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Topic: About a robotic arms volt (Read 236 times) previous topic - next topic

adytech13

Hello, i have a question.

I wanna make a robotic arm with 5 "Tower Pro SG90 9g" servo motors. I then wanna get this shield "https://www.banggood.com/MEGA-Sensor-Shield-V1_0-Dedicated-Sensor-Epansion-Board-p-78324.html?rmmds=search" to attach the servos to. But the Mega 2560 dont have enouhgt power to power the 5 servo motors. So the question is: How many Volts do i gonna put in the shield if i need to power the 5 servo motors? :o

Cactusface

Hi,
     You DO NOT power the servos or motors from an Arduino of any type. So you need just enought voltage that the servos need 4.8-6 volts but they could need about an Amp each so it's current that you need lots of!

If you enter the web link properly by using the right tags (just above the G in right), we can just click it and see, who wants to cut and past it? But BangGood do sell some good cheap stuff, I'm a regular customer.

Regards

Mel.
Open your mind! But not too far, your brains might fall out.
Also like Photography, model building and my 300+ Cacti and Succs.

MarkT

Hello, i have a question.

I wanna make a robotic arm with 5 "Tower Pro SG90 9g" servo motors.
These are tiny hobby servos which cannot generate much torque, the arm will need to be light and
small, and preferably counter-balanced to reduce the torque load on the servos.
Quote
I then wanna get this shield "https://www.banggood.com/MEGA-Sensor-Shield-V1_0-Dedicated-Sensor-Epansion-Board-p-78324.html?rmmds=search" to attach the servos to. But the Mega 2560 dont have enouhgt power to power the 5 servo motors. So the question is: How many Volts do i gonna put in the shield if i need to power the 5 servo motors? :o
Hobby servos are never powered from the microcontroller - they need maybe 1A each from a separate
6V supply.  The microcontroller provides the control signals, not the power.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

adytech13

I do not understand any of this :o Please use a noob-Language  :)

kenwood120s

I do not understand any of this :o Please use a noob-Language  :)

I think that is n00b language but let's try:

There are 3 wires on a servo, usually red, yellow and black (or similar).

The red line is the POWER which is what turns the motor, the yellow is the SIGNAL which is what tells the servo to turn. (Black is the ground, or 0 volts, the return for the power and the signal to make a circuit.)

The POWER must come from a battery or a wall wart or similar, since the Arduino- even though the voltage is correct at 5V- cannot provide enough current (which to be very simplistic is the amount of electricity flowing, with the voltage thought of as the pressure).

The Arduino can provide the SIGNAL, and that's what the servo library is good at: it transforms your degree wishes into an electronic signal which turns the servo, with the servo POWER coming from elsewhere as mentioned.




adytech13

Ok, i understand that, but how much voltage do i gonna put in 5 servo motors? Thanks :D

kenwood120s

Ok, i understand that, but how much voltage do i gonna put in 5 servo motors? Thanks :D
Same as to just 1 servo, 5-6V for those ones.

But it's the current you need to add up: if you allow about 1A for each, that's a total of 5A, but it's still 5-6V.


kenwood120s

#7
Sep 06, 2017, 09:57 am Last Edit: Sep 06, 2017, 09:57 am by kenwood120s
Here's a quick pic of how to connect all of that.

Note that the servo power -ve (black) must go to one of the Arduino grounds.

The yellow lines are connected to whatever Arduino i/o pins you use for your servo.attach().


adytech13

Ok thanks :D i added karma for u :DD, and last question, cuz im not sure. Do i need to put 5-6v into the shield, or can i just put the shield in the arduino mega cuz the mega has 5v? And where can i buy a this so its adding extra amps to the shield? :D

kenwood120s

#9
Sep 07, 2017, 05:13 am Last Edit: Sep 07, 2017, 05:16 am by kenwood120s
I can't really say: it looks to me like you can supply power to the shield into the blue screw terminals on the left but I don't see a link to a document so you'll need to check. But it calls itself a sensor shield and a motor's not a sensor. You would need to check the docs to see if it can be used that way- if the pins are all just connected to the Arduino pins then it probably can- but you will have to see if it can handle the current on the board.

But you don't have to use a shield anyway.


adytech13


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