Arduino Forum

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 !

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

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 (http://www.gammon.com.au/motors).   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.

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. (https://www.sparkfun.com/products/13279)
Leo..

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 (http://www.crossroadsfencing.com/BobuinoRev17/#MOSFET)
(http://www.crossroadsfencing.com/BobuinoRev17/32Mosfet%20Rev6%20SMD%20Diodes%20complete.jpg)

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..

To power an LED strip you can use a MOPSFET driver (http://www.gammon.com.au/motors).   

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.

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) : (https://zupimages.net/up/18/28/otvu.jpg) (http://zupimages.net/viewer.php?id=18/28/otvu.jpg)


(https://zupimages.net/up/18/28/4btr.png) (http://zupimages.net/viewer.php?id=18/28/4btr.png)

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

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?

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..

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 ?

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 (http://www.ti.com/lit/ds/symlink/tpic6b595.pdf) 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.

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..

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 :)

...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.

Hello guys, I am beginner at electronics.. I am building a scoreboard for my baseball team and i would like to connect my 7 segments to a shift register.

I success to use shift register and make shine 8 leds one by one. My circuit is :
(https://image.noelshack.com/minis/2018/29/5/1532118839-fcwcp4tiu9vllye-large.png) (https://www.noelshack.com/2018-29-5-1532118839-fcwcp4tiu9vllye-large.jpg)
(https://www.instructables.com/id/8-LED-Knightrider-Using-Shift-Registers-With-Ardui/).

theses leds are on 5v

Now I want to replace these 8 leds by my 7 segments (12v and 1 segment = 6 leds).
So I connect my 12v jack on arduino and I replace pin 5v to Vin. Then I add transistor to connect my segment but it doesn't work... My circuit : (https://image.noelshack.com/minis/2018/29/5/1532119006-snapchat-1907817005.png) (https://www.noelshack.com/2018-29-5-1532119006-snapchat-1907817005.jpg)

(on this picture,my jack is off, but trust me, i tried !)

I am using the same arduino code as above.

Where is my mistake ?

Use a shift register that can switch 12volt/150mA.
Like the TPIC6B595 (ebay).

This page (https://www.sparkfun.com/products/13279) might interrest you.
Leo..

ouch price is expensive !
I saw some projects using shift register 74HC595 to their score board (also with 12v leds).
https://www.instructables.com/id/Remote-Controlled-Arduino-Scoreboard-using-LED-Str/

Can you help me to use this shift register (74HC595) with my leds 12v ??

ouch price is expensive !
 
I saw some projects using shift register 74HC595 to their score board (also with 12v leds). Can you help me to use this shift register (74HC595) with my leds 12v ??

Do you call $0.50 for a TPIC6B595 expensive?

Sure, you can use the 74HC595, but you have to add a transistor to each output.
That could get messy and expensive.
Leo..

I talked about SparkFun Large Digit Driver :p

I got already 74HC595 and transistor TIP120. With this shift register, I have to use 5v for shift register and 12v for leds ?

Ahh, I see this is a cross-post.

https://forum.arduino.cc/index.php?topic=556791.0

Cross-posters are time wasters.
I'm out.

Before to use Ir remote, actually I got USB cable to power my arduino (5v) also my shift register. And I got a power supply (12v) for my leds. I wonder, why I could have not only 1 power : both for my arduino and leds ??

how it looks ? (https://image.noelshack.com/minis/2018/29/6/1532176530-snapchat-1340791622.png) (https://www.noelshack.com/2018-29-6-1532176530-snapchat-1340791622.jpg)

Before to use Ir remote, actually I got USB cable to power my arduino (5v) also my shift register.

What does the IR Remote have to do with 5V power from your USB cable?

And I got a power supply (12v) for my leds. I wonder, why I could have not only 1 power : both for my arduino and leds ??

If what you're asking is "Why can't I use my 12V supply to also power my Arduino?" 

The short answer is "You can."

The long answer is:

An official Arduino [can't vouch for clones] can easily take 12V.  Just connect it to the Power Jack [either with a plug {get the polarity right}, OR solder it on to the board {get the polarity right}].

