arduino and servo motor not working

Other Hardware Motors, Mechanics, Power and CNC
1

hello,

I am trying to control servos using firefly and grasshopper.

I have connected it correctly (as far as i know) following tutorials. The servos receive a signal and power from the arduino board. I can tell this because the servo is squeaking and when i change the number slider the pitch of the squeaking changes. I am assuming this is because it doesnt get enough power??

Can anyone help me please?

Michael

2

The servos receive ... power from the arduino board.

No, don't do that! Give them their own power, and join that power supply's ground wire to the Arduino ground.

Edit: Yes, the tutorials show a servo powered from the Arduino; it's generally regarded as bad practice, even if it might work for one lightly loaded servo drawing little current.

More edit: Zoomkat's well known schematic shows how.

servo conns.jpg
servo conns.jpg790×194 10.5 KB

3

Hi

Thanks for the reply. I will test this when I have time.

However, I have seen micro servo motors work without any independent power supply so I am thinking that the power is not the problem.

I am using the tower pro sg90 servos.

4

OP:

I am assuming this is because it doesnt get enough power??

Me:

Give them their own power

OP:

I am thinking that the power is not the problem.

If you search the forum for servo problems, I'd bet 90% of the problems are power related, and of those, 99% are due to powering from the Arduino pins.

I will test this when I have time.

No rush.... it's your project :stuck_out_tongue:

5

mboalch:
Hi

Thanks for the reply. I will test this when I have time.

However, I have seen micro servo motors work without any independent power supply so I am thinking that the power is not the problem.

I am using the tower pro sg90 servos.

Servos, like all motors, can put out dangerous inductive spikes on the power supply, and
certainly lots of noise, and usually crow-bar it down to a few volts when under load.

Just don't share power between motors and microcontrollers, its really not a good idea.
Remember if the Arduino is powered from USB you are risking damaging the host
computer, not just the Arduino.

6

Depending on the USB power supply and existing loads on the arduino, a 9g servo may operate unloaded powered from the arduino. A significant number of servo issues posted in the forum turn out to be poor/inappropriate power sources such as powering from the arduino 5v.

7

Lets face it, 95% of servo related issues are probably power-related!