RobotGeek Gripper Getting Started Guide

This page has some tips for working with the Robot Geek Gripper.

This guide will refer to the RobotGeek Geekduino, the microcontroller that will ship with most RoboTurrets. However this kit will also work with the Arduino Uno, or other Arduino variants like the Seeeduino.

Setting up the Arduino Software

If you have not already set up your Geekduino/ Arduino compatible board, please see the Geekduino Getting Started Guide. This guide will assist you in getting set up with the Arduino software as well as install libraries and test sketches for RobotGeek Robots.

Configuring Your Servos

Servos can be set to specific positions using the Geekduino board. It is important that your servos are correctly set to the correct position before you start assembly, or your robot will not work properly.

If you are going on to build the RobotGeek Snapper Arm then you can also configure your other arm servos in this step.

First you will need to attach your RobotGeek Sensor Shield to your Geekduino.

Next you will need to set the power jumpers for the servos. Set both power jumpers to VIN

Connect the two servos to the RobotGeek Sensor Shield as shown in the diagram below. If you are going on to build the RobotGeek Snapper Arm, then also plug in the 3 additional RobotGeek Servos as shown in the last diagram.

Now connect the external power supply to the Geekduino.

Device Pin
Gripper Servo (9g Blue Mirco Servo) 10
Wrist Servo (RobotGeek Servo) 9
Base Servo (RobotGeek Servo) 3
Shoulder Servo (RobotGeek Servo) 5
Elbow Servo (RobotGeek Servo) 6
b_400_400_16777215_00__images_tutorials_rgGripper_gripperOnly.png
Wiring for Gripper Servo Only
b_400_400_16777215_00__images_tutorials_rgGripper_gripperWithWrist.png
Wiring for Gripper and Wrist Servo
b_400_400_16777215_00__images_tutorials_rgSnapperArm_snapperArmServosOnly.png
Wiring for Snapper Arm

For assembly in the gripper, you will need to set the 9G servo to 150° and the RobotGeek Servos to 90°. The following sketch will set the servos correctly.

File -> Sketchbook -> RobotGeek Sketches -> Tools -> gripperAndArmServos

Once the RobotGeek servos are centered you can install the servo horn with the notch pointing straight up, and install the black screw. The screw will cover the notch, but lining the knotch straight up will ensure that the horn is set at the correct angle.

b_400_400_16777215_00__images_tutorials_rgServo_180horn1.jpg b_400_400_16777215_00__images_tutorials_rgServo_180horn2.jpg b_400_400_16777215_00__images_tutorials_rgServo_180horn3.jpg

The Wrist Servo for the gripper will also require a idler horn. Install the idler horn on the back of the servo and secure it with the silver screw. If you are going on to build the RobotGeek Snapper Arm, install idlers on 2 more servos, leaving the last servo with no idler horn.

b_400_400_16777215_00__images_tutorials_rgServo_idlerhorn0.jpg b_400_400_16777215_00__images_tutorials_rgServo_idlerhorn1.jpg b_400_400_16777215_00__images_tutorials_rgServo_idlerhorn2.jpg

No horn will be installed on the 9G servo at this time

See this page for more information and a video on centering servos.

Assembly Guide

RobotGeek Gripper Assmebly Guide

Testing the Gripper

To test the gripper, first connect the servos just like in the Servo Configuration step.

Device Pin
Blue Mirco Servo (Gripper) 9
Black Large Servo (Wrist) 11
b_400_400_16777215_00_images_tutorials_rgGripper_rgGripperServoSetup.png

Now load the gripperAuto sketch onto the Geekduino.

File -> Sketchbook -> RobotGeek Sketches -> Test -> gripperAuto

The sketch will automatically repeat the following sequence:

  • Open gripper, wait 3 seconds
  • Close Gripper, wait 3 seconds
  • Lower Wrist Servo ~ 90 degrees, wait 3 seconds
  • Raise Wrist Servo ~ 90 degrees, wait 3 seconds
  • Level Wrist Servo, wait 3 seconds

If the gripper does not follow this sequence, then please check that it is assembled correctly.

Controlling the Gripper

This configruation will allow you to control the gripper using 2 Analog Sensors. This example will work with any analog sensor - this example will use RobotGeek Rotary Knobs.

Device Pin
Blue Mirco Servo (Gripper) Digital 9
Black Large Servo (Wrist) Digital 11
Knob 1 (Controls Gripper) Analog 0
Knob 2 (Controls Wrist) Analog 1
b_400_400_16777215_00_images_tutorials_rgGripper_rgGripperServoSetupKnob.png

Now load the gripperKnob sketch onto the Geekduino.

File -> Sketchbook -> RobotGeek Sketches -> Test -> gripperKnob

By turning the knobs you can control the positions of the two servos.

These servos have no over-current protection. Trying to lift to large of a load or applying to much force to the gripper may damage the servos.