I think I am overloading the data pin but I'm receiving data just not correct data

Projects General Guidance
1

I am hooking up multiple LED's to my Uno using a separate power source (currently using a 5v 20a 100w AC-DC power converter off 110 outlet) for the LED's so I don't fry the board. However, I was putting all (10) 144 LED strips on the same data pin and the programming was malfunctions. It was supposed to be blue lights but was flashing a rainbow style program.

I was reading that even in a data pin the LED will put of about 20 mA of current, is that correct?
If this is the case I need to put 2 LED strips per pin so that I can get the correct data and don't overload my pin? I'm shocked if this is the case that it was working at all and didn't immediately just fry the pin.

Also, can anyone recommend a forum to help with the battery usage needed for LED? I am wanting someone to help me check my math.

Thanks!

2

The real starting point for help will be a block diagram showing all your connections including the power supply.

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Anything but the one you're in, which is for Installation and Troubleshooting. Ask a moderator to help you find one and move it.

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I am new to this forum and have no idea how to find a moderator.
First post.

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Go to the first post, at the bottom right click on the flag. In the drop-down that will appear, mark "something else" and make your request there. Moderators will receive a notice and read it.

Continuing with the matter, do what @Paul_KD7HB asks of you, in order to help you.

6

While I am not a moderator, I do have the trust level that allows me to move posts.

Installation and Troubleshooting is for Problems with the Arduino IDE itself NOT your project. It says so in the description of the section. Therefore I have moved your post here. Please be more careful where you post in future.

You may want to read this before you proceed:-
how to get the best out of this forum

Not quite. The current drawn from an output depends on the load it sees. A current of 20mA is the amount you should let the output pin delver. Although when it delvers 40mA then it will start to damage the Arduino.
When you connect an output pin to a lot of input pins the limit on how many you can connect before it starts to fail is called the "fan out". I would have thought that you would just about get away with this.

But this is just a guess until you show us exactly what you have and how it is wired.

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You said you had some math you wanted us to check?

8

So the maths was
144 LED strips at 60mA per LED = 8.6 Amps.
10 Such strips = 8.6 * 10 = 86 Amps.
So your 20 Amp power supply will not cut it.
You need three of them. Join the grounds but do not connect the positives together, arrange them on different strips.

9

Hello, thank you for the switch and link for info @Grumpy_Mike. Sorry for the delay I am working, and this is just one of my many projects so my responses may be delayed but I appreciate everyone's quick reply.

I just got some time to look at the link you sent and read a little more about this forum group. This was a recommendation from someone I know that was trying to help me, but I started to ask questions he was not sure about and he recommended this group. I am super new to working with boards, electronics, and battery power. I have done a lot of research but and I am understanding more as I go and still need someone to explain in that way and I will try and provide as much details as possible. I am a performer and I like to create new things for my acts. This is the largest project idea I have taken on and I feel totally out of my element, like my brain pictures the product but doesn't know how to finish it or if what I am doing is even possible after really digging in and figuring out that LED's pull way more than I thought. :frowning:

Below is my entire Project- LED & power portion

I was testing on 10 stands with my helper with an AMP clamp, but he said it wasn’t pulling correctly for some reason and I didn’t quite understand why.

But I have a total of 18- 3.2’ strips per side. (See my not so good drawing)

I think the reason for all my confusion (well besides being super new to this) is I wasn’t sure the exact way to read the data sheet. Not knowing a lot about this, I was reading it like 3 different ways and coming up with 3 different answers. And I assumed the higher answers had to be wrong because I didn’t think LED’s would be pulling that much power. It looks like I was wrong.

LED’s

Data sheet details –

  1. Led strip welded by 0.5m is very normal in an electronic product, not a quality problem. if you mind this, don't place order!

  2. WS2812B Led strip can be cut buy each "one" led chip!

  3. IP30: Non-Waterproof.

IP65: Waterproof in Silicon Coating.

IP67: Waterproof in Silicon Tube.

  1. WS2812B Led Strip work withDC5V, and it need a WS2812B Led Controller to Control it.

About how to choose Led Power Calculates The Whole Led Strip Watts:1. One Led Chip is About 0.3W, when you buy it is 1m 144Leds / m (Total Led Strip is 144Leds), so 0.3W * 144= 43.2W

  1. and this Led Strips Work 5V, So 43.2W / 5V =8.64A (about 9A), We Know This Led Strips Better At Least 8.64A (about 9A)

Also, the other data sheet that I have that came with the LED’s says the power is 0.1w-0.3w based on what you are having your LED’s Do/ color amount. I was just planning on trying to do one color to keep down on the current pull. See math below.

Finding the draw of the LED’s

Using this Formula to find Amp- Strand Watts / Battery Voltage = Amp

1 color 0.1 = .1 x 144 = 14.4W / 12V= 1.2A per Strand (18strands x 1.2A =21.6A)

2 color 0.2 = .2 x 144 = 28.8W / 12V=2.4A per strand (18strands x 2.4=43.2A)

3 color 0.3 = .3 x 144= 43.2W / 12V =3.6A per strand (18strands x 3.6 =64.8A)

Questions – Am I doing this right or wrong?

This would be taking it from the converter voltage

  • 1 color 0.1 = .1 x 144 = 14.4W / 5V= 2.88A per Strand (18strands x 2.88A =51.84A)
  • 2 color 0.2 = .2 x 144 = 28.8W / 5V=5.76 per strand (18strands x 5.76=103.68A)
  • 3 color 0.3 = .3 x 144= 43.2W / 5V =8.64A per strand (18strands x 8.64 =155.52A)

Converter

5V 20A 100W

Question - Data sheet says to use this size converter, but can I use it for all 18 LED’s or would I have to have a converter for every 16.4’?

