Most assembly plants nowadays rely heavily on robotic arms in assembling their products. These electro-mechanical machines has replaced humans in many factories because of its many advantages. Among them, are its effeciency, productivity, reliability and immunity to human factors and natural behaviours. They can work mostly round the clock at 24/7 mode without stress or fatigue. They are programmable and able to perform multi-tasking jobs.  The only drawback is the downtime during maintenance period and when some electronic circuits, electrical wirings and mechanical parts failed to function or damaged. Robotic arms can work autonomously or with minimum human intervention depending on its configuration. There are more advanced design capable to function with very high precission and accuracy.

A Toy Robotic Arm as shown or similar is available in some stores or on the internet. This Toy Robotic Arm is the basic principle and can perform some of the basic functions or movements compare to the more sophisticated industrial type which can be programmed and perform various tasks. This basic robotic arm only utilized several DC motors and basic mechanical parts to operate powered by batteries.

However, this Toy Robotic Arm can be modified to work as programmable or function autonomously without continued human intervention.

TOY ROBOTIC ARM

The idea here now is to modify this Toy Robotic Arm  so it will work like the basic industrial type with autonomous mode instead of operating it through the switches connected to it. Once modified It can be programmed to do some basic tasks repeatedly several times and work autonomously.  Actually, you just need to press a key  or some keys on your keyboard depending on what function you want it to initiate once you learn how to program it. 

So, with the help of some materials listed below and modification guides, this Toy Robotic Arm will function like the basic industrial type.

WHAT YOU NEED:

1. Raspberry Pi Computer Board - any model

2. SD Card                                         - with RISCOS, BBC BASIC and GPIO Module 

                                                                 Download GPIO Module here:                                                                                                                          http://tankstage.co.uk/software.html

3. 5.0 Volts DC Power Supply        - for Raspberry Pi

4. 12 Volts DC Power Supply         - for Relay board

5. Relay Board                                  - available from this website

6. Side Cutter

7. Long nose plier

8. Heatshrink tube     

9. Soldering Iron

10. Soldering lead

11. Diode  Rectifier   (2pcs)  - any diode rated at  50V / 1A  or better, Ex. 1N4001

12. D-Type Connector pins

13. Wires - #22 or 24 AWG

BASIC INTERNAL ELECTRICAL DIAGRAM



MODIFICATION INSTRUCTION:

1. Cut-off the Remote Controller Switch and mark or label the white  ribbon cable as shown.

2. Solder a female 'D' Type Connector pin on each wire and insulate with a heatshrink tube as            shown.

    WIRE FUNCTION IDENTIFICATION                                   CORRESPONDING RELAY

A  -  B+ SUPPLY  ---------------------------------  GPIO 4  ----------------------- A

B  -  B-  SUPPLY ---------------------------------- GPIO 17  ---------------------- B

C  -  BASE  MOTOR------------------------------  GPIO 27  ---------------------- C

D  -  SHOULDER  MOTOR---------------------  GPIO 22  ---------------------- D

E  -  ELBOW MOTOR----------------------------- GPIO 10  ---------------------- E

F  -  WRIST  MOTOR------------------------------  GPIO 9  ------------------------ F

G  - CLAMP MOTOR------------------------------ GPIO 11  ---------------------- G

H  - LAMP  ------------------------------------------ GPIO 7  ------------------------ H

RELAY ASSIGNMENT

DUAL POLARITY GROUNDING POINT

NOTE: 

1. THE RELAY A TO H ARE DPDT TYPE. SO, YOU CAN USE EITHER OF THE SWITCH OR      

     PARALLEL IT USING JUMPER WIRE.

2. DIODES A & B ARE BLOCKING DIODES TO PREVENT SHORTING WHEN THE POLARITY OF

     THE GROUNDING TERMINAL CHANGES FROM POSITIVE TO NEGATIVE AND VICE VERSA

     DURING FUNCTION SWITCHING.

 ALL MOTORS CONNECTION

TERMINATION OF WHITE RIBBON CABLE TO RELAY BOARD

3.  Insert a 'D' Type Connector male pin on the relay terminal holes of the Relay Board and                  solder. Cut-off excess length of the pins. Note that two pins are needed for each relay.

