Go Down

Topic: servo and power source (Read 878 times) previous topic - next topic

bebus77

Hey everyone,

I'm pretty new to everything that concerns power voltage and resistors, my field is software. I have my arduino set so that when I press a push button, it moves a servo and blinks a LED. now, everything works smoothly if the arduino is plugged to my computer via USB, but when I plug it to the wall to a 9V adapter, the servo starts to behave crazy and it gets hot. Can you please suggest me a nice way to solve this ?

Thanks for answers,
David.

Msquare

Do not use the 9v.

The servos typically need 6V. Your USB only gives 5V which is enough (but not really enough)

bebus77

My servo works from 4.5 to 6 volts. There is no way to use 9V ? Because I need to make the whole thing portable and I've created a 9V battery to 2.1 mm adapter

retrolefty


My servo works from 4.5 to 6 volts. There is no way to use 9V ? Because I need to make the whole thing portable and I've created a 9V battery to 2.1 mm adapter


The problem with those small 9vdc batteries is that they have a high internal resistance and cannot supply the current required to operate servos. Get a proper battery source, even AA cells wired in series might work depending on the size and load driven by your servo.

Lefty


Msquare

Lets see .... 9V makes the Servo go HOT ... is it wise to use 9V ?

On the other hand, if you got more time/money, you could put in a 6V regulator.
OR
You could power the Servos of the 5V pin on the Arduino, the onboard regulator has lmited the 9V to that. It can not take unlimited power, so depending on your size of the servos it mau fail occasionally as a servo takes too much power making the Arduino reset or "go funny".
OR
You do two batterypacks - one that does 6V which only goes to the servo + and -, and another that does at least 7v and goes to the Arduino power jack (and which only needs a small current, ie the 9V battery will do). Remember to connect the Gnd(-) of the two battery packs together.

bebus77

Thanks for answers: I thought about something simpler that may work.
Why not using the USB port which is 5V as the power source ?
I can easily create an adapter from a 9V battery to USB, using the female socket, a resistor and a 5.1 Zener diode
Do you think this may be a good solution ?

AWOL

Even simpler would be four AA batteries.
Or AAAs if you're short of space and not too worried about running time.
9V batteries are a waste of resources.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Go Up