6V to LED, 3V output...no light?

Hey all.

I'm creating my own Arduino on a breadboard using this tutorial (Arduino - Setting up an Arduino on a breadboard).

It all works fine. Power light works, getting correct voltage throughout the chip and at the input to the Pin 13 LED (6V for 1 second, then 0V for 1 second repeated.)

But the LED doesn't illuminate. I thought it might be a blown LED or resistor, but exchanging them with the power items still doesn't fix it (and they work in the other positions).

Any ideas? It seems to be getting the correct voltage for the correct times, but doesn't actually illuminate...

Confusing description. Which LED does not work, the power led or the pin 13 led?

You do realize that LEDs only work one way around?

Test each led+series resistor between 5V and GND. Its not impossible that a led has been incorrectly manufactured and the "flat" is next to the anode instead of next to the cathode.

Also, when you said "6V" was that a typo? Should be 5V. Anything over 5.5V could damage the chip.

The Pin13 LED doesn't work. The power LED does.

I've replaced both LEDs and resistors to no effect. They have all been confirmed as working. I also do get a ~3V drop across the pin13 LED as expected.

It's definitely 6V. Maybe I'll have a check and see why I'm getting that...

Fingers crossed I haven't fried the microprocessor...

Once you have corrected the supply voltage issue, try another pin for the led. Maybe you blew pin 13.

Ok, might have been my mess up (100% sure it is...)

So instead of having my 9V battery attached to one of the 10uf docoupler capacitors..I had it going directly into the 5V / Grnd lines at the top (I usually have an adaptor fitted, I left it fitted purely through habit.)

I'm not sure what I've blown. The chip is fine - I've swapped it out with the one in my arduino and it runs fine from mulitple pins. The one I swapped out with doesn't run anything on my breadboard but when swapped around again works perfectly.

I've had a quick check of everything I can think of. Switched out the oscillators, voltage regulators, capacitors....nothing has fixed it.

I'm at a complete loss. It's got to be wired up wrong somewhere? Can anyone spot anything incorrect?

For some reason I can't add attachments? So here is a link to the image

So instead of having my 9V battery attached to one of the 10uf docoupler capacitors..I had it going directly into the 5V

The decoupling capacitor is irrelevant in this case. If you connect a 9V battery to the 5V pin you will fry the Arduino board.

For some reason I can't add attachments?

Then read How to use this forum and the image guide.

We don't like going off site for images, that site is spam ridden.

Grumpy_Mike:
The decoupling capacitor is irrelevant in this case. If you connect a 9V battery to the 5V pin you will fry the Arduino board.

I wasn't connected to an arduino board? This breadboard is supposed to run from a 9V battery. I had it going into the + line at the top of the breadboard.

Grumpy_Mike:
Then read How to use this forum and the image guide.

We don't like going off site for images, that site is spam ridden.

I've read the rules for posting images. I get an error saying "contact the forum administrator".

Thanks though.

Don't worry, I've fixed it.

It turned out to be a dodgy breadboard. I transferred everything to a known working one and it's working a treat.

Thanks for those that tried to help out!

Phoenix492:
This breadboard is supposed to run from a 9V battery. I had it going into the + line at the top of the breadboard.

The breadboard does not care what voltage you put through it (up to a point). Its not designed for any particular voltage. The AVR chip, on the other hand...

PaulRB:
The breadboard does not care what voltage you put through it (up to a point). Its not designed for any particular voltage. The AVR chip, on the other hand...

Yeah, I know. Someone who replied said that if I connected 9V to any 5V I would fry any arduino board. I was pointing out that I wasn't connected to any arduino board any way (and you can connect 9V to any arduino board) but connected to a breadboard, with a circuit designed to work from a 9V battery.

and you can connect 9V to any arduino board

Yes but only to the power jack and the Vin pin, not to the 5V pon.