172x WS2812B LEDs with 5V 10A power supply - Arduino power and Wire thickness

[gorilla-hands]

Hi All,

Project is a digital clock display running
1x Arduino Uno
1x Power brick 5V 10A
172x WS2812B LEDs (wired in series and both ends are connected to 5V and GND)
1x 25V 1000microF Capacitor (as close to power supply as possible)
1x DS1302 rtc Real Time clock
3x tactical switches (to set time and brightness)

Power required 3x172x20mA = 10.32Amps at full brightness for the 172LEDs.
Intend to set brightness to 200 and use power management code in script to keep limit at 7A (20-30% below Power supply)

FastLED.setMaxPowerInVoltsAndMilliamps(5, 7000);
FastLED.setBrightness(200);

I made the mistake of designing and building before working out the power supply so I'm stuck with the above and need to determine

1. If the Arduino can be safely be powered with the 5V 10A power supply via the Vin pin or via the 5V without current limiting or fuses. I believe it should be OK without as amperages is pulled not pushed - but seeking a second opinion before turning it on.

2. Wire thickness from the power supply to the LEDs strip and between the LEDs segmented strips.

Approximate wire run from Power supply via LEDs and back ~4-5m. I'm not familiar with DC cable sizing and from my online research I can only find resources down to 12V. Some websites are suggesting 10AWG (6mm2) which is too thick.

Seeking real life experience and the best way to determine the wire thickness before purchase.

Hand drawn Schematic, photo of the physical clock and snip of DC Cable sizing calculator I found online attached for reference.

[gorilla-hands]

Clock display Photo.
Exceeded total attachment size for previous post.

[Railroader]

The 5 volt to the Arduino must connect to the 5 volt pin. Vin will not work at all.
Run the stuff using that 10 AWG and measure the voltage drop over that cable using a DMM.
Sense that the temperature of the cable doesn't rise to more than body temperature..

[Paul_B]

Nice assembly!

172 WS2812 LEDs at full brightness is approximately 9.5 A - close! (Not quite 20 mA per LED element.)

A UNO is an impractical form factor - a Nano would be easier to use, mounted on stripboard or a "terminal shield".

10 AWG sounds adequate. For ten Amps total, how about you feed in to each digit?

DS1302 are noted to be prone to drift.

The power supply already has a capacitor on its output. The 1 mF (1000µF) goes across the supply at the point where the data first feeds in to the strip. Keep the wires (ground, supply and data) tightly bundled together wherever they go - no open loopy bits!

Switches are called "Tact".

[DVDdoug]

10 gauge wire shouldn't be necessary unless you have a long wire run between the display and power supply. Wire resistance is a combination of gauge and distance. And/or multiple connections will share the current so a connection to each digit would mean each wire gets 1/4 of the current and 1/4th the of the voltage drop.

[u]Wire Gauge Chart[/u] with recommendations for chassis wiring, power transmission, and Ohms per 1000 ft.