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  #1  
Old 07-20-2014, 08:07 PM
victrola victrola is offline
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Default The eternal question, which one do I need ?

Hi there!

The title says it all, I wonder which MIDI Decoder do I need ?
Here is what I'd like to do :

I bought a CREE LED like this http://tinyurl.com/ojyo86o and a Constant Current Driver like this http://tinyurl.com/nl8buwd . I don't know yet how many I'd like to control but it's between 12 and 24. I wants those LED doing only on/off at different timing.

My first question is, which MIDI Decoder would be the best and the second is, how to wire the thing to the Decodeur? Can I just hook it up directly to the Decodeur (since it's only 3V batteries) or I will need to build an extra electronic circuit?

Should I consider the MD24 instead of the MSA-P, R or MPA?

Thanks in advance!
Victrola
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  #2  
Old 07-28-2014, 01:33 AM
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John John is offline
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Quote:
Originally Posted by victrola View Post
Hi there!

The title says it all, I wonder which MIDI Decoder do I need ?
Here is what I'd like to do :

I bought a CREE LED like this http://tinyurl.com/ojyo86o and a Constant Current Driver like this http://tinyurl.com/nl8buwd . I don't know yet how many I'd like to control but it's between 12 and 24. I wants those LED doing only on/off at different timing.

My first question is, which MIDI Decoder would be the best and the second is, how to wire the thing to the Decodeur? Can I just hook it up directly to the Decodeur (since it's only 3V batteries) or I will need to build an extra electronic circuit?

Should I consider the MD24 instead of the MSA-P, R or MPA?

Thanks in advance!
Victrola
Hi Victrola, welcome to the forum.

The main consideration here is the amount of current that must be switched to control the LED.

Given the driver circuit in your link, the circuit could be controlled with a switch on the battery side or on the LED side. (Probably better to control it on the battery side--maybe the driver would still draw a trickle of current with the battery connected and an open circuit at the load.)

The LED in your link draws 700mA at 2.85V.

Given that the two batteries supply 3.0V or less, the current from the battery pack is going to be roughly 700mA or greater.

So using the MSA-R or MSA-P is out, because each is limited to controlling 500mA or less.

But you could use an MSA-T to control the driver circuit. You could wire it the same way you'd wire any other load, just like the diagram in this thread:

http://forum.highlyliquid.com/showthread.php?t=985

A different alternative is to use the MD24, MSA-P, -R, or -T to drive a secondary power relay that you supply.

Perhaps the easiest solution would be to find an LED driver that includes a low-current "enable" control input that could be driven directly by a 5V signal from the MD24 (or by an MSA-R or MSA-P).

I hope that was helpful. I'd be glad to discuss further.
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Old 08-23-2014, 12:15 AM
victrola victrola is offline
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Hi John,

Thanks for your reply! I didn't know you answered my question, I was waiting for an email notification ... my bad !

So basically, if I understand well I just have to buy single relays and that's it! I thought relay was only for high current voltage like 120 AC or heavy load. Since the current driver is only powered by 2 AA, I thought it would be possible to connect it directly to the board.

I'll give this a try for sure but my project is reported to next April. I have more time ... I'll come back ...

Many many thanks!

Cheers,
Victrola

( I have another question but I'll start a new tread )
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