Xl6009 increases the voltage when a servo starts

Hello!

I have an impulse power source 5V 7A, I need to get 6V 3A for a servo motor, but when I connect my servo in the moment when it should start the currency changes from 6V to 13V on an output of the xl6009 module and it's not rotating. What is wrong?

Hi,

Tofer: I have an impulse power source 5V 7A, I need to get 6V 3A for a servo motor, but when I connect my servo in the moment when it should start the currency changes from 6V to 13V on an output of the xl6009 module and it's not rotating. What is wrong?

Sorry, none of that makes any sense at all.

Please try again to describe: 1) what power source you have 2) what type of servo motor you have 3) how are you connecting things together 4) Where does the XL6009 module fit in all of this ?

Yours, TonyWilk

Hi!

Here are the answers:

  1. My power source is this https://lib.chipdip.ru/731/DOC002731420.pdf - RS-35-5
  2. My servo is this http://www.domanrchobby.com/content/?119.html - doman 1506
  3. My servo is connected to xl6009 out. Brown servo wire to minus out XL6009, red to plus out XL6009. Yellow wire is connected to arduino nano pin 9.
    My xl6009 is connected to RS-35-5. plus to plus, minus to minus.
    My arduino is connected in parallel to RS-35-5 with Fundruino board.
    My servo works ok without xl6009 in this scheme. But I need a bit more voltage to make it rotating a bit faster. The best voltage for my servo is 6,5V. When I add xl6009 between RS-35-5 and my servo, the servo starts to make strange noises and doesn’t work. I measured the voltage on xl6009 and it goes from 6 to 13v when servo should start.

Hi,

Tofer: Here are the answers:

Great!

If you just disconnect the servo, what voltage are you seeing on the XL6009 "step-up power module" ? Have you set it for 6.5V ?

With that servo directly connected to the arduino pin, it might not work properly if you run the servo at more than 5V.

Yours, TonyWilk

Yes I set up the module to 6,5v without servo.

Have there to be the same voltage on arduino and servo? Do you think I should connect arduino and servo to the module?

Tofer: Have there to be the same voltage on arduino and servo?

Probably Yes. Some servos do not work well when they are run at a higher voltage then the controlling processor

Do you think I should connect arduino and servo to the module?

No, that would damage the Arduino

Yours, TonyWilk

TonyWilk: Probably Yes.

But actually no. You can happily run a servo at 6V5 and feed it with a 5V signal.

Hi, Where are you connecting the supply to the Arduino? What model Arduino are you using?

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom.. :)

@Tofer, please do not cross-post or hijack. Other post removed.

So how much decoupling have you got arround the servos and the boost regulator?

It is likely that the servo’s motor is generating interference that is being picked up by the regulator. Can you post a schematic of what you have.

Here is something about supply decoupling http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

Hi! Here is the scheme. I use Arduino Nano v3.0

So where is the decoupling?

I’ve read the article, but I don’t have an oscilograph and I don’t have a clue how to calculate it. (

You don’t calculate it you just do it.

Hi,
OPs “circuit”.
3e1b917058dec59878e4ec0e19fbc3160da9124b.png

Connect the gnd input to gnd output on the XI6009 unit as in the diagram below.
scheme_bbedit.jpg

I cannot find any reference that tells me if the output is isolated.
If the OP is using the Arduino gnd as reference, then this could be what is observed.

Tom… :slight_smile:

I’ve checked the gnd on xl6009 and it is already connected. Otherwise I guess it couldn’t work.

Grumpy_Mike

But which capacitor should I use and where should I plug it?

Something like in this scheme?

Hi, Yes that cap placement will be fine.

Are you measuring the voltage increase directly across the xl6009 output pads?

Thanks.. Tom.,.. :)

Can I use 0,1uf caps?

Yeah! I measure across the pads. It is 6,5v without servo and growing from 6.5v to 13v in one second with the servo in a moment it has to start.

One more question about de-coupling. Can I use with potentiometer?

As well as 0.1 uF ceramic capacitors I would also add a large 100uF or so on the output of your boost regulator. The thing about decoupling to remember is that while you can under do it it is quite hard to over so it. Their is no “do this and it is fixed” you have to try what the circuit needs. It could be that you need the Pi filter with an inductor shown on the last diagram of that page I linked to. Try it first without but if it is still a problem then see if it helps. You can also put a large capacitor across the motor when you have the Pi circuit fitted.