Lesson 5 - Some are brighter than others?

[threebean]

Hi,

I just got done playing around with lesson 5 and changed it to have 10 LEDs. I am using pins 3 - 12 as outputs.

The thing is, some of the LEDs are dimmer than the others. It almost seems as though pin 3 is the brightest and pin 12 is the dimmest. Pins 9, 10, 11, 12 are noticeably dimmer than 3. I think the others are also dimmer, but they are not that different that it calls attention to them.

I have swapped the LEDs around and it doesn't matter. I have tried new resistors, and swapping them too. Same thing 3 brightest, 12 dimmest.

I thought it might be due to too many being on at once, but even when there is only 1 on at a time, the level of brightness is in correlation to it's pin position.

Any ideas?

I have pictures of the setup, but I will have to post another one to show the dimm effect.

Thanks for the tutorial - it was awesome! I am going to use this in my Halloween robot costume.

-Steven

[threebean]

OH,

I also want to give a HUGE THANK YOU to ladyada!

I really appreciate the time you took to write and publish the lessons/tutorials.

I was thinking of how I could use my Arduino for my costume control panel and I thought to check back with your site to see if any of your lessons could get me started. Lesson 5 was perfect!

THANKS AGAIN - you really made my day!!!

[adafruit]

pins 9, 10, 11 & 12 are used for serial programming. try using the analog input pins (they can be setup as outputs, just call them pins 14-20)

[threebean]

Cool, thanks for helping me out. I will give that a try tonight!

[threebean]

Hi,

I gave that a try last night, but got the same results. I am posting a picture of it.

Turns out that those 4 didn't matter, tho i would like to figure it out for my own knowing. I went to put it into the box and i didn't have room for 10 anyway, 6 is just perfect.

I will have to post a picture of it in the box and maybe a video of it if i can.

Thanks again for the help on my Halloween costume!

[westfw]

While 1k resistors are nice safe values for experiments, when you have "exotic" colored LEDs like you have (very pretty, BTW), you're severely UNDER-driving them. Assuming Vf of about 3.5V, you're only putting about 1.5mA through them (and presumably they're 20mA LEDs.) That MIGHT be a drive level where relatively minor changes in pin characteristics make significant differences in illumination. Try 100 to 220 ohms?

(I don't see brightness differences in the little chase circuit I've got going next to me, but I don't have any resistors in the red led paths, so I'm presumably overdriving the LEDs a lot...)

[trialex]

Also double check you have a

Code: Select all

pinMode(pin, OUTPUT);

for every pin - if you don't they can't source/sink as much current and LEDs are a lot dimmer.

[threebean]

trialex - you get a beer! That is exactly what is wrong. I only have that for pins 1-5. It is in it's costume now, but when I take it apart I will give it a try again!

westfw - thanks for your input too. I have to admit, I know very little about electronics. I got a bunch of these LEDs off of eBay without much knowledge on them. I know some are supposed to be 2.2v and some 3.2v.

[threebean]

Here is my costume. I had seen this costume and made mine based off it.



My son had lots of fun running around me as we were trick-or-treating.

Here is a video of the control panel.

[Amberwolf]

That's cool--John of TeamDroid is a friend of mine, though I never saw that costume of his except in photos. If it's ok with you, I'll link him to your pics.

[threebean]

Yeah that is cool, i sent him an email about my costume too.