Introduction: Servo SG90 With Unmodified Lego


Using cheap servo in Lego-arduino builds.

Newer version, with less parts:

There are several guide how use SG90 servo with lego. Most of them require customization of lego/servo or 3d printed case.
This example is using original LEGO pieces. I tried to use parts that easy and cheap to get. Some variations are possible if you don't have exact parts.

Part list (with lego ids):

SG90 servo 2 screws

2 screws

Brick, Arch 1 x 4 (3659) x2

Plate 1 x 4 (3710)

Plate 1 x 6 (3666) x7

Technic, Axle 3 (4519)

Technic, Axle 4 (3705)

Technic, Axle Connector 2L (6538)

Technic, Brick 1 x 4 with Holes (3701) x 5

Technic, Brick 1 x 6 with Holes (3894) x 15

Technic, Bush 1/2 Toothed (4265a/4265b) x2

Technic, Bush 1/2 Smooth (4265c)

Technic, Bush (3713)

Technic, Gear 12 Tooth Bevel (6589)

Technic, Gear 16 Tooth (Old Style with Round Holes) (4019)

Technic, Pin (2780/4459/3673) x 12

Step 1: Servo

Use 2 screws to attach gear to white part that come with servo. Cut corners with e.g. knife.

Step 2: Middle Section

Step 3: Attach Servo.

Put servo under black arches. Fix it with 1x6 brick (red).

Prepare other axle with gear.

Step 4: Attach Gears.

Step 5: Fix Servo Axle.

Fix servo axle with 2 bricks and plate. This will prevent axle from leaning to sides, or detaching from servo.

Step 6: ​More Durability.

This will add extra durability.

Step 7: Variations.

Examples if you want to put servo on side.

Or if you want to attach something to servo closer to the axle.

Step 8: In First Robot Build.

Video show how it could be used to make simple robot with arduino.

It could answer yes/no to your questions (controlled by 2 buttons).