BUT, because the LEDs will use a fair amount of current, you need to take care in your power connections.  Safest way is to run separate Power and Ground wires to each thing you are powering.  So, separate wires to the Arduino, and separate [fatter] wires to the LED string.

Thanks you ! I never plugged power jack (12v) because I was affraid to fry my arduino lol

Thanks a lot ! Actually I am using Transistor TIP120 (for each segment) and shift register 74HC595. I want to make my circuit more simple. What do you think about TPIC6B595 ? Someone said "he's big brother of 74HC595". It can replace both tip120 and 74HC595 ?

What do you think about TPIC6B595 ? Someone said "he's big brother of 74HC595". It can replace both tip120 and 74HC595 ?

I've never used a TPIC6B595, but from the datasheet I see that each output can source up to 150mA continuous, and 500mA pulsed [Pulse duration ≤ 100 μs and duty cycle ≤ 2%] at up to 50V, so if your LED strips can be driven by that, then Whoo-Hoo! 

Check out Figure 6 and Figure 7 on the Texas Instruments datasheet: http://www.ti.com/lit/ds/symlink/tpic6b595.pdf (http://www.ti.com/lit/ds/symlink/tpic6b595.pdf)

As for logic compatibility, I don't see anything in the datasheet [cursory look] that claims pin-for-pin or logic compatibility with the 74HC595, so, perhaps pull up each datasheet and do a comparison?  It is a serial to parallel shift register with an output latch, so it's at least the same functionality.  And it seems to have the same control pins [again cursory look].  So, it sounds like you're in business.

Thanks you! I never plugged power jack (12v) because I was afraid to fry my Arduino lol

It should not damage it - as long as you mean 12 V from a regulated 12 V supply, and not 13/6 V or a car battery.  If you connect anything more than a few TPIC6B595s to the 5 V however, it will likely overheat and shut down intermittently.  It would be better to use one of the switchmode "buck" regulators readily available to feed proper 5 V to the Arduino via its 5 V terminal.

What do you think about TPIC6B595? Someone said "he's big brother of 74HC595". It can replace both tip120 and 74HC595 ?

See reply #11.  Given you are using only two of the three LED sections which will draw just 120 mA for each segment, the TPIC6B595 is the perfect solution.

I've never used a TPIC6B595, but from the datasheet I see that each output can source up to 150mA continuous

Rubbish!

Yes. TPIC6B595 for 150mA current loads per each output.
If you need even more, than TPIC6A595, 350mA outputs.

Both can only sink current - so 12V to the + of the strip, the - of the strip goes to the TPIC output which acts as a switch to Gnd.

@KeketteStyle, please do not cross-post.  Threads merged.

If you connect anything more than a few TPIC6B595s to the 5 V however, it will likely overheat and shut down intermittently.  It would be better to use one of the switchmode "buck" regulators readily available to feed proper 5 V to the Arduino via its 5 V terminal.

I'm probably misreading this, but if you are saying that the 5V regulator on the Arduino board, can't drive more than a few TPIC6?595s?  If so, consider that [from the datasheet] I_CC MAX is 5mA and TYP 0.5mA, then, at a conservative 100mA max from the Arduino regulator, that's 100mA/5mA = 20, worst case.  In other words, at least 20 TPIC6?595s can be powered by the Arduino 5V regulator.  And, possibly even more, since the regulator current limits at 500mA.  So, it would be a matter of heat caused by dissipation due to drop out voltage. [Unless we're talking about something other than an UNO -- wasn't able to determine, for sure]

See reply #11.  Given you are using only two of the three LED sections which will draw just 120 mA for each segment, the TPIC6B595 is the perfect solution.
Rubbish!

Why "Rubbish"?  According to the datasheet, even if ALL of the Drains are sinking the Absolute Maximum 150mA continuously, is acceptable for less than "extended periods".  So, 120mA on one or more Drains, even simultaneously should be just fine if intermittent enough.  90mA is the Recommended Nominal.  So, does "Rubbish" refer to this?

