Lesson Plan
Materials
Need materials? Purchase the Barnabas Robot Arm at our e-store.
Classroom sets available. Contact us at info@barnabasrobotics.com to inquire.
Lesson Overview
In this lesson we will assemble the main robot arm.
Instructions
STEP 1. Attach Main Arm
Attach the main arm using:
- 2 x M3x12 Screws
- 2 x M3 Nuts (Regular)
- 1 x Acrylic Piece
.jpg)
Position the acrylic piece between the two sides of the main arm as shown. Insert the two M3x12 screws through the side plates and secure them with the M3 nuts. Do not overtighten.
Make sure the acrylic piece is seated straight and the two sides of the arm remain parallel before tightening the screws.
STEP 2. Attach Secondary Arm
Attach the secondary arm using:
- 3 x Standard Links
- 1 x Standard Link (with hole)
- 1 x Arm Joiner
- 1 x Long Link
- 1 x Cross Piece
- 3 x Circular Washers
- 5 x M3x6 Screws
- 2 x M3x10 Screws
IMPORTANT — FOLLOW STEPS 1–12 IN ORDER
Build the linkage in the exact sequence shown below. Pay close attention to which side of the arm each piece is attached to and the orientation of each acrylic piece.
Do not overtighten any screw that forms a moving joint. The connected pieces should pivot freely by hand. If a joint is too tight, the servo motor may not be able to move the arm properly.
2A. Build the first linkage
Step 1: Position the first Standard Link on the arm exactly as shown. Note the Circular Washer in between. Check the orientation before installing the M3x10 screw.
Step 2: Attach the end hole (see photo) of the Long Link at the upper pivot point using an M3x6 Screw. Leave the pivot just loose enough for the pieces to rotate freely.
Also attach the center hole of the Long Link using a M3x10 screw. Note the Circular Washer in between.
| STEP 1 | STEP 2 |
|---|---|
.jpg) |
.jpg) |
Step 3: Check to make sure that the robot looks exactly like the photo in STEP 3.
Step 4: Attach another Standard Link to the other side of the rotating base using a M3x6 Screw.
| STEP 3 | STEP 4 |
|---|---|
.jpg) |
.jpg) |
2B. Add the opposite linkage
Step 5: Attach the Arm Joiner to this new link using a M3x10 Screw. Note the orientation of the Arm Joiner and also the Circular Washer.
Step 6: Position the Arm Joiner so that the bottom hole lines up with the hole on the Main Arm as shown in the photo.
| STEP 5 | STEP 6 |
|---|---|
.jpg) |
.jpg) |
Step 7 and 8: Place the Standard Link (with hole) in between the Arm Joiner and Main Arm as shown in the photo and fasten with an M3x10 screw. Note that there is a hole in this link that lines up with the hole on the Long Link on the other side.
| STEP 7 | STEP 8 |
|---|---|
.jpg) |
.jpg) |
2C. Add Final Links For Claw Support
Step 9: Position the links so that your arm looks exactly like the photo. Make sure the Long Link and Standard Link (with hole) are aligned before continuing.
Step 10: Fasten the last Standard Link using a M3x6 screw. Check that the position of the link matches the photo.
| STEP 9 | STEP 10 |
|---|---|
.jpg) |
.jpg) |
Steps 11 and 12: Slide the tabs on the Cross Piece into the rectangular slots on the two long arms as shown. Make sure both ends are fully seated and the two arms remain parallel.
| STEP 11 | STEP 12 |
|---|---|
.jpg) |
.jpg) |
FINAL CHECK: Compare your completed assembly with the final photo. Gently move the arm through its range of motion. All pivot joints should move freely without the acrylic pieces bending, rubbing, or binding. Do not continue if a joint is difficult to move by hand. Check the orientation of the pieces and slightly loosen any pivot screw that is preventing free movement.
