Go Down

Topic: Using a Transistor to power Technic Servo (with PWM) (Read 2122 times) previous topic - next topic

08yamaha600

Hey everybody I'm an electronics student working on a final project for graduation. I am trying to learn the basics of the Arduino Uno and I was able to drive a small Technic continuous running servo using the write functions out of pin 9.

I want to begin driving multiple servos and want to begin using transistors to turn them on, my only confusion lies in the PWM of the servo control module. There are 3 pins on the servo control -- orange, white, and black.

-Orange: Power
-Black: Ground
-White: PWM for control

I am using 3904 NPN transistors. My question is, should I be using the 3904 as common collector or common emitter? And can i drive the PWM (white) pin of the servo control directly from the arduino (pin 9)? If so I imagine orange (power) pin of the control module would go to the transistor?

I wanted to use say pin 10 to turn on or off the servo, and pin 9 as the PWM control pin to control servo direction and speed.

This is what I am envisioning (attached schematic).

Is there an easier way to accomplish this? Any information or advice is greatly appreciated.

-Matt


Magician

Have a link to servo data sheet? Why do you think you need to disconnect power line, save a battery? 

08yamaha600

http://www.philohome.com/motors/motorcomp.htm


I have:
-2x - 5292's
-2x - 47154

I am most likely going to stick with the 47154's because of they consume a fraction of the amount of current - and the amount of power I need them dissipate is minimal.

I am using a VEX 3-pin servo control module (http://www.vexrobotics.com/276-2162.html) to control the servo's. The schematic i posted previously does NOT work as described. I am going to try common emitter.

The point was to remove the stress of powering the servos off of the arduino and power them using a battery or other supply.

Magician

Just to clear, so you hack a servo and replace a motor? Control module isn't continuous rotation .

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy