Help with LED control schematics
i making led light stick ir control change colour. schematics made. there mistake ? misunderstand ? if yes, please forgive me, complete noob , here learn. going add 5v regulator attiny85 power supply. , 380ohm resistor pin5,6,7 corresponding transistor's base pins. planned use s8050 npn transistor.
how calculate things:
1. rgb led strips using rated @ 15w/metre @ 5v . power supply using 6v 4xaaa battery .i apply p=iv , 2.5a/metre of current. calculate current used in 60cm of led strips (2.5/100*60) , 1.5a current per 60cm. devided value 3 , 0.5a each red, green , blue pin.
2. next step, found s8050 dc current gain (hfe/beta) 40 , apply formula ic/ib = b (ic = 0.5a , ib = unknown, b=40). ib of 0.0125a. mean need 0.0125a of current in order fully-on transistor @ ic=0.5a @ 6v.
3.to find resistor value attiny85's pin, apply formula ib = (vb-vbe)/rb (ib=0.0125, vb=5 because power supply of attiny85 5v not 6v , vbe=0.7v , rb = unknown) , value of rb = 376ohm approximate 380ohm.
another issue didn't know how write code. analogwrite seem didn't work attiny85 sincce there's 2 analog output controller. or delaymicroseconds work ? could'nt figure out how write code. new arduino. know should start @ basic first need project done. , please forgive language. didn't know english well.
thanks lot.
how calculate things:
1. rgb led strips using rated @ 15w/metre @ 5v . power supply using 6v 4xaaa battery .i apply p=iv , 2.5a/metre of current. calculate current used in 60cm of led strips (2.5/100*60) , 1.5a current per 60cm. devided value 3 , 0.5a each red, green , blue pin.
2. next step, found s8050 dc current gain (hfe/beta) 40 , apply formula ic/ib = b (ic = 0.5a , ib = unknown, b=40). ib of 0.0125a. mean need 0.0125a of current in order fully-on transistor @ ic=0.5a @ 6v.
3.to find resistor value attiny85's pin, apply formula ib = (vb-vbe)/rb (ib=0.0125, vb=5 because power supply of attiny85 5v not 6v , vbe=0.7v , rb = unknown) , value of rb = 376ohm approximate 380ohm.
another issue didn't know how write code. analogwrite seem didn't work attiny85 sincce there's 2 analog output controller. or delaymicroseconds work ? could'nt figure out how write code. new arduino. know should start @ basic first need project done. , please forgive language. didn't know english well.
thanks lot.
1) sounds ok
2) want saturate transistor @ data sheet , see says saturation voltage. gate current associated voltage, indication of current need supply base.
3) can't supply 6v attiny chip, exceed maximum voltage. better using 3 aa batteries, run off voltage fine.
you not time out of aa batteries @ sort of current though.
for ir detector need seriese resistor in supply , large capacitor ground. see says in data sheet.
a word of caution, don't think ir remote library works on processor because lacks hardware timers, not 100% on check.
2) want saturate transistor @ data sheet , see says saturation voltage. gate current associated voltage, indication of current need supply base.
3) can't supply 6v attiny chip, exceed maximum voltage. better using 3 aa batteries, run off voltage fine.
you not time out of aa batteries @ sort of current though.
for ir detector need seriese resistor in supply , large capacitor ground. see says in data sheet.
a word of caution, don't think ir remote library works on processor because lacks hardware timers, not 100% on check.
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