Hi:
I'm going to use a servo HS-645 MG (High torque servo) to move a load of 0.5kg approx. My question is: should I use a transistor or any other extra hardware in order to prevent overload (fry the arduino)? or is it enough using the arduino to power the servo?
Thanks in advance!
The signal wire (with the pulse width signal) can be connected to the servo.
The power for the servo can not be supplied by the Arduino. You need a seperate power supply for the servo motor.
Peter_n:
The signal wire (with the pulse width signal) can be connected to the servo.
The power for the servo can not be supplied by the Arduino. You need a seperate power supply for the servo motor.
How high is the risk of blowing up the Arduino?
How high is the risk of blowing up the Arduino?
Sky.
Gilgamesh90:
Peter_n:
The signal wire (with the pulse width signal) can be connected to the servo.
The power for the servo can not be supplied by the Arduino. You need a seperate power supply for the servo motor.How high is the risk of blowing up the Arduino?
Small risk of blowing up, as either the automatic over-current/over-temp protection of the on-board 5 volt regulator or the on-board 500 ma thermofuse if using USB power will prevent lasting damage, however you most likely end up with a very unreliable system with lots of resets, freeze ups, or other weird symptoms.
Gilgamesh90:
How high is the risk of blowing up the Arduino?
Is this a serious question addressed to @Peter_n or a joke?
...R
Robin2:
Gilgamesh90:
How high is the risk of blowing up the Arduino?Is this a serious question addressed to @Peter_n or a joke?
...R
What i meant was what is the risk of connecting the servo directly to the arduino and use it.
What i meant was what is the risk of connecting the servo directly to the arduino and use it.
The servo will try to draw an amp or more. The Arduino will safely supply 40mA, so the servo probably won't even more.
Well I'm confused. Many do, in disregard of recommendations not to, power their servo via the arduino 5V pin, which can supply maybe 300-400ma and if it's a small enough servo with little mechanical load, not see any apparent problem.
Again the best advice is to power servos separately via an independent 4.8-6.0 volt DC power supply or batteries, but that does not mean one can't get away with powering one small unloaded servo directly from the arduino via it's 5V power pin. The 40 ma maximum rating of output pins has nothing to do with the subject of powering servos, at least to my mind?
The 40 ma maximum rating of output pins has nothing to do with the subject of powering servos, at least to my mind?
I guess it depends on how you intend to power the servo.
PaulS:
The 40 ma maximum rating of output pins has nothing to do with the subject of powering servos, at least to my mind?
I guess it depends on how you intend to power the servo.
Best to stick with software subjects Paul. 
The usual way to externally power a servo. If you power the servo from a 40ma pin, the servo won't move. If you power the servo from the arduino 5v pin, the arduino will probably reset due to low voltage and possibly damage the arduino.
retrolefty:
Well I'm confused. Many do, in disregard of recommendations not to, power their servo via the arduino 5V pin, which can supply maybe 300-400ma and if it's a small enough servo with little mechanical load, not see any apparent problem.
This question is about a high torque servo moving a substantial load. I think it's reasonable to assume that it will try to draw more current than the Arduino's voltage regulator can supply. The usual rule of thumb for small hobby servos is a peak of about 1A per servo. For a high torque servo under load, it might well exceed that.