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Topic: interfacing led matrix in live mode (Read 3549 times) previous topic - next topic

tomas

I understand from these posts that it is pretty easy to control the 8x8 matrix with the maxim chip.
so until the chip arrives from maxim..

I have a question - If I want to send the characters to the matrix LIVE , that means not send code and then disconnect arduino from the computer but have a small applet (visual c? flash?) that I can , for example type a letter into , and that letter would appear on the matrix display.

I understand we are dealing with the serialwrite() serialread().... but how to interface simply?

so - the problem is I know only visual C and basic , so I would need a few example programs if this has to be in other languages.
anyway pointers to example code would be GREATLY appreciated.

also a BIDIRECTIONAL LED MATRIX which can function as an input/output device has been demonstrated in make magazine and hackaday. (link soon) if anyone knows how to implement this in arduino it would be awesome! (even for 2-3 leds)

thanks
and keep up the good work
Tom

ccdust

#1
Jun 01, 2006, 12:45 pm Last Edit: Jun 01, 2006, 02:54 pm by ccdust Reason: 1
Quote
also a BIDIRECTIONAL LED MATRIX which can function as an input/output device has been demonstrated in make magazine and hackaday. (link soon) if anyone knows how to implement this in arduino it would be awesome! (even for 2-3 leds)


check my http://www.google.com/notebook/public/04067928292063431351/BDRwbSwoQhdb3s7Uh in reserch papers :)
this is what i get so far but nothing works
Code: [Select]
/* BILED
Janez Troha

Controling bi directional leds
*/

unsigned long val;
void setup(void) {
//Serial.begin(57600);
}

void loop(void) {
pinMode(2, OUTPUT); //anode
pinMode(3, OUTPUT); //cathode
digitalWrite(2, HIGH); //anode of led
digitalWrite(3, LOW); //cathode of led
delayMicroseconds(60);
digitalWrite(2, LOW); //anode of led
digitalWrite(3, HIGH); //cathode of led
pinMode(3, INPUT); //cathode
val =  pulseIn(3, HIGH);
//printInteger(val);
//printNewline();
//delay(100);
}


iam also thinking of use pulsein, but uc hangs when it comes to that, any thoughts?

tomas

#2
Jun 04, 2006, 12:51 pm Last Edit: Jun 04, 2006, 12:54 pm by tomas Reason: 1
check out

http://motestruments.com/led-touch-sensor-circuit/

is it possible in arduino - arduino can use same pin as input AND output.. ???

what if the same led is hooked up to 3 pins.. with another diode to analog in?

also alternating between 2 leds to get A lighting when B is sensing... to sense objects like fingers etc. not only ambient light

I will read your notebook further and think about it..

help please everyone!

ts



ccdust

:D :D :D :D
It works nowbut with analog in, the code:
Code: [Select]
/* BILED
Janez Troha

Controling bi directional leds
*/

int cajt;
void setup(void) {
//Serial.begin(57600);
}

void loop(void) {
pinMode(2, OUTPUT); //anode
pinMode(3, OUTPUT); //cathode
digitalWrite(2, HIGH); //anode of led
digitalWrite(3, LOW); //cathode of led
delay(1);
digitalWrite(2, LOW); //anode of led
digitalWrite(3, HIGH); //cathode of led
delay(10);
digitalWrite(3, LOW); //cathode of led
pinMode(3, INPUT); //cathode
cajt = analogRead(0);
if (cajt > 75)
{
pinMode(13, OUTPUT); //cathode
digitalWrite(13, HIGH); //anode of led
}
if (cajt < 74)
{
pinMode(13, OUTPUT); //cathode
digitalWrite(13, LOW); //anode of led
}
//Serial.println(cajt);
//delay(100);
}


but the led sensing is very unstable, but it works now, I am using red LED, 20mA!


tomas

ok ccdust , now please tell me how you did it:

how did you connect the led to 3 pins? simple split? 2nd diode?
is it a hi-power led? if not then maybe a hi-power will work better

maybe you have a photo of your setup?

are you sensing a flash light??? it will  not work best!! leds sense their own bandwidth best!
so the best setup is 1 led as a light source and second as sensor

anyway good job
ts

Benoît ROUSSEAU

Hello,

  I've made it for one LED with Arduino without any anlog input, take a look at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1146679536. Take care about pull-up.
Cordialement,
Benoît ROUSSEAU

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