Ok cool, so I will use a wall charger. its rated 5v at 2.5A. I know someone told me in this topic to avoid wall chargers due to the motors stall current, but I dont have a choice. Here is link, what do you think? I should be fine right?
I will obviously have to modify the end plug(cut it off) to fit the servo shield.
As long as it is a REGULATED DC adapter of correct voltage, and sufficient current, you're good to go.
Avoid unregulated supplies used with computerised or logic controlled equipment.
-while the servo motors themselves don't need accurately regulated power... the controller chip inside the servo housing is more susceptible to noise and over voltage events.
Alright guys thanks for all the help in solving such a simple problem. I learned a hell of a-lot. And I will be using this 5v @2.5Amps REGULATED wall charger, here is link:
Since the stall current for the mg996r is 2.5 amps and it works between 4.8v and 7v, I should be fine.
The link I posted previously was not regulated.
kloud:
5v battery with at least 2.5 amp rating
Use batteries !!!
It makes testing so much easier.
kloud:
Yes my power for both arduino and sheild are separate an I'm pretty sure it pulls current from both sheild an arduino. For the d cell battery I only have 1.5v an I can't use that cause for the servo sheild cause I need exactly 5v.
Are you sure about that
lastchancename:
That servo looks like a beefy 'hobby' servo, so I doubt it is pulling much current if there is nothing attached to the spindle.(horn) during testing.OK, your existing supply (USB via the Macbook) may be under-rated for your long-term application, but finding a 5V@2A DC regulated plugpack to drive the shield shouldn't be too hard. (7-11, Supermarket, department or hobby store ? Some discarded mobile phone chargers will do the job.)
With gears attatched although the average current is low the peak current (stall current )can be high.
I would not expect a servo to be damaged by this although a wrongly specified driver chip may be.
Servos like this are designed to run off battery packs and even lab type supplies can have a problem when driving motors (Heavy inductive loads) older lab supplies were linear,modern are switch mode and the cheap ones cannot cope with inductive loads.
kloud:
For the d cell battery I only have 1.5v an I can't use that cause for the servo sheild cause I need exactly 5v.
The servo is quite happy with 6V and the 5V for the shield can be got from the 5V line on the Arduino. So four batteries in series would do you.
Technically, yes, but I considered it as part of the servo control.
But your point is valid, as the 0V return must be capable of sinking the +Vservo current.
Grumpy_Mike:
The servo is quite happy with 6V and the 5V for the shield can be got from the 5V line on the Arduino. So four batteries in series would do you.
I am sorry about going back an forth between DC regulated power supplies an batteries but, I can use 6v even though the shield said 5v because there is an input voltage regulator correct? And I guess going 1v over isn't going to matter much hmmmm....
but, I can use 6v even though the shield said 5v because there is an input voltage regulator correct?
No that is not what I said. I said use the 6V for powering the servo and the 5V from the arduino for powering the shield's logic.
On that wiring diagram you have not connected the ground to the servo.
I have no idea why you are using a motor shield anyway with that setup, it is not needed.
That diagram is incorrect cause the servo has 3 pins. Voltage ground and signal which are connected to the servo sheild. Everything else on the diagram is correct.
Voltage ground and signal which are connected to the servo sheild.
Yes but why?
You do not need a motor shield to switch the power to a servo. Just connect the servo's power and ground to your 6V supply and then connect the signal direct to the Arduino.
Agh I should have explained myself. I am building a robotic arm with 6 servos so I need the sheild to control each and before I build the arm I want to test the servos on the servo sheild.
OK still don't know why you need a shield, you can control 12 servos at the same time from an Arduino Uno and a lot more with a Mega.
OK - an 'improved' wiring diagram is attached for those that haven't read the whole thread - or are unable to 'imagine' what happens when driving servos from a microcontroller.
You may not even have a shield. or you may use an external power driver - but that is beyond the scope of this conversation.
The OP has a shield, and appears o have power drop-out issues when driving a heavy-duty R/C servo directly from the Arduino - this has yet to be determined when he implements a better power supply.,
Sorry for replying so late but ur post summarizes my problem. The arduino uno does not have enough amperage to power even 1 of my mg996r so I need an external with at least 5v at 2.5 amps. That's y I got the sheild. I will make a battery pack with 4 1.5v d cell Panasonic heavy duty battery, but I need it at 5v instead of 6. Can I use a voltage regulator? And will I have to worry about current with the regulator? Sorry this is my first time doing something like this so please bare with the questions.
The arduino uno does not have enough amperage to power even 1 of my mg996r
That is true, but you know what, the Arduino doesn't have to power your servo at all.
so I need an external with at least 5v at 2.5 amps.
Yes you do.
That's y I got the sheild.
What ever you thought the shield did you were mistaken. You do not need a shield to power the servo. You connect the external power to the servo directly and make sure the servo power ground is connected to the Arduino ground. Then you simply connect the Arduino's output pin to the servo's input pin. There is very little current flowing from the Arduino to the servo, all the power is coming direct from the external supply.
Sorry this is my first time doing something like this so please bare with the questions.
So stop arguing.
YOU DO NOT NEED A MOTOR SHIELD.
I will make a battery pack with 4 1.5v d cell Panasonic heavy duty battery,
Good connect that to the servo's power and ground, and the ground to the Arduino ground.
but I need it at 5v instead of 6.
No you don't because:-
YOU DO NOT NEED A MOTOR SHIELD.
Can I use a voltage regulator?
No need because
YOU DO NOT NEED A MOTOR SHIELD.
And will I have to worry about current with the regulator?
No need because
YOU DO NOT NEED A MOTOR SHIELD.
Are you starting to get the picture yet?
kloud:
but I need it at 5v instead
Why ?
That shield is just a bunch of connectors.
BTW
That servo is designed to allow operation with a 2S lipo pack , 7.4V.
