[TriEmbed] Driving 32 5v relays

[Richard Prevette]

The answer the first comment is mostly money.  I am using c9 size Christmas
lights for a yard display.  I have 16 PVC pips painted like candy canes
with two lights per pole.

The second comment looks like just the ticket but would it have to be wired
to car battery or a 12v wall adapter with at least
a 3 amp rating?

On Thu, Jul 16, 2015 at 10:16 AM, Adam Haile <email at adamhaile.net> wrote:

> Stupid question... why not just use digital LEDs?
> https://www.youtube.com/watch?v=_nbuSgYoCSQ
> Full disclaimer: I have a tiny business that does LED lighting stuff, but
> I am also just a huge fan of digital LED strips since they take away
> complications like those with relays and such.
>
> More on your original question... no, no... not a resistor to do 14v ->
> 5v! You would be dropping 9v and @ 3A be dissipating 27W!   I have bins
> full of buck converters like the one linked below that will do 8-23V input
> and output a nice steady 5V. They work great and are very efficient.
>
>
> http://www.amazon.com/Nextrox%C2%AE-Display-Supply-Converter-Module/dp/B00CBCGAL8/
>
> On Thu, Jul 16, 2015 at 11:10 AM, Richard Prevette via TriEmbed <
> triembed at triembed.org> wrote:
>
>> I am making a Christmas light display using 32 relays.  Using arduino and
>> four 74HC595n shift registers.
>> The relays are SRD-5vDC-SL-C.  Here is the question: I may be
>> misunderstanding but the datasheet states each
>> relay takes 72ma.  I put  a meter across the power and that seems right.
>> At one point all relays will be on at the same time.
>> That looks like I need a power source that will supply about 2.3 amps.
>> 32 x 72 x 1000 = 2.3a (Correct ?)
>>
>> I have a Dell AC adapter that states output at 14v dc and 3 amps.  All I
>> need is a resister to lower 14 to 5 volts and
>> I good to go?
>>
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