The Handy Helper

Robotic hands are widely used in industry and other specific applications. As robotics evolved, machines started to become more complex and perform more tasks. The robotic hand that we designed is easily programmable with an Arduino Uno and has the capabilities to perform various tasks. However, the primary purpose of this project was to perform sign language with a voice recognition module.

For this project, you will need

• The CAD files for the 3-D printed hand parts
• 12 motors (7 metal geared servos (MG90S) / 5 plastic geared servos (SG90))
• pan and tilt kit (SPT200H from servo city)
• screws/ bolts with washers and nuts
• Arduino Uno Kit
• PLA

Once the CAD files are downloaded, you will then need to use PLA to print them. The parts will be ported to SolidWorks and then transferred to the 3-D printer. The fingers for the hand will also be printed on the 3D printer with PLA filament.

Once all parts are printed, there will be extra PLA attached to the parts that aid the printer during the printing process. Remove the scaffolding and file down the rough edges.

All fingers will be printed in three sections with three joint sections and two printed motor arms. Once all sections and pieces are printed, assemble with allotted screws. Lastly, place servos into each slot and screw them down. The gray servos will be used for the lower knuckles while blue servos will be used for the upper. Be careful not to pinch wires in this process.

Assemble knuckles of thumbs just as the fingers were assembled. Connect the base of the thumb by sliding the "C" shaped join around the tube of the thumb base then securing it in place with the allotted screws. Lastly, place servos into each slot and screw them down. The gray servos will be used for the lower knuckles while blue servos will be used for the upper. Be careful not to pinch wires in this process.

Make sure motors are pressed firmly into the designated slot. Then attach the printed arm that attaches the motor to the base of the finger. Once this is complete, screw motor in with allotted screws to ensure stability and performance.

When attaching fingers to the hand be sure that the motors are all installed in the correct direction. Then, make sure that all of the wiring is out of the way and is run down through the wrist in the correct position (see photos). Finally, attach fingers firmly with allotted screws.

To attach the index finger, slide the two small tubes in the finger around the large tube located on the hand, then secure with allotted screws. Note: space in the bottom of the index finger may need to be drilled out in order to accommodate the bolt heads.

To attach the thumb, tilt the index finger out of the way and place blots through the top of the hand and into the thumbs base. Then secure the bolts with nuts from the inside of the hand.

For the thumb, attach the printed arm that attaches the motor to the base of the thumb. For the index finger, use the wood screw and the metal rod to attach the IB motor to the back of the finger.

Once the hand is fully assembled, slide wires through the base of the hand and through the large hole of the pan and tilt plate

Assemble pan and tilt using instructions provided by the manufacturer.

To attach the pan and tilt guard to the hand, first, run wires through the open slot of the guard. Then, place the guard over the top pan and tilt motor. Be sure that the guard is placed so that the bottom sits flush with the pan and lilt.

Run 4 bolts through the top pan and tilt and then through the pan and tilt plate at the base of the hand. Make the nuts snug but not tight enough to crack the PLA.

The stand is a 5 sided wooden box that can be made out of a wood of choice. The hand need s to sit roughly 2/3 of the way towards the back of the stand in order to maintain the correct balance. There will also be a hole cut in the side and in the top for correct wire placement. Sand and stain the stand to preference.

Drill the correct sized hole for the allotted bolts and nuts. Run all 4 bolts through the base of the pan and tilt. Then run them through the holes drilled in the base. Tighten down firmly on the underside of the base. Don't forget the wiring needs to be run through a hole centered between the smaller holes for the bolts.

Once the hand is completely assembled, then begin the wiring process. The wiring to the Arduino should mainly deal with the 13 motors that were introduced earlier. This step is very intricate and should be done carefully. We found the use of a label maker very helpful in the wiring process as it helped us distinguish what goes where once everything was installed and ready to be plugged up to the Arduino Uno.

Once the box is completed with all required sanding, staining, drilling of holes, and attaching of the hand is completed, mount the electronics neatly on the inside of the box with 3M sticky Velcro cut to size.

After everything is connected to the Arduino with wires, the coding process is ready to begin. The code illustrated here is derived from a previous senior design project and along with the department head's coding. Trial and error are done at this step, therefore, this will be the longest step.

For the final step in creating the robotic hand, ensure all coding is done correctly. The wiring for the hand will need to be hidden away to keep everything safe. The hand will function properly at this step if all preceding steps are done correctly.