print(tempc,DEC);
Serial.print(" Celsius, ");
Serial.print ("Humidity: ");
Serial.print ((long)truehum);
Serial.println ("% ");

tempc = 0;

delay(1000); // delay before loop
}

Moderator edit: Quote swapped for code tags
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