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Some more LED questions
cdbrown:
I've read through previous posts on illuminating the pushbuttons using LEDs. They all go into higher mcd meaning brighter LED, the amps and voltage. I didn't notice an actual size (1/4", 3/8"). I have looked at a local supplier and the size that has the right brightness is 3/8" and over. This sounds large but as I don't have a button to look at it is hard to visualise ???
I also went to this link
http://www.7volts.com/led_resistor.htm
I don't know about having LEDs in a series. I read somewhere that you add the mA of the LEDs and use that in the graph - but it looks like you can only get 2 20mA LEDs in series using 12V supply. Someone said you could get 6 or more from a 5 volt supply. Maybe I'm looking at it wrong but it doesn't work out for me.
Could someone please set me straight on this. I was hoping to wire up quite a few pushbuttons with LEDs which could mean I need a few power sources?
Very very confused ??? ??? ???
-cdbrown
Carsten Carlos:
Hi!
That graph is so confusing -I'm to busy at this moment to explain this, plus I won't work with this method anyway.
So, here are some short answers, maybe a look on my homepage can help also, I explained some things regarding LED's there, too.
If you put the LED's in series, you simply add the voltage, NOT the current! If you go with 2,2V LED's, you have to take 5-6 LED's to match. On a 5V supply you can take 2-3, with two they would have a bit to much voltage (2,5V), but this shouldn't be so much of a problem.
Don't know why you want to put them in series, either. Just put one in the button (bright 5mm LED), and get the resistor. To calculate the resistors, just look on my homepage, you will find it under "interfacing".
I hope I wrote it understable enough, otherwise just ask.
Good luck,
Carsten
Frostillicus:
I checked out your site, carsten- very cool. I'm a little new to all this, and I like the temporary set-up for your control panel. I'm gonna try that myself when I get to that stage.
LED question: I understand for some games 2 LED's blink for start 1 and start 2 - my question is what does the 3rd blink for? and what do you have it lighting up?
My guess is that it's some type of in-game signal for scoring or such, but am I wrong? Thanks!
Carsten Carlos:
--- Quote ---I checked out your site, carsten- very cool. I'm a little new to all this, and I like the temporary set-up for your control panel. I'm gonna try that myself when I get to that stage.
--- End quote ---
Thanx, you are welcome! We were quite joking here to build the entire cabinet with carton and paper ;D
--- Quote ---LED question: I understand for some games 2 LED's blink for start 1 and start 2 - my question is what does the 3rd blink for? and what do you have it lighting up?
My guess is that it's some type of in-game signal for scoring or such, but am I wrong? Thanks!
--- End quote ---
Whee, got some problems with the 3rd LED also! There was one game where the LED blinks when any coin is insert - so it is not divided between 1up and 2up. There was also a game where the LED lit when you got something special during gameplay, at least I think so - don't know where I exactly got that? ???
I wanted to put the 3rd LED under the trackball (for know I got a hacked one which can be illuminated), but this could change if I get the used Happ trackballs.
Don't wanna leave the 3rd one out, but actually I have no special idea either!
1UP:
You could always use the 3rd LED to drive your coin door lights! You might need an inverter though, so it blinks out instead of on, and then remains on the rest of the time...