4. Cut a small strip of raw circuit board or copper plate or wire to be use as Ground Terminal.

5. Fasten the Ground Terminal on the middle part of the Relay Board as shown.

6. Cut eight  pieces of about 8 cm length of  #22 AWG wire.

6. Solder a female pin on one end of each wire and insulate with heatshrink tube.

7. Plug-in the wires to the Relay Board terminal pins as shown (Green Wires).

8. Solder the other end of each wire except A and B  to the Grounding Teminal fastened on Relay      Board. 

9. Solder the Anode side of the diode to the other end of Green wire A.

10. Solder the Cathode side of the diode to the other end of Green wire B.

11. Solder the other end of diodes A and B to the Grounding Teminal.

12. Plug-in the Robotic Arm white ribbon cable wires to the corresponding relay terminal pins.

13. Plug-in the ribbon cable or connect the jumper wires to Raspberry Pi  P1 terminal pins and             connect the other end to the Relay Board input terminal according to wiring identification                 connection as shown above.

 14. Highlight the program code below using your mouse or touch pad and 'right click' to copy to           Notepad or any text editor. Transfer the code to the BBC BASIC Programming Language                 StrongEd window text editor and SAVE as BASIC file.

15. Run and see if the menu as shown below show-up on your monitor.

THE PROGRAM MENU

NOTE:

Just contact or email me should there be any problem regarding this project or experiment.

