Hi All,
I am starting to do a project with the pro mini where i need to drive this scenario.
2 strips led , those lengths , any guidance on how to achieve this , the I/o is 40ma max
2 x each strip will draw about 500ma as i calculated max and running about 1/2 that.
i would want to run this on like a lipo 3.7V ~15,000 mha. 
The Arduino’s output pin does not supply the current only a data signal so that circuit is nearly right. Put a 470R resistor in seriese with each data signal and a 470uF capacitor across the power pins of each strip.
Grumpy_Mike:
The Arduino’s output pin does not supply the current only a data signal so that circuit is nearly right. Put a 470R resistor in seriese with each data signal and a 470uF capacitor across the power pins of each strip.
can you please do a quick drawing as to what you mean?
also if i was to go with RGB strip how would this play out?
also if i was to go with RGB strip how would this play out?
That is an RGB strip? Do you mean non addressable strip? If st that would be totally different and you would need FETs to turn on each colour but you couldn't drive it very well from just a 3.7V battery.
can you please do a quick drawing as to what you mean?
From Basic Connections | Adafruit NeoPixel Ãœberguide | Adafruit Learning System
awesome, would you know an efficient way to have 48x20ma neopixel draw minimal power ?
it claims somewhere that a 15000mah on 3V strip can last about 7 hours. any thoughts?
in the pic i sent i did
48 led * 10ma at (parking light style) and 20ma when (brake style lighting)
480ma draw vs 960ma when needed here and there.
am i right to assume that the battery would last 15000mah/960ma =~15 hours or 31 hrs constant before depletion if that is all i am running (without arduino ofcourse)
would you know an efficient way to have 48x20ma neopixel draw minimal power
Just send smaller numbers to it. A brightness value of about 8 is very bright if you are looking directly at it.
am i right to assume that the battery would last 15000mah/960ma =~15 hours
In theory that is the maximum you would get. In practice batteries don't often live up to their billing. The manufacturers set the discharge rate to some secret value that makes the end mAh as big as possible. They do lots of tests to find the best discharge rate.
Grumpy_Mike:
Just send smaller numbers to it. A brightness value of about 8 is very bright if you are looking directly at it.
In theory that is the maximum you would get. In practice batteries don't often live up to their billing. The manufacturers set the discharge rate to some secret value that makes the end mAh as big as possible. They do lots of tests to find the best discharge rate.
cool so for Neopixel it works by brightness numbers, that is nice on the same I/O ex: either 5 or 8
now if i use about 8000MAH for calculation that would be more than safe correct? also what about charging a cap and releasing charge to the circuit so often to prolong life , any idea of a circuit like this?
also what would i expect the arduino to be pulling around? 50-100ma?
8000MAH
it is written 8000 mAh. What you wrote would require a small power station to supply.
also what about charging a cap and releasing charge to the circuit so often to prolong life
Pointless as it would not prolong anything.
destiny2008:
cool so for Neopixel it works by brightness numbers, that is nice on the same I/O ex: either 5 or 8now if i use about 8000MAH for calculation that would be more than safe correct? also what about charging a cap and releasing charge to the circuit so often to prolong life , any idea of a circuit like this?
also what would i expect the arduino to be pulling around? 50-100ma?
"NEOPIXEL' brand LEDs use the WS2812B chip - with an RGB 5050 LED they draw 20ma per LED, so 60ma per chip or 'Pixel' as some vendors call them.
That is at full R 255 G255 B 255 and 100% brightness.
I regularly power strips of 16/24/32 with the power pin from an ESP8266 as I am a) rarely turning all LEDs on at the same time and b) rarely turning any LEDs to full brightness.
It would help if you gave a usage scenario. If you are trying to make a fancy brake light, save your money - you can buy one that does a bunch of functions for less than the cost of the parts of using an Arduino.
pretty much the scenario in reply 3 using wireless functionality from another arduino to turn it on remotely so red color @10ma and when braking it will go to max red@20ma.
