Week 5 Journal Entry – TowerPro SG92R Micro servo

sg92r-high-torque-micro-servo-800x800

The TowerPro SG92R is a small and lightweight servo motor that can rotate approximately 180 degrees (90 in each direction). It has carbon fiber gears and control arms resulting in 2.5kg torque, with just 9g of weight. Because everything is small and made of plastic, this servo is not nearly as strong as a standard one. However, it is very popular among hobbyists, because of its price ($5.95) and small dimensions. Also, it can be used with any hardware, such as the Arduino Motor Shield or Adafruit’s 16 Channel Servo Driver, as well as any servo code or special Servo Library, that supports up to 12 motors on most Arduino boards.

The unit comes with 25cm wire and 3-pin ‘S’ style female header connector that fits most receivers. Like any other servo, the SG92R has three wires: power, ground and signal. The power wire is red, and should be connected to the 5V pin on the Arduino. The ground wire is brown and goes to a ground pin. The signal wire is orange, and should be connected to a digital pin on the Arduino (pins 9 or 10 are recommended):

servo_curcuit1

The position of the servo is set by the length of a pulse. Position “0”(1.5ms pulse) is middle, “90”(~2ms pulse) is all the way to the right, “-90″(~1ms pulse) is all the way to the left.

servos

 

The fastest way to understand how a servo works, is to hook it up to an Arduino and run a standard Sweep sketch that one can find in the Arduino Examples under the folder Servo.

TowerPro SG92R Specifications

SG92R in action

Inside a Servo Motor

Available from these sellers:

adafruit.com

headsuphobby.com

dx.com

 

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