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Topic: Review my simple Schematic (Read 456 times) previous topic - next topic

Bjerknez

I'm going to use Wemos D1 Mini and Wled for controlling my two WS2811 5V LED Strings. This is two strings with total 100 LED's that teoretically draws up to 6 amp with full brightness.

Since this is 5V i think i can power my Wemos together with led strings like the schematic below?

I also is thankful for all suggestions regards to get the schematic better. Do i need capacitors etc.?


Wawa

Power is ok, but your 5volt addressable LEDs might not be happy with the 3.3volt logic of a WeMos.
Should use a logic level converter.

Has been pointed out here many times before.
Do a search on this site.

Don't forget the capacitor on the power supply of the first LED.
Leo..

Bjerknez

#2
Nov 06, 2020, 08:03 am Last Edit: Nov 06, 2020, 08:04 am by Bjerknez
Power is ok, but your 5volt addressable LEDs might not be happy with the 3.3volt logic of a WeMos.
Should use a logic level converter.

Has been pointed out here many times before.
Do a search on this site.

Don't forget the capacitor on the power supply of the first LED.
Leo..
Thanks :)
I have testet it with 3.3V logic and it works fine.
You ment a capacitor right before the led terminals on schematic?

EDIT:
I tested the 3.3V logic without resistor...

Bjerknez

What wire gauge and traces for the 6 amp line and ground do i have to use on the PCB?

aarg

What wire gauge and traces for the 6 amp line and ground do i have to use on the PCB?
Big ones.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.


aarg

#6
Nov 06, 2020, 03:27 pm Last Edit: Nov 06, 2020, 03:30 pm by aarg
It depends on the connectors, the thermal requirements, the PCB specs... all things you didn't reveal (and more... is it 6A continous or peak, etc.). So, "big ones" is a completely reasonable response. Wire current carrying capacity is something you can look up, it's standardized.

Also what PCB? You never said...
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

Bjerknez

It depends on the connectors, the thermal requirements, the PCB specs... all things you didn't reveal (and more... is it 6A continous or peak, etc.). So, "big ones" is a completely reasonable response. Wire current carrying capacity is something you can look up, it's standardized.

Also what PCB? You never said...
Its just plated 3mm big holes in a 1.6mm PCB with 1oz traces. I'm going to solder 14awg wires (or so) directly to holes and to my led string. 
6 amp is max teoretical draw mentioned in the first post. In real life i have measured the led string to draw around 3-4 amps at most. 

Paul__B

Ignoring the matter of level converters (74HCT14), your diagram is almost correct.  You show the ground wire to the WeMOS D1 Mini attaching to the start of the LED strip; the 5 V wire should also attach similarly at the LED strip.

All three wires should run together as a bundle from the LED strip to the WeMOS D1 Mini though I suspect it will as a matter of practicality, be only a few inches away.  The power cable should most certainly be twin cable.

Bjerknez


SteveMann

#10
Nov 07, 2020, 06:41 pm Last Edit: Nov 07, 2020, 06:49 pm by SteveMann
Thanks :)
I have testet it with 3.3V logic and it works fine.
You ment a capacitor right before the led terminals on schematic?

EDIT:
I tested the 3.3V logic without resistor...
You still need the resistor to reduce noise on the data line and I've never used a capacitor on the data line.
According to the WS2811 datasheet, anything above 1.75V will be seen as a logic high- I only use ESP boards and have never used a data level converter for outputs.  If the first LED is several feet from the ESP, you do need to raise the level of the data.  I use either a 74LS244 or a sacrificial WS2811 LED at the ESP to do that.

Here is the wire I use:




You can get it here.


18/3 speaker wire will also work, but it is usually more expensive as audio enthusiasts are easily duped.



Fritzing pictures are NOT schematics. I don't speak Fritzing.

Please do not ask for help by PM. I will not respond. If you need help, post a question on the appropriate forum.

Click on Add Karma if I helped you.

Bjerknez

It would not work with the resistor on data line, so i removed it. I use 22awg cable, but decided to only use one string (50 leds). Works perfect. No flickering.

It has light up my front door for 5 hours now with full brightness without problem, and animations works fine.

I use no level shifter. Just a stright line from D4 to the logic in on the leds.

runaway_pancake

"Works like a sharm"
Looks like < 100.
"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

Bjerknez

Not finish. Just for testing.

Bjerknez

#14
Nov 09, 2020, 06:36 am Last Edit: Nov 09, 2020, 06:36 am by Bjerknez
I am also a little wiser now i think, when it comes to choosing of 5V/12V LED strings. I think 5V led strings is fine for small projects with only a couple of leds. For bigger projects i think 5V is useless regards to voltage drop.

My understanding so far is that 12V is a lot easier to use in larger projects. ยจ

Therefore i do not see the benefit of 5V in small projects either, because it's just easier to stick to 12V that can be used in booth places.

I think 5V is best for battery usage, but who lights up led strings with batteries?

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