Return to the BUILD

“This issue’s parts include the final section and connectors you need to make the third ring frame inside R2-D2’s body, which is fitted just under his dome. You also have two electronic sensors that are used to monitor the position of his head.”

The Droid Directory section of the magazine is gone, which means there is going to be a lot to do. Two in a row again!



Materials: The ring parts are metal, the Sensor Mounts are plastic, and the Centre Stop is hard rubber.


  • Building The Galaxy – Building the Galaxy
  • Understanding Robotics – 5G Networks
  • Build R2-D2: Model Instructions


Assembling the Top Ring

Step 1

Retrieve the Top Ring assembly we started back in Issue 81 and arrange it with this issue’s parts, as shown:

Steps 2-6

As has been completed many times before, align the dovetail joints and attach a Ring Connector under them. Secure both ends of the joints with one (1) 2×4 mm silver screw. Repeat this on the other joint as well using a total of four (4) 2×4 mm silver screws, as shown:

Make sure these Ring Connectors are all on the same side of the completed ring, as shown:

Fitting the Rotary Sensors

Steps 1-4

Plug the smaller plug of each Sensor Cable into the matching Left Rotary Sensor and Right Rotary Sensor sockets, as shown:

Steps 5-7

Align a Sensor Mount with the matching holes in the black plastic of the Right Rotary Sensor as shown:

Steps 8-9

Secure the Sensor Mount to the sensor using two (2) 2.3×6 mm black screws, as shown:

Step 10

Repeat the previous steps with the other Sensor Mount and the Left Rotary Sensor:

Steps 11-15

Align the Left Rotary Sensor assembly to the Top Ring assembly as shown, and secure it to the ring with two (2) 2.3×6 mm black screws:

Steps 16-17

Repeat this process with the Right Rotary Sensor assembly:

Steps 18-21

Slide the Centre Stop over the tab between the sensors, align the hole, then secure it with one (1) 2.5×6 mm flanged silver screw.

We are going to replace this Centre Stop with a better one in Issue 98:

Assembling the Framework

Steps 1-3

Retrieve the framework we last worked on in Issue 79. Position the Top Ring assembly onto the framework by aligning it over the pins on top of each Leg Support, as shown:

Steps 4-5

Secure the Top Ring assembly to the Right Leg Support with two (2) 2.5×4 mm silver screws:

Step 6

Secure the other side of the ring to the Left Leg Support with two (2) more 2.5×4 mm silver screws:

Steps 7-8

Drive one (1) 2.5×8 mm silver screw through the Top Ring and into Spacer Rod here, as shown:

Testing the Rotary Sensors

Retrieve the Battery Box and Test Board assembly and plug the wiring lead from the Left Rotary Sensor into the three-pin connector on the Test Board. Turn the Battery Box switch ON and you should see a red and greed LED lit on the Test Board:

Slip a thin opaque object such as a metal ruler between the black posts of the Left Rotary Sensor and the green LED should go out.

I just used a sandpaper stick I had nearby. The idea is that when the optical beam between the black posts of the sensor is disrupted, the signal is set to off:

Turn the Battery Box switch OFF and repeat the test with the Right Rotary Sensor.


I am happy to report that everything tested OK. Keep this framework nearby, as we will be adding the Shoulder Fittings in Issue 85.

Next Up

 Issue 84 – Upper/Lower Arms, Arm Motor/Cover/Cranks/Rods/Clutch/Pivot Mounts/Pivot Pins

One thought on “ISSUE 83”

Leave a Reply

Your email address will not be published. Required fields are marked *