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Topic: Connect my led strips (12v) to arduino  (Read 2665 times) previous topic - next topic

KeketteStyle

Hello,

I am beginner in electronics and I would like to learn about arduino. Actually, I am working on my first project -> Build a score board with red led strips.

I bought : 
- DC12V Red led Strips Flexible 5050 SMD (5meters)
- Elegoo Carte Mega 2560 R3 ATmega2560 ATMEGA
- Salcar 12V 6A 5A Alimentation 5,5 x 2,5mm(2.1mm) for led 5050/3528/2538 Leds


I am wondering, if I could connect my 12v alim (by jack connector) to my arduino safely and do shine my leds ?

Thanks !

Julianfer5

You need to power the LED's with the power supply externally from the arduino and then run your arduino mega in parallel to the power supply and just connect the digital pin, Pretty sure the mega cant handle the current or output the 12v

DVDdoug

Correct!   The Arduino I/O pins are 5v, and rated for 40mA (0.04 Amps) maximum.   They are "signal" or "data" lines and they can't directly power anything other than one or two regular little LEDs.  (With the right circuitry, they can control  thousands of Watts, but they can't directly provide power.)

To power an LED strip you can use a MOPSFET driver.   The schematic shows a motor, but it will also work with an LED strip.   Since LEDs are non-inductive, you can leave-out D1.

You'll need one driver for each separately-controlled segment.    i.e. A single-digit 7-segment display needs 7 drivers and 7 I/O pins.  You may be able to find a multi-port driver chip, but make sure it can handle the required current.     (You notes say 5A 6A, but I assume that's for the full 5-Meters.)

And of course, your 12V power supply has to supply all of the required current.


...I recommend that you build one driver circuit and test one LED strip/segment (maybe with the Blink Example) before you build the whole thing.

Wawa

If segment current draw is less than 150mA, then you can use a TPIC6B595 shift register (per 7-segments).
Shift registers only use three pins of the Arduino, so an Uno also could work.
Example of a large digit driver here.
Leo..

CrossRoads

#4
Jul 07, 2018, 04:45 am Last Edit: Jul 07, 2018, 04:52 am by CrossRoads
Or TPIC6595 for 250mA.
TPIC6A595 for 350mA

Or my  board with 32 N-channel MOSFET transistors for higher current.
http://www.crossroadsfencing.com/BobuinoRev17/#MOSFET
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Wawa

#5
Jul 07, 2018, 04:56 am Last Edit: Jul 07, 2018, 05:01 am by Wawa
Confusing/different datasheets.
The C version is actually lower than the B version.
Look at the max ratings for "all outputs on".

The B version could drive segments with 21 LEDs (140mA).
Assuming each "section of three" of the 12volt red strip is using 20mA.
Leo..

ReverseEMF

To power an LED strip you can use a MOPSFET driver.   
A MOPSFET, of course, is a transistor made from a Mopion crystal lattice, grown in a bucket and doped with wringers.  When a voltage is applied to the Janitor, the wringers activate and swish the Mopion charge carriers, from the floor, to the sink, thus acting as a switch.  It's a fairly slow transistor, but functions very well in damp and dank environments.

Just kidding  ;D


I believe the DVDdoug meant to write MOSFET.
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Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

KeketteStyle

Thanks you guys ! I have learn a lot of things. I am building my first digit display with red strips led but something is wrong.. My leds seems not to bright enough and I dont know why ! No matter resistor I put, my leds bright same way.
My power supply is 12v 2A (I tried with 12v 6A and that's same result). I pluged my volmeter to check if it delivers 12v.
My transistor is TIP120
I am using Blink example to make shine my leds

Look at my leds closer(yes they are shining.. a little bit) :




What can i do ? Have a good day ! :)

Paul__B

My LEDs seems not to bright enough and I dont know why ! No matter resistor I put, my leds bright same way.
My power supply is 12v 2A (I tried with 12v 6A and that's same result). I plugged my voltmeter to check if it delivers 12v.
Good start.

My transistor is TIP120
Poor choice, really need a proper FET.  Should sort-of work though.

I am using Blink example to make shine my LEDs
Are you really?  Are you setting the (correct) output pin as pinMode(pin, OUTPUT); in setup?

Wawa

Is the strip bright when you connect it directly to that 12volt supply.

You could just test that by shorting collector to emitter with the tip of a screwdriver.
Leo..

KeketteStyle

#10
Jul 14, 2018, 11:40 am Last Edit: Jul 14, 2018, 11:41 am by KeketteStyle
I solved my problem. I put a wire between emitter to negative pole on my breadboard (from power supply) then a wire between negative pole to gnd (from arduino). Now it's shinning like las vegas :D

How many leds can shine with my TIP120 ? Which transistor should I have ?
I need one TIP120 per digit ? (7 segments = 42 Leds)
So I need 5 TIP120 to build my scoreBoard. then 5 * 42Leds = 210 Leds. Can i make shine these all leds ?

Paul__B

I solved my problem. I put a wire between emitter to negative pole on my breadboard (from power supply) then a wire between negative pole to gnd (from Arduino). Now it's shinning like Las Vegas :D
So there was a connection missing which was not obvious to us since your photograph was taken in darkness instead of daylight and showed only a small section of your arrangement.

How many LEDs can shine with my TIP120 ? Which transistor should I have ?
I need one TIP120 per digit ? (7 segments = 42 Leds)
So I need 5 TIP120 to build my scoreBoard. then 5 * 42Leds = 210 Leds. Can I make shine these all LEDs ?
Do you not need a transistor for each segment?  So 35 transistors.

You haven't specified the LED segments adequately.  How much current do they draw?  For the 6 LED strips you illustrate, I gather they draw 60 mA per three LED section at 12 V, so 120 mA for two sections.  As Wawa and CrossRoads have explained, a TPIC6B595 can drive eight such segments so you would need five of them for five digits.  These are serial shift registers which chain from one to the next, so you only need three Arduino pins to drive them, a Nano would do the job perfectly, a Mega 2560 is quite inappropriate.

Wawa

Seven TIP120 transistors per digit, one for each segment.

Five digits is 5*7= 35 transistors, and 35 Arduino pins.

Read post#3 again.
Leo..

KeketteStyle

Nice thanks you a lot for your answers :)
My project is growing ! I did my first digit and I handle it by remote control. However, my IR range is barely 1 meter.. How can I increase that ? I have to increase emitter or receiver ? both ? How does it works on my tv ? (on my tv, my remote control have a strong signal)

I have first components from beginner arduino kit

Have a good day :)

ReverseEMF

#14
Jul 18, 2018, 06:03 pm Last Edit: Jul 18, 2018, 06:03 pm by ReverseEMF
...my IR range is barely 1 meter.. How can I increase that ? I have to increase emitter or receiver ? both ? How does it works on my tv ? (on my tv, my remote control have a strong signal)
If you rolled your own IR transmitter, then perhaps you're not driving the IR LED with a high enough current.  OR, the IR LED you chose isn't bright enough.  TV remotes drive their LED(s) to the absolute max -- probably on the order of 50mA [depends on the LED].  This is possible because the LED is being pulsed [i.e. not on all the time].  Most datasheets indicate a pulsed current rating.  That's the one you need to use.
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Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

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