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[on:]

Hi,

I'm creating an interactive light sculpture. I am using 4 ultra sonic sensors to control 2x 5m LED strip tape from here: http://www.amazon.co.uk/gp/product/B008EMZYWK/ref=oh_details_o02_s00_i00

I understand how to connect my sensors to my arduino and have them feeding in info nicely, so far so good. However I do not understand how to interface my LEDs with arduino.

I have an arduino uno and a sainsmart relay: http://www.amazon.co.uk/gp/product/B005WR734M/ref=oh_details_o00_s00_i00, I have 2x strips of led tape, see link above and 2 drivers which are 12v DC 25W power drivers, constant voltage.

In order to power my LEDs I take a plug from the main and the positive and negative go into the driver and then out to the positive and negative to the LED tape. (this is without arduino)

The information I am missing is how the circuit above gets wired up my relay and arduino to be able to control the LED tape?

Can anyone help me please?!

Aphra

[Reply #1 on:]

Aphra,

Going on what you have written big fella it would seem as if you have not wired the LED strips into the relay back that you have bought. you have wired them directly onto the LED driver. Is this correct??

If so then when you turn the power on the LEDs should light up straight away, not controlled by the arduino.

If you wish to control them with the arduino you have to wire the LED strips through the relay bank you bought and control the relays with the arduino.

I guess the real question is.... What exactly are you trying to achieve? Are the LEDs going to just turn on when a sensor is triggered?? Are they going to get brighter as someone gets closer??

Send some more info our way and im sure someone here will be able to point you in the right direction.

Cheers DuaneAUS

[Reply #2 on:]

This relay board needs a Vcc, Gnd, and then 8 Digital connections.
The arduinos digital pins, when turned HIGH, they will output 5v on the pin.  So say you connect pin 0 on the arduino to IN1 on the relay board, the relay will switch when pin 0 is turned HIGH and and activate the associated output that is connected to the relay board on the other side.  

A relay is kinda like a light switch that can be thrown using programming and basic electronics.

Using this relay board, you won't be able to do any animations other than just turning things on and off at certain times.  

[Reply #3 on:]

Hi there,

Thankyou for your responses.

I didn't realise that by using a relay I can only turn things on and off, this is not what I want to do. I want to be able to fade in my LEDs as a person moves closer to my sculpture.

So my new questions would be these:

Do you know how I wire up my LED tape to my arduino to do this?
I know that somehow I need my LED tape to be connected to an arduino digital pin and the my LED tape also needs to be connected to 12v and ground (from external power supply driven by a driver) but how do I make my circuit?
Do I also need the drivers to power my LEDs? If so how does this fit into the circuit?
Do I need something to protect my arduino?

If you would be able to help me further I would greatly appreciate it,

Aphra

[Reply #4 on:]

Yes, if you aren't experienced with electronics, it would be better to just ask the questions first before buying.  Its not as straight-forward as some people think.

Do you know how I wire up my LED tape to my arduino to do this?
I know that somehow I need my LED tape to be connected to an arduino digital pin and the my LED tape also needs to be connected to 12v and ground (from external power supply driven by a driver) but how do I make my circuit?
Do I also need the drivers to power my LEDs? If so how does this fit into the circuit?
Do I need something to protect my arduino?

You are asking questions without giving necessary information to be able to help you.  Don't worry, its natural. So here is what I need to know first:
1) How many connections are there to the LED tape and what are their labels?  (I'm guessing a 12v led1, led2, led3?)
2) What Arduino are you using?
3) Maybe.
4) We'll figure that out later

[Reply #5 on:]

Sorry about that, I am new to this forumn thing and have not had help yet!

1. My LED tape only has two connections -+ it is a single colour tape
2. I am using an arduino uno
 
If you can help that would be great.

Thanks.

[Reply #6 on:]

   I would try to use either power transistors like the tip 36 b or led strip amplifiers. I picked up a few for $3.75 each on ebay.

[Reply #7 on:]

Simple NPN transistors connected like this and driven from a PWM pin will let you fade your strips.
LED strips typically have the current limit resistor built in.
N-channel MOSFET can be used also.