HOW IT WORKS VIDEO

https://www.youtube.com/watch?v=nNTYAzqSk7E

 THE PROGRAM CODE

   10 MODE 20: GCOL 3: OFF

   20 COLOUR 26: PRINT TAB(1,10); "Press Key to activate:"

   30 COLOUR 7

   40 PRINT TAB(1,16); "> OR UP= TO SWITCH B+ SUPPLY": REM GPIO 4

   50 PRINT TAB(1,18); "< OR DOWN= TO SWITCH B- SUPPLY": REM GPIO 17

   60 PRINT TAB(1,20); "B= TOMOVEBASE       ": REM GPIO 27

   70 PRINT TAB(1,22); "S= TOMOVESHOULDER   ": REM GPIO 22

   80 PRINT TAB(1,24); "E= TOMOVEELBOW      ": REM GPIO 10

   90 PRINT TAB(1,26); "W= TOMOVEWRIST      ": REM GPIO 9

   90 PRINT TAB(1,28); "C= TOMOVECLAMP      ": REM GPIO 11

  100 PRINT TAB(1,30); "T= FUNCTIONAL CHECK   "

  110 PRINT TAB(1,32); "SPACEBAR= RESET       "

  120 COLOUR 18: PRINT TAB(1,1); "Raspberry Pi Robotic Arm"

  130

  140 COLOUR 12: PRINT TAB(36,1); "BUILT & PROGRAMMED BY: Rolly Estomaguio"

  150

  160 REM Programmed on: 12 May 2014 - Updated 04 July 2015

  170

  180 COLOUR 31: PRINT TAB(42,3); "http://www.kits-gadgets.com"

  190

  200 ON ERROR PRINT REPORT$;" at line ";ERL:END

  210 PROCinit

  220 COLOUR 10: PRINT TAB(1,50); "Press Escape to finish"

  230 PROC_switch

  240

  250 DEFPROCinit

  260 OSCLI"RMEnsure GPIO 0.00 RMLoad GPIO"

  270 OSCLI"RMensure GPIO 0.40 ERROR Please install the GPIO module"

  280 SYS"GPIO_EnableI2C",0

  290 SYS"GPIO_ExpAsGPIO",2

  300 SYS"GPIO_GetBoard" TO PiType%

  310  DIM A%(17)

  320 IF PiType%=12 A%()= 3,4,17,27,22,10,9,11,7,8,25,23,15,14,24,2

  330 ENDPROC

  340

  350 DEFPROC_switch

  360 L$=GET$: OFF

  370 IF L$= "B" OR L$= "b" PROC_base

  380 IF L$= "S" OR L$= "s" PROC_shoulder

  390 IF L$= "E" OR L$= "e" PROC_elbow

  400 IF L$= "W" OR L$= "w" PROC_wrist

  410 IF L$= "C" OR L$= "c" PROC_clamp

  420 IF L$= "Q" OR L$= "q" QUIT

  430 IF L$= "T" OR L$= "t" PROC_robotarm

  450 PROC_switch

  460

  470 DEFPROC_robotarm

  480 REM THIS SUBROUTINE IS TO TEST ALL  MOVEMENTS AUTONOMOUSLY

  490 SYS "GPIO_WriteData",4,1: REM B+ ON

  500 SYS "GPIO_WriteData",27,1: REM BASE ON

  510 FOR D= 1 TO 38E6:NEXT

  520 SYS "GPIO_WriteData",4,0: REM B+ OFF

  530 SYS "GPIO_WriteData",27,0: REM BASE OFF

  540 FOR D= 1 TO 1E6:NEXT

  550 SYS "GPIO_WriteData",17,1: REM B- ON

  560SYS "GPIO_WriteData",22,1: REM SHOULDER ON

  570 FOR D= 1 TO 10E6:NEXT

  580 SYS "GPIO_WriteData",17,0: REM B- OFF

  590 SYS "GPIO_WriteData",22,0: REM SHOULDER OFF

  600 FOR D = 1 TO 1E6:NEXT

  610 SYS "GPIO_WriteData",17,1: REM B- ON

  620 SYS "GPIO_WriteData",9,1: REM WRIST ON

  630 FOR D= 1 TO 13E6:NEXT

  640 SYS "GPIO_WriteData",17,0: REM B- OFF

  650 SYS "GPIO_WriteData",9,0: REM WRIST OFF

  660 FOR D= 1 TO 1E6:NEXT

  670 SYS "GPIO_WriteData",4,1: REM B+ ON

  680 SYS "GPIO_WriteData",11,1: REM CLAMP ON - CLOSE

  690FOR D= 1 TO 7E6:NEXT

  700 SYS "GPIO_WriteData",4,0: REM B+ OFF

  710 SYS "GPIO_WriteData",11,0: REM CLAMP OFF

  720 FOR D= 1 TO 1E6:NEXT

  730 SYS "GPIO_WriteData",4,1: REM B+ ON

  740 SYS "GPIO_WriteData",9,1: REM WRIST ON

  750 FOR D= 1 TO 13E6:NEXT

  760 SYS "GPIO_WriteData",4,0: REM B+ OFF

  770 SYS "GPIO_WriteData",9,0: REM WRIST OFF

  780 FOR D= 1 TO 1E6:NEXT

  790 SYS "GPIO_WriteData",4,1: REM B+ ON

  800 SYS "GPIO_WriteData",22,1: REM SHOULDER ON

  810 FOR D= 1 TO 13E6:NEXT

  820 SYS "GPIO_WriteData",4,0: REM B+ OFF

  830 SYS "GPIO_WriteData",22,0: REM SHOULDER OFF

  840 FOR D = 1 TO 1E6:NEXT

  850 SYS "GPIO_WriteData",17,1: REM B- ON

  860 SYS "GPIO_WriteData",27,1: REM WAIST ON

  870 FOR D= 1 TO 38E6:NEXT

  880 SYS "GPIO_WriteData",17,0: REM B-OFF

  890 SYS "GPIO_WriteData",27,0: REM WAIST OFF

  900 SYS "GPIO_WriteData",17,1: REM B- ON

