Which Arduino should I use?

Hello,
for a new project I need 50 pwm Outputs at 9V.
I don't find any Arduino that supported this requirement.
Has anybody an Idea which Arduino I could use?

Regards

Benedikt

It will be much easier to help if you provide a full description of the project including details of the devices that will be using the 9v PWM signals.

...R

48 0utputs would be three of these with your Nano:

Using one more just to make up the 50 sounds a trifle much but - it's your project!

The output is of course, 5 V, so you have to figure how to amplify it to 9 V.

Or explain what you project is and there may be simple ways around it.

Paul__B:
48 0utputs would be three of these with your Nano:

How do you know the OP wants to control servos rather than DC motors? The common servos don't use 9v.

...R

He said PWM. As far as I know, the PCA9685 is a PWM controller. Am I wrong? :roll_eyes:

Paul__B:
He said PWM.

I suspect you are well aware that "PWM" can mean two very different things.

...R

So which one might the OP be intending that the PCA9685 will not do?

As far as I can see it is a “servo shield”. It certainly has a lot of 3 pin connectors that would be used by servos. I don’t see the large collection of mosfets that would be needed to control 12 DC motors.

…R

Who mentioned motors?

Paul__B:
Who mentioned motors?

The point about my Reply #1 is that motors were not excluded from the OP's post.

In my mind when someone mentions "pwm outputs" in an Arduino context it seems reasonable to think first of the pins that support analogWrite(). On my Uno they are marked "pwm"

...R

Robin2:
It will be much easier to help if you provide a full description of the project including details of the devices that will be using the 9v PWM signals.

...R

Id like to control 10 of these(Fabrik R9C 15 watt RGBW hinzufügen Warme Weiß RGBWWW 5 farbe in1 cob led chip|Light Beads| - AliExpress) leds. Each of them has 5 channels. Every LED should be controled by its own. To dim the LEDs I need a PWM signal. So in the end I need 50 PWM Signals, by 9V. Maybe i can use transistors, to get the 9V, but I dont have any Idea to get 50 PWM outputs.

Benedikt_Dillhage:
but I dont have any Idea to get 50 PWM outputs.

Do you have any idea what would be the lowest acceptable PWM frequency?

(I'm wondering if it might be possible to "bit bang" the PWM using one or two Megas)

...R

Ah! So now we know. :grinning:

OK, so I have given you the answer in #2. Three of those modules will give you 48 PWM outputs, if you want more, you will need a fourth module.

Then you need drivers for the LED to control the 12 V supply. You need a regulated supply and if you carefully limit yourself to using either three primary colours or two white channels, you require one Amp each LED, so 10 Amps. If you can guarantee that only a few of the ten LEDs (which of course, you have to attach to a substantial heatsink, preferably fan-cooled) will be on at once, you might get by with a lesser current.

Now to drive the LEDs, you need a current-limiting resistor for each individual LED element - 3 V at 350 mA; that will be a 2 W resistor, and to control it one of the cheap FETS available on eBay - in fact an IRF520 would suffice, you could use these cheap modules.

Paul__B:
OK, so I have given you the answer in #2.

I remain to be convinced. If the device is (as the link suggests) intended for controlling servos then it will only have a very short duty cycle range.

...R

Did you even read the datasheet?

Would that not be the first step in determining its suitability?

Paul__B:
Did you even read the datasheet?

Would that not be the first step in determining its suitability?

No, I did not read it. I don't want to use the device. I just want to reduce the risk of the OP buying something that is unsuitable for his project.

You seem to know all about it but you have not provided any evidence that the module is intended for anything other than servos. Indeed when I queried its suitability for use with DC motors your reaction was "who mentioned motors" which encouraged me in the idea that it really is a servo driver. And you have not said anything like "this thing is sold as a servo driver but it can also be programmed to produce regular PWM for controlling LEDs and motors."

Perhaps you can provide some code, or a link to some, that shows it being used for producing regular PWM equivalent to analogWrite()

...R

Robin2:
No, I did not read it. I don't want to use the device.

No, you don't. So perhaps you need to pull your head in instead of purposely interfering with my advice simply because I am the one providing the advice. :roll_eyes:

Robin2:
You seem to know all about it but you have not provided any evidence that the module is intended for anything other than servos.

Evidence you say? Like referring - more than once - to the product datasheet which - if you even bothered to look - describes it as a "16-channel, 12-bit PWM Fm+ I2C-bus LED controller"? Coincidentally, exactly what the OP wants even before he fully explained it.

Robin2:
Indeed when I queried its suitability for use with DC motors your reaction was "who mentioned motors" which encouraged me in the idea that it really is a servo driver.

Because no-one other than yourself made any reference to motors. Least of all the OP as it turns out.

Robin2:
And you have not said anything like "this thing is sold as a servo driver but it can also be programmed to produce regular PWM for controlling LEDs and motors."

Opening the product datasheet to which I linked makes it instantly clear.

Robin2:
Perhaps you can provide some code, or a link to some, that shows it being used for producing regular PWM equivalent to analogWrite()

Oh, you want me to LMGTFY?

OK I guess. This would be pretty much the first hit, and it doesn't take much more searching to find the Adafruit library reference page.

But it seems that you would rather attack me than assist the OP. Sorry, perhaps it should be obvious to me but I cannot recall what has happened in the past to explain your approach; I tend to forget such things and just try to keep on - keeping on. :grinning:

No need to get all fired up.
The PCA9685 is a 16-channel 12-bit PWM chip, and it's PWM frequency can be set to suit servos and LEDs.
Most of the boards we see (post#2) are designed for servos (the 3-pin headers and scew connector).
But that doesn't mean we can't use the chip for it's true intend (driving LEDs, or mosfets to drive LEDs).

I would drive these LEDs with switching constant current drivers (PWM-ed by the PCA9685).
But that might be expensive for that many channels.
The linear way (mosfet and power resistor) is cheaper, but produces more heat (problems).
Up to OP to decide.
Leo..

Edit:
Picture of homegrown 16-channel LED driver with PCA9685 and switching CC LED drivers in post#1 here.

Wawa:
No need to get all fired up.
The PCA9685 is a 16-channel 12-bit PWM chip, and it's PWM frequency can be set to suit servos and LEDs.
Most of the boards we see (post#2) are designed for servos (the 3-pin headers and scew connector).
But that doesn't mean we can't use the chip for it's true intend (driving LEDs, or mosfets to drive LEDs).

That seems to explain the product a great deal more clearly.

...R