I have purchased 2(one for each side)

Current Battery for each side- What we originally thought we needed but now I’m seeing this 12.8V 20Ah 256 Wh

*I need to be able to keep the battery as light as possible. This battery below is as heavy as I should go. But this battery is pricy, and I need 2. I would prefer to stick with the one above but maybe I will just have to rethink the entire thing based on what you all think. This project is way more expensive than I was anticipating and not knowing what I was doing ahead of time I was not able to count the cost but trial and error as I go.

Fuse

If I don’t have the Amp right, I will have to get a different fuse.

Arduino Uno (purchased 1 from Adafruit and one from Amazon)

Question- how many LED’s can I put to one pin? I’m sorry, I’m not understanding the math you are getting.

I feel like this is a lot of information and questions but please let me know if I can provide anything else to better help. I appreciate everyone’s help!

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Well it is not the way it is normally done.
Using the power of a thing can be misleading. As you know the power is calculated by multiplying the voltage by the current. That is fine when talking about a light bulb in normal circumstances but is confusing when considering designs in electronics. When we design something we always work with voltage and current. The power is only useful to make comparisons with other lights.

So in post #10 that data sheet should be interpreted as you needing, as it says 0.1 W/ LED, which is somewhat of a useless figure. It shows that you need 5V, so considering any other voltage, like 12V is useless because you can't use this voltage, it has to be 5V. So lets convert that into current.
Using W = E x I
Where W is the power in Watts, E is the voltage in volts and I is the current in amps we need to rearrange the formulae to make I the subject of the equation, this gives:-
I = W / E
and plugging the values into that we get
I = 0.1 / 5 = 0.02 Amps or 20 mA which is exactly the figure I used in my calculations.

So for each LED colour you need 0.02 Amps so for full colour (all three colours) you need 0.06 Amps.
It is then a simple matter of multiplying this figure for the number of LEDs you have it total. As I showed before and it comes to a big number.

So how to reduce this? There are a few ways to do this but it is a matter of trading off brightness and or number of colours to be on simultaneously.
For a start there is an overhead current of 1mA for each LED you have irrespective if it is on or off, something not mentioned in the data sheet but something we know here following members experiments. This is for powering the controller chips embedded in each LED.

Each LED can have a brightness level set by the software, and many driver libraries have an overall brightness level settable in software. Some use the numbers 0 to 255 others use percentage levels 0 to 100. If you set these then the software makes sure you can't exceed these levels. So setting these levels to say half the maximum will half the maximum current your strip will need in terms of current. This of course will not be as bright, but the logarithmic response of the eye means that lower brightness levels look brighter that you would think.

Limiting the number of colours will work as well, but it is quite easy for you to make a mistake with the software and have more than the number of colours you want on at any one time, so I would not recommend that way of limiting the current.

An other way of reducing the current is to reduce the voltage, so instead of using 5V you can use a lower voltage, down to about 3.3V (or 3V3 as it is normal to write). However, you have to limit the voltage fro the Arduino to the same voltage level as you are driving the LED strip from.

Incidentally you should have a 510R resistor in series with each data input to each strip to help suppress reflections from the line of data. This could help with your original problem, as could powering the strip from both ends.

It is also good practice to put a large capacitor on the power supply pins of each strip to help smooth out the current surges during the PWM used by the LED controller to vary the brightness.

Hope that clears some things up.

14

Although I am almost totally in agreement with all this reflection, I would like to make some points.

Yes, we can power the entire system, including the Arduino itself, with 3V3 through the 5V pin. But we will have to be extremely careful and disconnect the 3V3 power supply before connecting the USB port for reprogramming.

Although not critical, it seems a bit high to me, values between 300 and 450 Ohm are usually recommended.

Not at the source is advised on each strip.

In these leds PWM signals are not used, data frames are used, the brightness of each led is one more byte within the frame for each led, which will memorize its own data until further order.
As an example I use the following assembly / guide for these types of LEDs:
tira
Greetings.

15

I think you are misunderstanding what I mean here. PWM is not derived from the controlling Arduino, it is generated by the control chip that is embedded with the three LEDs in the WS2812 part. It is how the chip controls the brightness of each individual LED. This internal PWM still produces current fluctuations which need smoothing.

I wasn't suggesting that either, I was suggesting powering the LEDs from 3V3 and cutting down the 5V signal from the Arduino with a buffer or open collector gate. So the Arduino is still being powered from 5V.

Well I recommend 510R. So shoot me.

The end you have the capacitors on doesn't matter if you are doing it right and powering both ends of the strip like you should be doing.

16

Thank you for all this info! I need to review and figure out if I understand everything that is being said and then I will be able to get back to you all with questions.

17

Or even:


Clearly this is arbitrary.

18

True, it seems quite arbitrary, I have never seen such low or high values. Adafrut, for example, advises 470 Approx. and it is one of the highest found on the net.

Dear @Grumpy_Mike , I certainly misunderstood you when it comes to PWM. As for the 3V3, why have two different power supplies? Arduino works correctly at 3V3 and in this way you do not need level adapters.

19

Well no, it will work at 3V3, but to run it at that voltage the use of a 16MHz clock is outside the specification given in the data sheet. So it is likely to be not reliable at that clock speed and voltage. It might very well function for a time but running outside the manufactures specifications is never a good idea.

20

I would like you to tell me where in the datasheet it indicates that because I can't find it. Moreover, boards with a voltage selector are marketed:
https://www.dx.com/p/opensmart-easyplug-5v-33v-compatible-uno-r3-air-atmega328p-development-board-for-arduino-uno-r3-2609462.html#.YsmfGjdBx9M
I have one of them and I assure you that its clock at 16 MHz is completely stable at both voltages.