  910 SYS "GPIO_WriteData",11,1: REM CLAMP ON - OPEN

  920 FOR D= 1 TO 5E6:NEXT

  930 SYS "GPIO_WriteData",17,0: REM B- OFF

  940 SYS "GPIO_WriteData",11,0: REM CLAMP OFF

  950 FOR D= 1 TO 15E6:NEXT

  960 K%= INKEY (0.6)

  970 IF INKEY (-99) THEN PROC_switch

  980 PROC_robotarm

  990

 1000 DEFPROC_base

 1010 OFF

 1020 SYS "GPIO_WriteData",27,1

 1030 REPEAT

 1040 K%= INKEY (.5)

 1050 IF INKEY (-99) SYS "GPIO_WriteData",27,0: PROC_switch

 1060 IF INKEY (-122) THEN SYS "GPIO_WriteData",17,1: SYS "GPIO_WriteData",4,0: REM CW ROTATE

 1070 IF INKEY (-26) THEN SYS "GPIO_WriteData",4,1: SYS "GPIO_WriteData",17,0: REM CCW ROTATE

 1080  FOR D%  = 1 TO 2000000:NEXT

 1090 SYS "GPIO_WriteData",17,0: SYS "GPIO_WriteData",4,0

 1100 PROC_base

 1110

 1120 DEFPROC_shoulder

 1130 SYS "GPIO_WriteData",22,1

 1140 REPEAT

 1150 L%= INKEY (.5)

 1160 IF INKEY (-99) SYS "GPIO_WriteData",22,0: PROC_switch

 1170 IF INKEY (-58) SYS "GPIO_WriteData",17,1: SYS "GPIO_WriteData",4,0

 1180 IF INKEY (-42) SYS "GPIO_WriteData",4,1: SYS "GPIO_WriteData",17,0

 1190 FOR D%= 1 TO 2000000:NEXT

 1200 SYS "GPIO_WriteData",17,0: SYS "GPIO_WriteData",4,0

 1210 PROC_shoulder

 1220

 1230 DEFPROC_elbow

 1240 SYS "GPIO_WriteData",10,1

 1250 REPEAT

 1260 M%= INKEY (.5)

 1270 IF INKEY (-99) SYS "GPIO_WriteData",10,0: PROC_switch

 1280 IF INKEY (-58) SYS "GPIO_WriteData",17,1: SYS "GPIO_WriteData",4,0

 1290 IF INKEY (-42) SYS "GPIO_WriteData",4,1: SYS "GPIO_WriteData",17,0

 1300 FOR D%= 1 TO 2000000:NEXT

 1310 SYS "GPIO_WriteData",17,0: SYS "GPIO_WriteData",4,0

 1320 PROC_elbow

 1330

 1340 DEFPROC_wrist

 1350 SYS "GPIO_WriteData",9,1

 1360 REPEAT

 1370 N%= INKEY (.5)

 1380 IF INKEY (-99) SYS "GPIO_WriteData",9,0: PROC_switch

 1390 IF INKEY (-58) SYS "GPIO_WriteData",17,1: SYS "GPIO_WriteData",4,0

 1400 IF INKEY (-42) SYS "GPIO_WriteData",4,1: SYS "GPIO_WriteData",17,0

 1410 FOR D%= 1 TO 2000000:NEXT

 1420 SYS "GPIO_WriteData",17,0: SYS "GPIO_WriteData",4,0

 1430 PROC_wrist

 1440

 1450 DEFPROC_clamp

 1460 SYS "GPIO_WriteData",11,1

 1470 REPEAT

 1480 O%= INKEY (.5)

 1490 IF INKEY (-99) SYS "GPIO_WriteData",11,0: PROC_switch

 1500 IF INKEY (-122) SYS "GPIO_WriteData",17,1: SYS "GPIO_WriteData",4,0

 1510 IF INKEY (-26) SYS "GPIO_WriteData",4,1: SYS "GPIO_WriteData",17,0

 1520 FOR D%= 1 TO 2000000:NEXT

 1530 SYS "GPIO_WriteData",17,0: SYS "GPIO_WriteData",4,0

 1540 PROC_clamp

NOTE:

The above program is not final and has several unnecessary commands and line numbers. Feel free to modify if necessary. Nevertheless, it works fine without modification.

NEXT ON THIS PROJECT:

1. Installation of end limit switches.

2. Upgrading the program code.

REMINDERS:

The author, publisher or provider of the above information does not and will not provide any guarantee that all information stated herein are free of errors.

Any attempt to exercise, simulate or initiate to follow the above information are at the sole discretion and risk of the one building the project and owner of the devices, gadgets and materials required to build.

The same condition applies if any failure, fault and damage occured during or while performing and following the given instructions for the purpose of experimentation, curiosity and as a building hobby.

However, the author of the above information made sure that the prototype, simulation and preliminary project and ideas above are working and performing according to the desired results and functions before its publication.

Additionally, any project, kits and gadgets published on this website have undergone rigorous tests and simulation.