Long Wires but How Long?

Hi there,

working on an installation project at the moment. I need to create an LED constellation (more than 100 LEDS)

I need an advice on how to power uo the project and also how long wires can I use.

I ll need to turn on many LEDs at the same time and the LEDs should be hanging from the ceiling or from a net places just a few centimeters below the roof. I need many of the Leds to go down nearly close to the seats so I' ll possibly need 3-4 meters for each.

Any ideas - experience?

Thank you

P.S. This is my very first post, 1000% niewbie.

mDSP

Powering LEDs off long wires shouldn't be a problem especially as you don't want to flash them at greater than 32Hz.

Thanks Grumpy_Mike,

is there anything I should take care of? Wire diameter for instance?

Any place where I can buy online wires? Are there any especially designed for LED---Arduino board or I' ll have to soldering?

Regarding the power issue, you think I' ll be ok to turn on many of them just by using the power of USB?

ta

mDSP

Any component shop will sell wires. I would use wires of 28 SWG or thicker. Yes you will have to solder them. I would use an external PSU rather then the USB as 100 LEDs is too much to drive directly from the arduino. You will probably need a transistor to drive them. Do you need to control each LED independently of the rest?

Yes, I' ll control each one independently but I' ll need many of them turned on at the same time at some points. I am thinking of multiplexing them.

Since I am an artist rather than an electr(on)ician please accept my next question... I thought I can only feed 5V to arduino via USB? If I use an external PSU isn't there a danger of melting the board?

First off don't multiplex them, you will run into trouble trying to do that over long wires. Best bet is is you use several shift registers to get an output for each LED.

Powering the arduino through an external PSU involves putting the power into Vin jack so it goes through a 5 volt voltage regulator before getting to the arduino chip.

For 100 LEDs at 20mA you will need 2A which is quite a lot of power. If you use a power shift register you will need either a 2A 5V external PSU (make that 2.5A at least to give yourself some margin) or you need to regulate a higher voltage down to 5V.

Hi Richard,

thanks for your advice. The surrounding is going to be an almost dead dark concert hall. So I' ll prefer black wire Actually I am a composer, and the installation will be an sound-light installation.

One part of the project is gonna generate and process (digitally) the sounds and at the same time I' ll use the audio data to create meaningful links to the optical domain.

Are there any tutorials on how to use external PSU with Arduino?

Also, since I am a beginner with electronics (although quite experienced with Audio programming) as a matter of avoiding a hassle of time would you (all) suggest that I prototype first on a breadboard and then use a shield and solder the final network?

I was thinking of multiplexing but Grumpy_Mike changed my mind. I am not 100% sure what (actually how many registerShift chips etc) components I need...

best mDSP