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Topic: knight rider project using 1 watt LEDs (Read 1 time) previous topic - next topic

dc42


Zapros cct is fine ...


I'm not so sure. If the MR16 LEDs are halogen replacements, they almost certainly contain a switching regulator and a large input capacitor. This will give rise to large current pulses when the mosfet switches on. Preferably you should tap into the switching regulator PWM control signal in the built-in regulator. See this thread: http://arduino.cc/forum/index.php/topic,139792.0.html.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

af77

I'm also going to be using 2 TLC5940's.  If I ran the LEDs through a ULN2803 and then through the TLC5940, would that work instead of using the NPN transistors?  In my project, I will be using 6 LED strips like in the example in my first post, and 24 of the 1 watt LEDs.  If what I suggested won't work, what would?

cjdelphi

http://www.ebay.com/itm/1x-5x-MR11-G4-Warm-White-LED-Bulb-Spot-Light-Lamp-Downlight-1W-DC-12V-/350668699726?


you're not going to use those things are you?



http://www.ebay.com/itm/5pcs-New-1-Watt-1W-RED-Super-Bright-50-Lumen-LED-Lamp-Light-Panel-PCB-MOUNT-RL1-/120901084245?pt=LH_DefaultDomain_0&hash=item1c26442455

or

http://www.ebay.com/itm/5pcs-New-1-Watt-1W-RED-Super-Bright-50-Lumen-LED-Lamp-Light-Panel-PCB-MOUNT-RL1-/120901084245?pt=LH_DefaultDomain_0&hash=item1c26442455


I was thinking of doing the same thing, I had my circuit setup to use 5mm LED's...  which left me with a dilemma, space/pins - So i used the ULNxxxx whatever number as a darlington
transistor array supplying up to 500ma ...

http://www.youtube.com/watch?v=KzY8epcaTW8

That's my Greenie in Action, but like you I wanted something more Powerful.. like the 1watt LED's.


Use 1 watt LED's with a bunch of 2222a transistors and create a monster bright knite rider kit, that or go buy 12v automotive lamps for the car and paint them all red :)

af77

Would I need the 2222a transistors if I used the ULN2803 darlington (since that has transistors inside)?

cjdelphi

1. 2222's are cheap and each can handle up to 1 amp.
2. unl can't supply more than ?00ma... per pon

But if you're using low brightness leds below ?00ma whatever the datasheet says ...go for it.. i thought you were using high power led's...

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