So, does "Rubbish" refer to this?

Read more closely - and then read CrossRoads' answer.  :smiley-roll:

Hello guys ! @ReverseEMF, you're giving too much information than I can't understand :D. I repeat, I am a beginner.

Good news, my scoreboard project is growing :
(https://zupimages.net/up/18/31/klvm.jpg) (http://zupimages.net/viewer.php?id=18/31/klvm.jpg)

I have build first 2 digits but I noticied something.. More leds segments are ON and less leds shine. How can I give same voltage/Intensity to each led segment ?

This is my circuit :
(https://zupimages.net/up/18/31/pasr.jpg) (http://zupimages.net/viewer.php?id=18/31/pasr.jpg)

I am using 1 ULN2803 per digit and I connected together 2 shift registers. Someone can explain me how to make brighter my leds ?

thanks you guys. I wish you good holidays ! :)

You need to check your 12 V supply voltage for the different combinations of LEDs.

Check the common ground connection to Arduino, 74HC595s, ULN2803s and the 12 V supply.

I'm not on holidays any time soon.

I have build first 2 digits but I noticied something.. More leds segments are ON and less leds shine. How can I give same voltage/Intensity to each led segment ?

Sounds like you have too few resistors in your design. Each LED, or series of LEDs, needs its own current limiting resistor.

Ok Paul I will check I Come back :)

I have 0 resistors :o that s mean is bad ?? It can explain performance of my leds?

What's the current of a LED row, and the power of your 12V supply?

OP is using LED strips, with resistors on the strip.
So no extra resistors needed.
Leo..

What's the current of a LED row, and the power of your 12V supply?

See first post.

And answer #7.

6 LEDs per row.
Someone have a good Idea ? :)

I still think that the supply voltage is important. Check the voltage when only few segments are lit, and when more are lit. Fractions of a volt may make a difference, i.e. a switching transistor already may cause problems. I'd try to increase the supply voltage to 14V or 15V, if the strips support that.

If I read you correctly, you're saying that in some cases, when more than one LED strip is powered, all of the LEDs in those strips, dim down, as if the addition of one or more strips is loading something down...is that right?

And, assuming I got that right, here are a few possibilities:

• Upon close examination of the photo you supplied [https://zupimages.net/up/18/31/klvm.jpg], I see what appears to be fat, foil ribbons running to the various LED strips.  In a few cases it looks like a couple of LED strips are "daisy-chained" together,  In other words, a foil ribbon goes to one LED strip, then from the other end of that LED strip extends another foil ribbon until it reaches yet another LED strip.
  
  If that's the case, and if these are power lines, then what could be happening is, the daisy chained path may be presenting a high enough series resistance as to inject a significant voltage drop, thus dimming the LEDs.  Because of the fairly sharp LED Forward Voltage curve [i.e. exponential relationship between forward voltage and current], it doesn't take much of a voltage drop to cause a significant dimming.  
  
  You really should run separate power lines to each LED strip, all running back to a common point, as near to the power source as possible [or if that's not practical, then you need a hefty "power buss" that those lines can run to].  A power buss is merely a conductor with sufficient bulk to minimize voltage loss at the highest in-circuit current levels [which is, usually, a combination {or adding} of all the simultaneous currents that will flow through the buss].
• Another possibility is the overloading of the power source.  If ALL of the LEDs are dimming at once, then that points to the Power Source as the problem [or it could be a high resistance point in a common power line--see #3].  If the power source voltage is dipping because too much current is being drawn [or because the power source is failing], then that will cause the LEDs to dim.  Once again, it doesn't take much of a voltage dip to dim an LED.
• Similar to #2, if there is a common power line, or common connection point from the power source, this might be the source of the dimming.  A way to test for this is to get a small[ish] gauge wire [i.e. a fat wire] and, when you see the dimming [of the LED(s)], jumper across all potential problem sources--i.e. provide a temporary "good connection".  If the LEDs brighten up, you're closing in on the culprit.  Process of elimination will guide you to the weak link.  If any of the LED current is traveling down any of the buss lines on that protoboard, then THAT very likely could be the source of the dimming.
• The ULN2803s have internal current "clamp" to the tune of 500mA on each output, and an overall limit of 2.5A.  If more current than these limits is occurring, that would cause a dimming.  So, a current inventory might be in order.
• Another possible source of dimming could be in your code [I don't see a listing anywhere].  If there is any sort of multiplexing or PWM involved, and if the pattern of this changes, such that the duty-cycle is different when the dimming occurs, then that's your problem.  This could occur if, say, a code loop executes faster when only one LED strip is lit, but runs slower when two, or more, are lit.  Something like that.  This is unlikely, but I mentioned it for completeness ;)

