LED sensing question

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello

It's my first post here and i'm sorry for some noob questions

Anyway, i'm trying to build this LED sensing stuff as described in Playground "LEDsensor" page and everything worked fine when i used a breadboard and wires.
When i made a simple small one-layer pcb with a connector and led everything stopped working.
Is that a problem with pcb track capacity? can it be solved easily or should i better switch to another scheme (maybe a code with analog pin involved or interfacing a ready built sensor)?

Thanks a lot in advance

2

Pictures and schematics would be most helpful in seeing what your problem is.

3

yes, forgot to do that, sorry

the pcb is extremely simple but it doesn't work if compared to 2 LED plugged into wires directly.

Thanks in advance.

4

yes, it's really strange.

i've got an arduino nano (3.0) plugged into a breadboard. when i simply plug wires (about 10cm) into breadboard and connect two leds to them - the wjole thing works great. When i plug wires in this "board" instead of just LEDs - the led between that 2 & 3 pins constanty lits as if it gets LOW value in that "if (j<30000)" loop in the code...

5

Sorry for my messy explanation and thanks for answering.

I'm using the code from the example that applies the reversed voltage to led through arduino pins 2 and 3. 2 is cathode and 3 is anode. then i connect that two arduino pins to one of the leds on the board and connect a +5V dc through a 100 Ohm resistor on a breadboard to another LED. no matter which led i use for sensing i get just two leds constantly lit.