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Topic: Power supply for my LED modules (Read 1 time) previous topic - next topic

retrolefty

Quote
The other end of the chain will connect to nothing so if I just "cap" them off?


Yes, either cut them short and tape them off, or coil and tape. Just don't let bare ends touch each other.


Lefty

long_p1

And he said "let there be light"  :D

Thanks guys, I know it was simple thing but im still scared of electricity & didnt wanna waste the lights.
Now I can lgo earn how to use my Arduino to control them with PWM ;-)

I've also learnt (after reading many times), that its not good to look directly into a lit LED  :0

CrossRoads

"use my Arduino to control them with PWM "

For that you'll need a transistor to do the switching.
If you use a part like ULN2003 to control the connection from the -pin to ground, there are 6 PWM outputs on an arduino and you can individually PWM all of the modules.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

long_p1

Thanks for that info CrossRoads............... More learning/info taken in.
After some research I found this response from a "Lefty" to a similar question.

"You can just use a simple NPN power transistor to switch all those led assemblies at the same time. Either just with on and off commands using digitalWrite() commands or vary the brightness by using a PWM supported output pin and using the analogWrite(pin, value) command. A TIP120 is a cheap popular choice of switching transistor. Wire it's emitter to ground, it's base wired to a series 500-1k ohm resistor with the other end of the resistor wired to the output pin. Wire all the +12vdc wires of the led assemblies together and then to your 12vdc source voltage. Then wire all the - leads of the led assemblies together and then wire it to the collector of the transistor. Finally run a wire from arduino ground pin to the - terminal of your +12vdc power source. The power source must be rated for the total current of all the led assemblies totaled"

Is this the same in my case, if i left them as one string? I have some TIP120's that I brought with my Arduino and other bits. I also have some salvaged TIP121's.

Cheers

P.

long_p1

Great! The project is 600mA at the mo. It will go upto 1.2A in total. I'm just trying to get basic parts of a project together so I can then hit the coding side of things, then look to put it together in a more permanent/robust way.

I find learning much easier when I'm doing something wanted/needed with it.

P.

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