Powering servos and arduino

So I want to only have one plugin for my project (a robot arm). I am using the Arduino Uno which I know I need 7-12V to power and I am using a few servos that run using 4.8-6V. Is there a way I can use the same power supply to power all of these? I have quite a few power supplies, at the moment I am using 9V 0.6A for the Arduino and I've been told I need to use 5V 2A for the servos.

I thought maybe I could just put some resistors between the power and the servos but not the Arduino? Or would it be more advisable to use two separate power supplies and just connect the grounds? I could do this but I'd rather not have two separate plugs for my project.

Thanks in advance!

Power everything from 5V, connecting the servos and the Uno in parallel (not serially, from the Uno to the servos, as many attempt to do). Connect Uno Gnd and Servo Gnds at the power supply.

It is always advisable to use two power supplies, because motors and servos tend to inject severe electrical interference into the power supply. But if you can’t, and have problems, try adding a “decoupling filter” consisting of a 47 Ohm resistor followed by a 100 uF capacitor to ground between the power supply and Arduino Vcc.

Your servos may require more than 1 Ampere each. Post a link to the product page.

I have one continuous motor for the base: https://www.ebay.co.uk/itm/SPT-Digital-Servo-SPT5325LV-360-High-Torque-Steering-Gear-for-RC-Car-Boat/233602038995?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

and am going to connect 2 or 3 180 servos for the arms: 180-360° MG90S Micro Metal Gear 9g Servo for RC Plane Helicopter Boat Car 4.8-6V | eBay

I don't think using 5V for the arduino is good is it? As it needs to use 5V but brings this down from 7-12V. Could I still run it on 5V?

I don't have any capacitors at the moment but have every value of resistor I can think of is there a way to mimic the 'decoupling filter' using just resistors?

Thanks for speedy responses!

I don't think using 5V for the arduino is good is it?

The Arduino is designed to run on any voltage between about 2 and 5V. Use lower clock speeds at lower voltages, as recommended in the processor data sheet. Arduinos have voltage regulators on board, but they are not suitable for powering anything other than the Arduino itself, except for a few small sensors and LEDs.

A decoupling filter absolutely requires a capacitor. You can salvage capacitors from discarded electronics.

The start/stall current for the Digital Servo SPT5325LV is 2.5 Amperes. Add to that about 1 Ampere each for the other servos, so your servo power supply must be capable of providing at least 5 Amperes.

Okay, so if I used one power supply that was 5V 5A to power both the Arduino and servo that would be fine? I guess that if I did that I would need to power the Arduino via the 5V pin rather than by the Vin pin? If I did this how do I wire the decoupling filter? Sorry, I'm still relatively new to this.

power the Arduino via the 5V pin rather than by the Vin pin?

Yes, because the Vin pin requires 7-12V.

Typical decoupling filter connections:
decoupler.png

decoupler.png

Okay so if I go down this route I am going to need to buy some capacitors, I've been looking and I've seen aluminium and ceramic as the two main materials which would you recommend?

Also, would you even recommend doing this? Or should I just suck it up and use the 9V .6A for the Arduino and a 5V 5A for the servos rather than using the latter for both?

Thanks!

You could try with just 5V for both, and if you have erratic or reset problems then split them up.
Connect all the supply lines at the supply; a good regulated supply, like a Meanwell, will keep the line clean.

As an example, I powered a '1284P board (which is just a '328P but with more IO and memory and 2nd serial port) and 7 stepper motors with a 5V, 5A supply and had no issues:

(sound gets a little raspy 20 seconds in as I get out my creaky chair)

I've had a look around my supplies and the highest current 5V supply I have is a 5V 3A do you think this will be okay or do I need to go out and buy a 5V 5A? Thanks!

5V 3A is NOT OK. Always use a bigger power supply than even generous allowances suggest.

"So I want to only have one plugin for my project (a robot arm). I am using the Arduino Uno which I know I need 7-12V to power and I am using a few servos that run using 4.8-6V. Is there a way I can use the same power supply to power all of these?"

Get a large power supply, 12V might be the easiest to find. Supply the arduino thru the barrel jack and put a large 5v rated capacitor between the arduino 5v pin and ground to help protect against brownouts. For best efficiency use 6v UBEC voltage regulators to power the servos from the 12v source. You need to use voltage at the high end of the servo's operating range for them to perform best in an arm setup.