Tag Archives: Stereoscopic

Stereoscopic Gimbal Wiring Details

This is an old post that I wanted to resurrect here on this blog. I will show how I connected 3 servos to a Raspberry Pi for my Stereoscopic Camera Gimbal.

In the previous demo videos of the gimbal, I was using a separate platform (PIC32) to operate the servos. To consolidate resources, and simplify design, I wanted to transfer the servo operation to one of the Raspberry Pis already on the gimbal.

A few months ago, I experimented with using the Raspberry Pi’s IO pins to run servos. The code I put together for that can be seen HERE. I’m using IO pins 4, 17, and 18 to operate the X, Y, and Z axis servos, respectively. I used protoboard to create a simple breakout board between the Raspberry Pi and the servos. External power was used for the servos. Here is the initial design sketch I put together:

In the final design, I decided to add a power LED and status LEDs for each of the servo channels. I also flipped the servo connectors as compared to the above sketch. Here is the finished board with everything connected:

servo_connect

Right now the software is converting the tracking position for each servo into an 8-bit value to transport from the Oculus Rift to the Raspberry Pi. The result of this is somewhat choppy motion in the servos, so I will be switching to use 16-bit values next time I touch the software. Besides that, it’s working well and I’m very happy with the result. The next step is to figure out how to mount this breakout board to the gimbal.

Stereoscopic Gimbal – Parts List and Detailed Photos

I’ve received a few requests for this, so I have compiled a detailed parts list for my 3D Gimbal. That list is below, followed by some detailed photos to help anyone who would like to recreate this project. I was hoping to include some build instructions, but unfortunately my constant barrage of deadlines hasn’t let up so I won’t have time. I’ve tried to double check and verify all information here but inevitably there are probably mistakes.

The estimated cost including 2 Raspberry Pis and cameras is $500 – $550.

Here are my detailed build photos along with some commentary (click for larger):

Gimbal Base

3 inch channel supporting 3/8 inch shaft and mounted to board. Notice the thrust washer (blue) between the base and horizontal channel.

3 inch channel supporting 3/8 inch shaft and mounted to board. Notice the thrust washer (blue) between the base and horizontal channel.

3D Gimbal Base Front View

Horizontal Channel

Note servo is removed

Note servo is removed

Vertical Channel

3D Gimbal Vertical Channel Front

4.5 inch belt around 1 and 2 inch hubs. I would recommend using a timing (notched) belt instead of this smooth belt because it slips too much.

4.5 inch belt around 1 and 2 inch hubs. I would recommend using a timing (notched) belt instead of this smooth belt because it slips too much.

Tilt Mechanism

The tilt mechanism (black) is all from a single kit. Servo City offers a great YouTube video on how to assemble this piece, link below.

The tilt mechanism (black) is all from a single kit. Servo City offers a great YouTube video on how to assemble this piece, link below.

Complete Without Electronics

Gimbal Full No Electronics

Complete With Electronics

3D Gimbal Electronics

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