Wemos D1 Mini and WS2812B

[zanga]

Hi,

What can be the maximum length of a WS2812B strip that can be used with a Wemos D1 Mini without the use of an additional power supply ?

Thank you !

[Wawa]

About 7 LEDs if you calculate 60mA (max) per LED and 80mA for the ESP module.
There is a 500mA fuse beween USB socket and 5volt rail.
Leo..

[INTP]

Without additional power source . . . . what's your first power source?

[zanga]

Many thanks for your reply!

I was thinking to use a 2A phone wall charger.

[INTP]

Between 30 and 60 ish LEDs. If you have 30/meter then 2 meters is doable. Obviously if it's 60/meter then 1 meter is it.

It depends on what your program/pattern is. How many LEDs you plan on having on at a time and how bright. If it needs to be full bright as a lighting application, stay on the lower end. Patterns with moving lights or twinkly bits can go to more.

[PaulRB]

I don't know if the Wemos board can handle 2A. I would not want to take the risk. You might burn your house down. Presumably you want to use the Wemos' micro usb socket to connect the charger to the strip. It would be safer to cut off the usb plug and solder on a barrel plug. Then use a barrel socket, with separate wires going to the strip and the 5V pin on the Wemos (plus common grounds, of course).

[Wawa]

I don't know if the Wemos board can handle 2A.

Not through the USB socket.
There is a series circuit of a 1Amp schottky diode and a 500mA polyfuse between USB socket and 5volt pin.
Leo..
 

[INTP]

Obviously with a line from power source to led strip, not through the board.

[zanga]

Thank you all for your help !

I wanted to do it thru the board only but I see now that there is no chance for that, so I will use a second power source to be on the safe side.

[PaulRB]

You need only one power source. But you must not pass all that power through the Wemos board. You must split the power coming from the power supply, with separate wires going to the Wemos and to the strip.

[zanga]

Many thanks for the explanation Paul, will do exactly that (still waiting for the strip to arrive ).