Looking for a radio actuated switch thing... - Page 2 - RC-Monster Forums

12.18.2008, 08:05 PM

just curious...cant you just use a 5v relay?

BrianG · 12.18.2008, 08:07 PM

Quote:

Originally Posted by lincpimp

...I just need to find 5 white leds that have the correct resistors for use with 5v... Any ideas where to get those pre-assembled? I would rather not have to solder all of that up, and I have no idea what resistors to use...

White LEDs drop around 3.5v each, and you typically run LEDs at 20-25mA of current. So, (6v-3.5v)/0.02 = 125ohms. Resistors from 120ohm (21mA) to 150 ohms (17mA) will be perfect. Each one will need one of these resistors.

lincpimp · 12.18.2008, 08:16 PM

Quote:

Originally Posted by Andrew32

just curious...cant you just use a 5v relay?

Space is a big issue with this project. I have to fit the led control box, ubec, and whatever switch I use in a small tupperware that I have here, 1.75"x1.75"x1"... Had to custom make it to fit under the hood of the high lift...

I will order the Dual 2.5a RC Switch from robot marketplace and let you guys know how it does...

Quote:

Originally Posted by BrianG

White LEDs drop around 3.5v each, and you typically run LEDs at 20-25mA of current. So, (6v-3.5v)/0.02 = 125ohms. Resistors from 120ohm (21mA) to 150 ohms (17mA) will be perfect. Each one will need one of these resistors.

Man you are useful Brian, if only you lived closer I could bribe you and have you make all of this stuff... Would the resistor go on the neg wire? And how do you tell polarity of the led, is one of the "legs" longer than the other?