Get Help
Basic Gripper Usage
Introduction
Sparki has a gripper. It will be useful to learn how to use it before we move to more complex tasks. And of course, we will use the gripper in future lessons.
The gripper is a simple mechanism driven by a stepper motor, the same kind of motor used to move Sparki’s wheels. The stepper motor’s shaft has a pinion attached, which drives a rack:
Thus, moving the motor in one direction opens the gripper, while moving the motor in the other direction closes it.
Programming the Gripper
Having learned this, we are now going to program the gripper’s movements.
Please remember to check that the batteries are properly connected (and charged!). And as we are going to use the motors here, please check that the On/Off Switch is on. Another important thing to take care of when playing with the robot’s motors is to be careful not to be working over a table. A fall from that table could permanently damage your Sparki.
The basic commands that Sparki’s software provides to control the gripper are:
|
1 2 3 |
sparki.gripperOpen(); // opens the grippers sparki.gripperClose(); // closes the grippers sparki.gripperStop(); // stops the gripper from moving |
Be careful if you find that the gripper is in one of the positions shown in the previous image, since trying to move it during long intervals of time when it’s blocked may damage the motor. For example, if the gripper is closed (as shown in the left photo), you should try first to open it a bit with a simple program like this:
|
1 2 3 4 5 6 7 8 9 10 11 12 |
#include <Sparki.h> // include the sparki library void setup() { sparki.gripperOpen(); // open the robot's gripper delay(1500); // for 1.5 seconds (1500 milliseconds) sparki.gripperStop(); } void loop() { } |
|
1 2 3 4 5 6 7 8 9 10 11 12 |
#include <Sparki.h> // include the sparki library void setup() { sparki.gripperClose(); // close the robot's gripper delay(1500); // for 1.5 seconds (1500 milliseconds) sparki.gripperStop(); } void loop() { } |
Now, try making small modifications to the time interval. For example, you can open (or close) it for 2 seconds. Please don’t try big numbers here, since you will reach the gripper’s mechanical limit fast. By making a few little experiments with the intervals of time, you will soon be familiarized with the gripper’s limits.
Finally, you can try the example program included with the SparkiDuino software. Please go to the menu File->Examples->Gripper and download the code to your Sparki:
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 |
/******************************************* Basic Gripper test Sparki has two little grippers it can be used to grab objects and drag them around. See what you can grab with them! ********************************************/ #include <Sparki.h> // include the robot library void setup() { } void loop() { sparki.gripperOpen(); // open the robot's gripper delay(1000); // for 1 second (1000 milliseconds) sparki.gripperClose(); // close the robot's gripper delay(1000); // for 1 second (1000 milliseconds) sparki.gripperStop(); // stop the grippers from moving delay(1000); // for 1 second (1000 milliseconds) } |
This small program will open and close your Sparki’s gripper in a never-ending loop, opening it for 1 second (1000 milliseconds), closing it for 1 second, then pausing for 1 second:
Extra Activities
If you want to improve the control of the gripper, you can always use the stepper motor instructions that we have learned before:|
1 2 |
sparki.motorRotate(int motor, int direction, int speed); sparki.motorStop(int motor); |
Lesson available for the miniBloq Programming Environment
This lesson is also available for the miniBloq Programming Environment. miniBloq is a graphical programming environment that you can use to easily program your Sparki.
