Small Robot Gripper

Assembly of Small Robot Gripper

This document describes the development of Cytron Technologies’ hardware- Small Robot Gripper. This document will teach you how to assemble the Gripper and the servo. Circuit schematic diagram and sample PIC source code are provided. The source code provides a simple gripper open-close program and servo position calibrating function.


Basic Circuit

–          PIC16F877A – SK40C

–          8 Channel Servo Controller – SC08A

–          Digital RC servo included in Small Robotic Gripper

SC08A Servo Controller

–    Provides 8 control channels

–    Simple communication protocol with UART


This project will require the following hardware:

a)      1 x PIC16F877A

b)      1 x Robotic Gripper

c)      1 x Digital RC servo

d)     1 x SC08A

e)      1 x SK40C (Enhanced 40 pins PIC Start-Up Kit)

f)       1 x UIC00B (USB ICSP PIC Programmer V2010)

g)      Related hardware components

h)      Related electronic components

Connecting SC08A to Microcontroller and Servo Motor


Figure 1    

                                                                            Figure 2

This is the Small Robotic Gripper that we are going to used. Figure 1 shows the front view of the gripper while figure 2 shows the back view of the gripper.

How to Built the Robot Gripper

Figure 3 shows the Robot Gripper pack that we get from Cytron Technologies, and we need to choose the parts that we are going used as shown in figure 4.

Figure 3  

                                                                                                 Figure 4

Before we starts to built the Gripper, we need to know the maximum and minimun extension of the gripper so that we can program our servo’s movement properly without damaging the servo’s gear. Figure 5 and 6 shows the maximum extension of the gripper while figure 7 and 8 shows the minimum extension of the gripper.

                          Figure 5                                                                                                                    Figure 6

                            Figure 7                                                                                                                Figure 8

To begin the installation of the gripper, we need to connect the servo horn with the gripper as shown in figure 9-13 below.

                          Figure 9                                                                                                                    Figure 10

For figure 10, we need to find the best hole that suits between the gripper and the servo horn. May be the hole of the horn is not really suits for the gripper, but can be joint together as shown in figure 11 till figure 13.

  Figure 11                                                                                                                                  Figure 12

Figure 13

After joining the horn, we need to program the moving position of the servo so that it move without crashing the side of the gripper as shown in figure 14 below. But how do we measure it? We can use the other servo horn in the package to measure the angle of rotation of the servo as shown in figure 15. Remember: try not to exceed the limit angle of the gripper, else u’ll damage the internal gear of the servo motor.

Figure 14                                                                                                      Figure 15

Before we proceed to the next step, do you know how the servo is communicate with the servo controller (SC08A)? And how the PIC16F877A communicate with SC08A? It is just some simple steps as shown in figures below. Beware the polarity of the connector of the SC08A and the PIC16F877A as shown in figure 16. Create the connector cable according to the order as shown in figure 18. The first 2 nodes which are crossed are RX and TX pins. For UART communication between 2 MCUs, the RX pin of one MCU is connected to TX pin of another MCU.

Figure 16                                                                                                                           Figure 17

                   Figure 18                                                                                                                    Figure 19

Next, we need to connect the servo motor to the gripper. Screw up the servo with the gripper using PCB stands as shown in figure 20. Remember to lock the other side of the servo as shown in the figure 21.

                                      Figure 20                                                                                         Figure 21

Then we connect the servo horn to the servo motor as shown in figure 22.

Figure 22

That’s it… Figure 23 shows the final product of the small robot gripper.

Figure 23

The Sample Source Code (c and hex) of the servo motor are provided in the Cytron’s website.

Sample code

The video of the Small Robot Gripper can be watched from Youtube.



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