C1-10P Head Arm Mechanism

Read First!

Credit to TinyP for his C1-10P dome design which this design is based around.

This is a head arm mechanism design for C1-10P droids, Chopper from Star Wars Rebels.

Some of the parts like the link will need 100% infill due to its miniature size, and others can be decided on when you print, some other components like fasteners will need to be sourced to assemble.

I have about 40-50 hours of design and build work put into this to get it to a stage of version 1 ready for release.

This design enables wrist posing, pincer posing, elbow rotation 90° and shoulder rotation 180°.

2 Servos are needed for the wrist and shoulder.

The small servo link is made with 1.6mm diameter steel rod.

Print the pincers, forearm and wrist joint with 3-4 shell layers and 10% infill to keep the weight down.

The 3 first stage components should be about 50% infill or more for strength, but light enough to keep the weight down for the main servo life and sag/ hanging reduction on the system.

Hardware (not an exhaustive list) this is a DIY:

Nuts and bolts, M4, M3, etc, screws various for screwing into timber dowel

Servo horn round to suit large servo HS 225 or similar

1 off Servo HS 225 MG (various sources)

https://www.servocity.com/hs-225mg

1 off 9gram servo (get a metal gear if you like)

https://www.banggood.com/3PcsPack-KittenBot-23x12_2x29mm-SG90-9g-Mini-Servo-with-25cm-Wire-for-Smart-Robot-Car-p-1347733.html?rmmds=search&cur_warehouse=CN

1.6mm wire, something strong for the servo forearm linkage.(Hobby shop rc plane linkages)

2 off x 8mm Timber dowel x 320mm long (hardware store, can be 8mm aluminium rod)

5 or 6mm dowel for the idler pulley, can be a cut off bolt or anything the correct diameter

6mm wide 3D Printer belt

https://www.banggood.com/5M-2GT-6mm-Rubber-Opening-Belt-S2M-GT2-Belt-For-3D-Printer-p-959254.html?rmmds=search&cur_warehouse=CN)

Gt2 Belt toothed pulley to attach to DC motor, choose pulley ID to suit motor shaft

https://www.banggood.com/162030T-GT2-Aluminum-Timing-Drive-Pulley-For-DIY-3D-Printer-p-1001266.html?rmmds=search&ID=516464&cur_warehouse=CN)

1 off DC motor (NOTE: I've tried the motor at 6V power and it is fine, can be boosted to 9-10V for faster motion)

https://www.banggood.com/DC-3V-6V-DC-1120-Gear-Motor-TT-Motor-for-Arduino-Smart-Car-Robot-DIY-p-1260117.html?rmmds=search&cur_warehouse=CN

Limit switches 2 off for end stops (2 each arm if you are making 2 arms)

https://www.banggood.com/10Pcs-Micro-Limit-Switch-Roller-Lever-5A-125V-Open-Close-Switch-p-945733.html?rmmds=cart_middle_products&cur_warehouse=CN

Servo horn connectors for the forearm linkage

https://www.banggood.com/1_3mm-1_8mm-2_1mm-Adjustable-Pushrod-Connectors-Linkage-Stoppers-For-RC-Airplane-p-1118874.html?rmmds=search&ID=517040&cur_warehouse=CN

This design may change if I find any major issues with it during its usage, at this point in time, November 2018, it hasn't been fully road tested with long term use in a droid.

The DC motor has not been tested as I haven't purchased one yet, this would only effect one printed component though, the Motor Mount. So if it is amended later I will up revision the model and the recommended motor that I use.

Hope it helps those wanting to add hands and movement to their C1-10P droid.

Happy Building!

Matt