Omnibot 'Eyes' Modification

The Omnibot back in the day was a marvel but certainly had some interesting limitations. One item that they seemed to design as an after thought was the little round eyes. They were simple light bulbs that took a note from every other Spensor gift of the era - they flashed to the sounds that it made. Cool enough but hardly cutting edge even at that time.

Fast forward to now and even cheap toys have more impressive effects. I'd like for Omnibot to be able to express emotions with its eyes like you see in Wall-E or with the very cool Cosmo or While we're upgrading the existing functionality, why don't we improve on the expressiveness of our favorite little bot by replacing those light bulbs with LCD screens!

Parts List

• 3D printed parts set - Print these parts with 2 shells and 20% infill
  https://www.tinkercad.com/things/23Qb8W1Q9Cm-omnibot-eye-display-rig
• The original screw that holds the light bulb reflector and popout mount together.
• Original black popout mount
• 2 1.28in Waveshare round LCD Screens

Tools Needed

• 3D FDM printer or access to one
• Small philips screw driver
• Precision knife or deburring tool for 3D parts cleanup
• Drill bits - 1/8in (3.18mm)
• Drill

Pre-Build Notes

1. Warning: Before we begin, you should know that this modification cannot use the original electronics. This build assumes that you will not be using the original electronics and tape drive.
2. Note: You will want to retain and reuse the original pop-out eye holder and the screw used to hold the lense and reflector to it.
3. Note: This build does not describe a specific way to control the screens but they can be interfaced by all of the usual methods such as a microcontroller like Arduino, ESP32, Teensy, etc, or full blown PC GPIO control. What you use to control your system is up to you.
4. Note: Go ahead and print your plastic parts from the kit linked above and clean up the prints before beginning. Each of the screw holes should be drilled out with the appropriate bit (M3 holes use the 1/8th in bit). Make sure that any stringing is removed and that burrs are also removed.

Step 1 - Prep Plastics

The two 3D printed parts linked above may require some cleanup of the mounting holes or the inside edge of the screen adapters. As with any print, before beginning, debur and clean up any stringing or blobs that may have been left over from the printing process.

Step 2 - Disassembly of the Omnibot and Head

First remove the 6 screws on the back of the Omnibot that hold the front half and the back half together. Next, remove the bottom screws that hold the back half of the body to the base motor tray. This will allow the back half to be removed from the bot leaving the head and base connected.

NOTE: When removing the back half of the body casing, take care not to open too far as there are wires connecting to the battery connector, charging connector, trim pot, and antenne. Please take not that the antenne lead is much shorter and at the bottom of the bot on most models.

NOTE: If you are leaving the original electronics in place, then you will need to unplug the two wires that connect the lights in the head from the main control board. You will also need to drive the eyes with some other method than the original main control board. The two wires that connect the light bulb (6V and ground) may be used as a signal line to your new eye controller but you should be mindful of the 6V power line and any electrical noise that the older motors may introduce to the ground plane.

Third you will need to slide the head and dome out of the robot. These should not be held in by screws. Once you have that, the black 'eyes' mount that consists of the front black eyes, the middle lense, and the lightbulb reflector can be removed by gently pressing down on the inward facing retaining clips on either the top or bottom.

Forth, unscrew the single middle regaining screw that holds the lens and reflector to the mount. You will not need the lens or reflector but keep the screw.

Step 3 - Assemble the new screen mount and adapter ring

The Waveshare screens linked above are not quite as big as the original lens opening so there in this kit you'll find the screen mount plate and a thin adapter plate. This adapter plate simple fills in the gap around the edge of the screen. You can color this plate any color you like. I was originally going to print mine with black plastic to blend in but having seen the white ring, I kind of like the contrast.

Each screen will need to be connected to the mounting plate with the 4 screws that came with the screen. They are oriented with the screen connector fitting into the cutout notch on the plate. Repeat with the other screen.

Step 4 - Final Assembly

Next put the original black eye mount face down on your table, place the thin screen adapter plate on the mount. Then place the screen mount assembly on that with the center block fitting snugly downward between the two eye openings and with the screens facing down and out of the front of the eye mount.

Using the original screw, secure the whole assembly with the screw in the middle of the three parts.

Before putting the final assembled device back in the eye opening in the head, you should note that the screens natural 'top' is where the connector on the back of the screen is. So, to mount these so that your images will be right side up, when snapping the eye mount back in the head, make sure that the connectors of the screens are toward the top of the head.