Leds using a old servo board question

[Cossett]

Im planing on making my own roof clearance lights and using a old servo board to turn then on / off and my question is -
When wiring up the leds as I plan on having then on there own wired to male plugs and then soldering the female wires into 1 pos and 1 neg lead so each led can be removed seperately, do I still need a resistor for each led as Im keeping the potentiometer attached to the servo board ?
The led will be either white or orange but havent decided on the color yet and what is the max number or leds you can run from a servo control board ?

Cheers Tracy

[skeeter]

I'd really like to see pics &/or vids of how you accomplish this feat. I'm REALLY challenged with electrical stuff. Plug & play stuff like servo, esc, receiver, motors etc. I'm alright with. When it comes to thinking outside the box, that's what I struggle with.

[Krewmember]

Micro servos can draw up to 400 ~ 450mA and standard servos can draw up to 2.5 ~ 3A when stalled. Most LEDs draw 20mA, so doing some math 400mA / 20 = 20 we can determine that a micro servo control board could run about 20 LEDs and standard servos 2500mA / 20 = 125 Leds. As for the potentiometer it is just used for position feedback and does not limit voltage because servos use pulse width modulation to control motor speed. The common voltage for servos is 4.8 volts, depending on LED wavelength (Color) LED voltage can be between 1.8 and 3.3 volts so you will have to use a current limiting resistor. I cannot determine the resistors value without knowing how many LEDs you will have.




Shawn

[frizzen]

See if this helps
http://www.rctruckandconstruction.co...ad.php?t=12930

I'd run a resistor for each color at the servo board, then send low current out through your connectors to all the leds

If you know stall rating of donor servo and current requirement for the leds we could give exact numbers, otherwise keep adding until you're happy or the board gets warm during use. If it gets warm back off a couple and Y another servo board to that channel, or use a bigger servo board.

[skeeter]

Frizzen, TYVM for that link! It is very informative. Even a Polish Hillbilly Redneck like me can make sense of how you did what you done.I can't wait to try it out & see if I can make it work fir me. UNFORTUNATELY, I have to await Christmas to see if Santa brought me the new Dremel tool WITH flex shaft. I can't start new projects to modify until I get a new one.

[Nikaem]

I have used the servo boards a lot it works fine but I add a resistor to each LED the rx olnly puts out 6vdc so there is a simple chart for the value of each LED
Color resistor value Voltage Drop (V)
Red 200ohm 2
Green 195 ohm 2.1
Blue 120 ohm 3.6
White 120 ohm 3.6
Yellow 195 ohm 2.1
Orange 190 ohm 2.2
Amber 195 ohm 2.1
Infrared 215 ohm 1.7
Other 200ohm 2
I got this info from
https://www.allaboutcircuits.com/too...or-calculator/
also I have saved myself a bunch of time by using single pass rc switch
https://www.aliexpress.com/item/RC-L...ceBeautifyAB=2

you do not need the board unless you are using it as a switch. you can run direct to the battery port on the rx . I only use the 200 ohm resistors for everything some difference in light output but it is minimal hope this helps