RGB LED relay question for series / parallel

[StealthRT]

Hey all, i have drawn what i think is the correct way to hook up my RGB LED in series.

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The way i see it is that:
- The relay will be turned on by the digital pin on the ardunio using 5v.
- Then the relay will connect and produce the 0v (gnd) to the RED LED pin on the RGB led.
- The Anode will be powered by 12v that will be in series of 19 LED's per 12v

Here is the datasheet:

https://www.lemicro.cn/rar/SRD%28T73%29.pdf

The black dots are the relay pins. 3 on one side and 2 on the other. From the picture below it seems as though i did hook it up correctly? With the coil being on the side of the 3 dots...

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I used 3.3v as the forward voltage since that's the highest it will need to go (blue). So i figured the RED and Green would work just fine with that?

As for the ASCII drawings i changed the specs listed to:

12v Source voltage 
3.3 diode forward voltage 
20 diode forward current (mA) 
18 number of LEDs in your array

Solution 0: 3 x 6 array uses 18 LEDs exactly
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms
 * *+----|>|----|>|----|>|---/\/\/----+ *R = 120 ohms

However, i have been told that i would not be able to connect this via series. How can i connect this using parallel?

David

 

[ronsimpson]

18 RGB LEDs? or 6 RGB LEDs?
What is the LED part number?
You want to control all the LEDs so any combination can be on or off.
You want an color, R, G, B, R+G, R+B, G+B, white, on any LED.

 

[StealthRT]

It seems i can only drive 4 @ 12v since they take 3.3v at max (green and blue)

I am looking to do
-red
-green
-yellow (red+green)

I am using an arduino

David

 

[ronsimpson]

See attached data for LED.

The common pin goes to ground.

The RGB pins go to a resistor and then to (+).

This can run from +3.3, or +5 or +12.........

I think you are trying to add R+G+B. 2V+3.2V+3.2V=8.4V It does now work that way.

 

[StealthRT]

See attached data for LED.

The common pin goes to ground.

The RGB pins go to a resistor and then to (+).

This can run from +3.3, or +5 or +12.........

I think you are trying to add R+G+B. 2V+3.2V+3.2V=8.4V It does now work that way.

But i have a common anode for all the RGB leds...

David

 

[StealthRT]

Was the re-drawing correct?

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Does not click when i apply ground and 5v to it....

David

 

[ronsimpson]

Lets get the relay working first. (I don't know why the relay)
First apply 5 volts across the relay coil and see if it clicks. No 2N2222. You might try reversing the coil. (put +5 on the other end)

 

[StealthRT]

Yes it clicks when i have the positive on top and negative on bottom of the relay.

 

[StealthRT]

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[ronsimpson]

Next add the transistor in and see if the Ardunio can turn on the transistor. Do you have a meter? When the Ardunio pin is at 0 volts the collector of the 2N2222 should be at 5 volts (if the relay is in circuit) and then Ardunio is at (about 5 volts) the transistor should be at 0.3 volts more or less.

 

[StealthRT]

Yes it does have .3v when i connect the 5v + 1k resister on the base and test the collector. Without the resister its 5v on both.

David

 

[ronsimpson]

Yes it does have .3v when i connect the 5v + 1k resister on the base and test the collector. Without the resister its 5v on both.

Part1) good. do you hear the relay click. It should. You should have 4.7v across the relay coil.
Part2) The poor little 2N2222 needs a resistor on the base. Never connect 5V to the base. (5V and 1k to base is good) 5v and no resistor=replace the transistor.

 

[StealthRT]

I have the relay hooked up with a 1k and it seems not to have any output for the collector.

I tested out the transistor with my digital volt meter and put the + on the base and the - on the emitter and it gave a value of 9.xx or 10.xx. so it seems to be working?

When i hook it up to 5v (using the 1k as well) and test out the output of the collector its 0v for the collector and .33 for the emitter.

David

 

[StealthRT]

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Values i get:

From 5v to the base i get 0.77v.
Out of the emitter 0v
Out of the collector 0v

 

[ronsimpson]

OK I am lost. The orange/white wire labeled ground....I thought it should go to the transistor's collector. Are you sure the emitter is connected. The other orange/white wire, is it connected?

 

[StealthRT]

I must be lost as well.

On that sheet there under the relay it has

1) Emitter
2) base
3) Collector

So on my breadboard its

EBC

Unless i am incorrect?

The emitter should be ground, correct? Or should the emitter be the 5v line to the relay?

 

[ronsimpson]

Emitter = ground
I see the emitter, the 4 holes below are open.

 

[StealthRT]

Alright, still getting 0.77 at the base and 0v for the collector..

David

 

[StealthRT]

**broken link removed**

Corrected the drawing to show current hook up state.

 

[ronsimpson]

I can see better.
Take the orange wire "collector" and connect to +5. Take the orange wire "ground" and connect to the collector of 2N2222.