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Topic: Long length of addressable LED's? (200ft) (Read 986 times) previous topic - next topic

Grumpy_Mike

Quote
Adding a pullup resistor to 5V on the output will make the probabilities for success with 3.3V micro even greater (preferable on a 5V tolerant pin, but the protection will usual handle it).
No it won't, have you read the specification on how much current the ESD protection diodes can take?
No nether have I , it is something the manufacturers do not specify. Only the most shoddy designer makes use of these.

Shanedm1

I'm intruding on having a soft and slow fading wave effect roll thru the length of the LED strip. So instead of a simple on or off effect that everyone had, I plan to have a kinetic effect that will add a bit of drama to the lighting.

No it won't, have you read the specification on how much current the ESD protection diodes can take?
No nether have I , it is something the manufacturers do not specify. Only the most shoddy designer makes use of these.
When using HCT you only need about 2V for high and is compatible with 3.3V logic. A CMOS input is guaranteed to work around 3.5V with 5V supply, running it at a slightly lower supply would make the input 3.3V compatible and the output would still be 5V compatible.
The protection diodes can usually handle 10mA, it is in many chip datasheets. I have not seen any value for ESP32 and would stay below 1mA. On a output the voltage will not really go above 3.3V, but will reach 3.3V.

Grumpy_Mike

Quote
The protection diodes can usually handle 10mA, it is in many chip datasheets.
Please point to a data sheet for a processors used on any Arduino that gives that figure.

You are totally missing the whole point here. We are trying to drive a WS2812 from a 3V3. We know that while it occasionally works it is outside the specifications

You are totally missing the whole point here. We are trying to drive a WS2812 from a 3V3. We know that while it occasionally works it is outside the specifications
That was the reason I specific HCT244 or HCT14, they will both do the 3.3V to 5V conversion and stay inside the specifications.

Shanedm1

I see that there are options for a board/controller.
As far as the LED strip, what are some of my options ?
My only experience is with the WS2812b so I'm  not families of the better choices, although Ifeel that 30 LED/ strip will be adequate.
Recommended to use a 24v setup.

What else?

PaulRB

#36
Aug 04, 2019, 09:22 am Last Edit: Aug 04, 2019, 09:24 am by PaulRB
I'll defintiely need the 60 LED's / meter
Ifeel that 30 LED/ strip will be adequate.
?

Paul__B

Please point to a data sheet for a processors used on any Arduino that gives that figure.
And while you are at it, point us to a datasheet for any other processor that specifies 10 mA into the protection diodes.  :smiley-eek:

And while you are at it, point us to a datasheet for any other processor that specifies 10 mA into the protection diodes.  :smiley-eek:
I was just looking at the mega 4809 datasheet, to see if I wanted a couple of nano every.

It do specify injection current, including how to calculate limiting resistors:



It is not 10mA, but 15mA or 1mA depending on conditions. With 3.3V supply a pullup to 5V must inject 15mA.

Shanedm1

My only experience with LED's is with shorter strips of 30 leds/strip. I incorrectly assumed that more LEDs meant better resolution but it's more lumens. This thread has already been extremely informative so that's why I decided that  30 LEDs/ strip is adequate.
I'm confident that I can come up with the programming and with the advice here the ha hardware selection as well.

Shanedm1

So for 30 LED's/ meter what would be the best solution ?

PaulRB

With 30 LEDs/m and 24V you would be looking at 300 individually controllable groups of 6 LEDs, requiring 1,200 bytes of ram memory. So a basic, compact, 5V Arduino like Nano, Pro Mini, Pro Micro would be fine.

Shanedm1


PaulRB

#43
Aug 05, 2019, 07:57 am Last Edit: Aug 05, 2019, 08:07 am by PaulRB
Yes, if they make them in 24V.

Be sure to check the type of whatever LEDs you choose is compatible with the FastLED or AdaFruit NeoPixel library.

Shanedm1

In orde to power them along the full length of the strip, how is that accomplished? The power wire needs to be staggered but how is that accomplished? I haven't seen anything off the shelf but I can solder some disconnects.

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