Help with power control and source. Alarm clock w/ high power LED
hello,
so i'm trying make alarm clock has light fades in before alarm buzzer (faux sunrise, less bright, make waking easier). i'll need high power led (either 1 or 2 3w, thinking 1 job). i'm struggling how want control power , use supply it.
control
i know led's have limited dimming capabilities trying use there. thought transistor know switch , wont able fade action. saw video (http://thecustomgeek.com/2011/08/01/controlling-high-power-or-high-number-of-leds-with-an-arduino/) , has led fade , i'm confused because i've researched says switch. mine warm white not rbg if influences anything.
second thought using variable resistor don't have experience them (nor transistors seem more simple). thinking possible power usage need 1-5w rated resistor depending on power supply.
both activated arduino. product recommendation helpful or @ least in product specs , not.
supply
so thought use arduino wall adapter , splice in set of wires led run in parallel. thinking more don't think great idea adapter meant power arduino. avoid having 2 wall outlets occupied 1 device. i'm thinking have ardunio power adapter , second adapter inside of clock casing. both adapters in parallel extension cord wall.
the leds bought warm light 3w 3.6-3.8v 700ma according product details.
if idea right 2 adapters 5v 0.7a choice right? (found old phone adapter in dad's bin of out-of-date electronics). i'd need 2Ω 1w rated resistor correct? r=v/i=(5v-3.6v)/0.7a=2Ω , p=iv=(5v-3.6v)*0.7a=0.98w. or @ low end think 2.5v should activate led 4Ω 2w
thank you!!! appreciate help.
so i'm trying make alarm clock has light fades in before alarm buzzer (faux sunrise, less bright, make waking easier). i'll need high power led (either 1 or 2 3w, thinking 1 job). i'm struggling how want control power , use supply it.
control
i know led's have limited dimming capabilities trying use there. thought transistor know switch , wont able fade action. saw video (http://thecustomgeek.com/2011/08/01/controlling-high-power-or-high-number-of-leds-with-an-arduino/) , has led fade , i'm confused because i've researched says switch. mine warm white not rbg if influences anything.
second thought using variable resistor don't have experience them (nor transistors seem more simple). thinking possible power usage need 1-5w rated resistor depending on power supply.
both activated arduino. product recommendation helpful or @ least in product specs , not.
supply
so thought use arduino wall adapter , splice in set of wires led run in parallel. thinking more don't think great idea adapter meant power arduino. avoid having 2 wall outlets occupied 1 device. i'm thinking have ardunio power adapter , second adapter inside of clock casing. both adapters in parallel extension cord wall.
the leds bought warm light 3w 3.6-3.8v 700ma according product details.
if idea right 2 adapters 5v 0.7a choice right? (found old phone adapter in dad's bin of out-of-date electronics). i'd need 2Ω 1w rated resistor correct? r=v/i=(5v-3.6v)/0.7a=2Ω , p=iv=(5v-3.6v)*0.7a=0.98w. or @ low end think 2.5v should activate led 4Ω 2w
thank you!!! appreciate help.
hi,
here example can play with... can change code "dimmer".
the 3w led "electronic brick" shown there bright. has it's own driver transistor it's easy use.
i don't think want resistors...
quote
led's have limited dimming capabilitiesum, no... when on 1/1000 of time pretty dim.
here example can play with... can change code "dimmer".
the 3w led "electronic brick" shown there bright. has it's own driver transistor it's easy use.
quote
about 2 adapters 5v 0.7a choice right?5v @ 1 amp or more good; more better , "take" current requires.
i don't think want resistors...
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