People hate resistors for their LEDs

I found this true over the years. People just hate to use resistors with their LEDs.

Here is a popular program, Fritzing's download page:

http://fritzing.org/download/

An otherwise pretty good tutorial for arduino with LabVIEW:

http://vishots.com/getting-started-with-the-labview-interface-for-arduino/

Then they should use a driver that uses a single resistor to set the overall max current for the device, and offers software control of the brightness. MAX7219/7221, TLC5490, WS2801, WS2803, etc.

Thoughts 2 & 3 seem not to have anything to do with resistors.

Engineers don't like fritzing.

CrossRoads:
Engineers don’t like fritzing.

I am no engineer but I didn’t like fritzing either after tinkering with it a bit. That was a year or so ago. Now I find some use for fritzing. You can draw up simple diagrams with their breadboard and post the image. With an actual breadboard and parts (who has time to build a voltage divider?!), you take a shot at it, the perspective is always screwy. With pins, headers, wires and the breadboard not at the same depth of view, the picture could easily be misleading. But with fritzing it’s all good.

"You can draw up simple diagrams with their breadboard and post the image." which we engineers don't like because the parts show up as block boxes with no clues as to what the wire is connected to. even a simple transistor - no way to tell if connected to Emittter, Base, Collector - all the stuff that a simple schematic shows. Post the schematic, that is so much more informative. I have yet to see a decent schematic posted that was created in fritzing.

CrossRoads: Thoughts 2 & 3 seem not to have anything to do with resistors.

look at the pictures

and fritzing does schematics, the idea is you biuld it on your "breadboard", then it makes the schematic, then I think it can do simple PCB stuff, but no one ever makes it that far.

Look at the pictures?

you biuld it on your "breadboard", then it makes the schematic

There's the problem then - user gives up control - or more typically has no clue - and then autocreated schematic is just crap.

Osgeld:

CrossRoads:
Thoughts 2 & 3 seem not to have anything to do with resistors.

look at the pictures

and fritzing does schematics, the idea is you biuld it on your “breadboard”, then it makes the schematic, then I think it can do simple PCB stuff, but no one ever makes it that far.

I actually use it to design and print PCBs. Had to switch from Eagle when I decided to start selling some of my projects, didn’t want to drop the $80 on a license. It does have some bugs, so I usually just use the breadboard view to drop parts on, then do my own routing in the PCB view. I have never been able to make a schematic look nice, so I usually ignore that view.

Any other software recommendations? I was going to try out Eagle again, but it seems you have to actually mail them a form now (is this the 1920s?). Scratch that, found the download link.

But back on topic, at least the Blink Tutorial has a series resistor....

Eagle is more like $40 USD for lite license. I have it, wishing I could afford license upgrade but don't have the dough.

CrossRoads: Look at the pictures?

you biuld it on your "breadboard", then it makes the schematic

There's the problem then - user gives up control - or more typically has no clue - and then autocreated schematic is just crap.

yea man, he linked two sites, if you look at the picture on them its a led with no resistor, leading back to

Thoughts 2 & 3 seem not to have anything to do with resistors.

yea they do, click on the link and look at the picture, no resistors on led's

sheesh :P

You're right, I hadn't opened the links. Saw /download on the first one, assumed it was a lead in to download fritzing.

Hi Guys,

hope this isn't a proverbial grandma-egg-sucking moment, but you can get leds suitable for 5v use with built in resistors UK: http://www.rapidonline.com/Electronic-Components/5mm-Red-LED-5V-60-150mcd-Diffused-55-2670/?source=googleps&utm_source=googleps

I think there are 12v ones too.

I don't like fritzing either, I prefer circuit diagrams every time.

I will say that the high power LED's that are sold with the current limiting already on the heatsink are awfully nice to use, even if they are a bit more expensive. I've paid as much as two dollars a watt, but usually they end up being around half that, at a buck a watt, give or take, for whites in the 2watt range. Feed them anything from 3.2 to 6v, they self limit at 500ma or thereabout. Here's a link:

EDIT: Got diverted while getting the link, hehehe:

http://www.ebay.com/itm/10x-2-3W-LED-3-2-6V-500mA-Warm-White-for-Camping-Light-DIY-/180857225621?pt=Lamps_US&hash=item2a1bee4195

Now, I will say that it does require extra heat sinking in actual operation- but running a couple in series from 12v works great. I suppose running three ought to be fine at 12v. Its a lot of light for cheap money... The link has them at under a buck each for ten. I am not connected to it in any way other than saying I've bought them and though they seem a little dimmer than expected given the power draw, but not so much that you'd actually care much... I use an NPN transistor to switch the ground side to provide PWM.

![](http://i.ebayimg.com/t/10x-2-3W-LED-3-2-6V-500mA-Warm-White-for-Camping-Light-DIY-/00/s/ODI0WDEwMjQ=/$(KGrHqNHJEgE+eDo7sikBQW!7JTYDQ~~60_35.JPG)

They are awfully convenient to use, when you don't want to diddle around with constant current sources...

"Here's a link:" or not ;)

There are 12V LEDs with resistors for sure, with mounting hardware even. Pricey for experimenting, great for final installations. Some examples http://www.superbrightleds.com/cat/led-wired-bolts/

When doing a quick test, I like to plug one leg of a standard led into the Arduino female. I have some 560 Ohm resistors soldered onto flex jumper wires at one end, and croc-clips on the other. This is so I can clip the croc onto the other LED leg, and plug the loose end of the resistor into another female. The croc-wire-resistor makes it easier to move between components and arduino pins.

Come to think of it a croc-resistor-croc might also be useful.

I have similar - a couple of LEDs with a resistor soldered to one of the legs.

CrossRoads: I have similar - a couple of LEDs with a resistor soldered to one of the legs.

yea I have a small handful of those

I got lazy and bought 50 "prewired for 6V red LEDs" from eBay. Like these: http://www.ebay.com/itm/50-Pre-Wired-6v-3mm-Red-LEDs-PreWired-Red-6v-LED-/160596848997?pt=LH_DefaultDomain_0&hash=item2564517165

I had a UV led on a pot and made the mistake of turning the pot too low. Weird smell.

Hardest part for me is trying to remember how to determine the resistor value, which I have to go search on to re-check even if I do think I remember just to be sure which I'm not. So I aim high as I don't like leds hurt-my-eyes bright anyway. I run 340+ ohms at 5V with standard 5mm reds for indoor use. Maybe they'll live longer, certainly they use less power.