Question about Power Supply

Hi, I have a project where I need to control 7 servo motors (Mg90s) from an Arduino UNO. I understand that each servo motor can operate correctly at 6V and take max 500mah, so a 6V 3.5A power supply will be needed.

But I have two problems:

  1. I want to use a laptop charger that I have in store that supplies 12V 5A, but this would destroy my servo motors, so I need help dividing the voltage from 12V to 6V to end up with a 6V 5A power supply. there is a lot of information on the internet that explains how to divide voltage, but I am a little scared to work with a high amperage :v, so I want to be sure how to do it).

  2. The second problem is that I also need to power the Arduino UNO, the easiest option is to take a phone charger and connect it directly, but it would be somewhat inefficient to use two chargers. So I want to use the same charger used by the motors to power the Arduino, which would also need to divide the voltage and I don't know if the amperage too.

I would be very grateful if someone told me which components to use in order to use my laptop charger as a power source for the Arduino UNO and servo motors.

My Laptop Charger:

I already know that there are some pages that talk about how to divide the voltage, but when a high amperage is already handled (after 1 amp), things are different and more expensive components are used. And as I said, I am a little scared to lose my engines or worse, so I need your help.

Thanks!!!

What I have in mind (I don't know what components to use to divide the voltage with a high amperage, that's why I show it as a box)

Forget voltage division regarding powering things.
Most likely You need more than 7 x 500 mA. Look for the data for stall current. That’s the current needed at start.

Apparently the stall current is 650mah, you are right, 3.5A would not be enough, but it is not a problem because the charger provides 5A, which would be more than enough for 7 servos and the Arduino.

And since there is no problem with the amperage, I have to decrease the voltage from 12V to 6V. Do you know what component I can use?

Use a minimum 5 amp buck converter to make 5 volt out if the 12 volt.

Use this to convert the 12V to 5V, and send the 5V into the USB connector. The easiest is to cut an old USB cable and wire the 5V into the (normally) red and black wires.

tobsun.jpg

tobsun.jpg

It would be even easier to connect the 5 volt to the 5 volt pin.

https://articulo.mercadolibre.com.mx/MLM-586477535-xl4015-modulo-regulador-step-down-50w-5a-cdmx-electronica-JM?matt_tool=48904454&matt_word=&matt_source=google&matt_campaign_id=11714912137&matt_ad_group_id=113017550359&matt_match_type=&matt_network=g&matt_device=m&matt_creative=482511924687&matt_keyword=&matt_ad_position=&matt_ad_type=pla&matt_merchant_id=117915919&matt_product_id=MLM586477535&matt_product_partition_id=353037831509&matt_target_id=pla-353037831509&gclid=Cj0KCQiAqo3-BRDoARIsAE5vnaIPa22Px3F9TfDo7q1mcupDmjELVCTRBXvbfL_gbCYcNUdDj-IWgUaAl3CEALw_wcB

I found this, I guess it's exactly what I was looking for right? Thank you!!!

Taking advantage of your kindness :v, I have one more question. Since the Arduino will draw the necessary amps to power all the components it has connected, there is a risk that the Arduino will draw more amps than it can handle if I connect a wrong component. The point is that I also want to connect an LCD and an SD card reader, should I connect them directly to the power supply (5V 5A) or feed them from the Arduino which is also connected to the power supply?

It looks costly to me. Check Ebay for step down converters.
Yes, connect every device to the +5 of the convertrr.

SteveMann:
Use this to convert the 12V to 5V, and send the 5V into the USB connector. The easiest is to cut an old USB cable and wire the 5V into the (normally) red and black wires.

tobsun.jpg

It is a good option, but it is more expensive than the first option, but thank you very much for that information, I will save it in case I expand the project and need more Amps.

Railroader:
It looks costly to me. Check Ebay for step down converters.
Yes, connect every device to the +5 of the convertrr.

Oh no, it is not expensive, it is the currency of my country, it would be like 2.5 dollars, it is cheap.

That's a lot different. I thought of 54 USD....

Thanks a lot for all the help, really!

Besides, if I want to connect an SD card and an LCD to the Arduino, can I feed these two components from the power supply? Since the SD card can take 200mah, what can cause the Arduino to handle more current than it can handle right?

Just add the current consumtion of all devices and check ii doesn't exceed the capacity if the 5 volt source.

Ok, thanks for all!!! :smiley:

Servo motors can make a lot of noise on the same supply as the Arduino.