Thnaks a lot Reverse :) My power supply was dying.. I changed it and now it works perfectly !
I'll send some pictures when I finish my board.
See you :)

Hola, I have some problems :(

I was running my scoreboard, after 1 hours, my arduino mega fried.. (saw sparks on ship in middle board). My arduino mega was very hot ! Why it fried ?
On my scoreboard I have :
- power supply 12v 2A (to connect my Leds)
- 7x2 segments (=2 digits). Each digit = 6 Leds. Each segment runs on 12v
- Each digit are connected to ULN2803 then to shift register
- I have resistors only on my segment leds

(https://zupimages.net/up/18/34/v06j.jpg) (http://zupimages.net/viewer.php?id=18/34/v06j.jpg)

Maybe I should use 9v ? Arduino uno is better than arduino mega ? I forgot some resistors ? Tell me please :)

See you guys !

Based on your limited "schematic" [more like a block diagram], things seem to be arranged correctly, so:

• Something happened related to something obscured by lack of information.
• Something just, plain-and-simple, failed on the Mega (it should be able to handle 12V just fine, and it doesn't look like [again, based on sketchy information] anything is drawing excessive current from the Mega)
• Maybe water splashed on the Mega -- that would do it -- especially salt water!

Sparks on ship or strip?

Replace the sparkling item and continue.

Sparks on my arduino mega :(
here : (https://zupimages.net/up/18/34/3u4e.jpg) (http://zupimages.net/viewer.php?id=18/34/3u4e.jpg)

No water, It was running close of me then I saw that.

It works well for 1 hour and then... boom

Maybe I should reduce voltage ? (my arduino is burning, that's normal ?)

You could do a quality check on all items, including power supplies, but I fear that you can't do that :-(

Why aren't you  using TPIC6B595 for the segments? One shift register per digit, vs 2 chips. No problem driving 9 LED strips either.

Here's a board I offer that will drive 12 digits, driving 3 and 6 LED strips

https://www.youtube.com/watch?v=6HZ0Mr51jUY (https://www.youtube.com/watch?v=6HZ0Mr51jUY)

(http://www.crossroadsfencing.com/BobuinoRev17/2014%20board.jpg)

http://www.crossroadsfencing.com/BobuinoRev17/ (http://www.crossroadsfencing.com/BobuinoRev17/)

CrossRoad, Tpic6b595 Can replace uln2803 + 74hc595 ?

This is my circuit :
(https://zupimages.net/up/18/34/na97.jpg) (http://zupimages.net/viewer.php?id=18/34/na97.jpg)

What do you think ?

TPIC6B595 Can replace uln2803 + 74hc595 ?

Not "can", absolutely should!

OP did already get that advice 45 posts ago, and ignored it.
Leo..

Sometimes, in the process of learning, repetition helps.  :smiley-cool:

Used to be very popular in primary school, not so sure what they do nowadays. :smiley-eek:

CrossRoad, Tpic6b595 Can replace uln2803 + 74hc595 ?

As stated a few times already, yes.

Thanks and sorry guys, this is my first arduino project and there is too much information, I can't assimilate all of these info :)

Keep in touch, I'll come back to show you my project

It works well for 1 hour and then... boom

Was that a one-time event?  Could be a coincidence.