Build the 1950's version of Robby the Robot's Heart Box.

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The files are on thing-i-verse. you can print the main frame as one piece if you have a large printer like the CR10S5 or in 2 parts on a more standard printer like the Prusa MK3S.

https://www.thingiverse.com/thing:4567566

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Lets start with the parts for the lower Flappers or Lifters or what ever you might like to call them. The pictures will show how the parts fit together. The assembled parts get glued in to the frame. But wait I should have shown the Flappers being installed first. So hold off on this step think of it as step 3.

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So the flappers can be held in place with a wire pin shaft about 1.5 mm. It can be 1 long shaft or 4 short ones like if you made them from jumbo paper clips. The Flappers need a return spring action. So I cut some springs from a old wind up toy spring, but any thin metal like aluminum flashing or brass from the hobby store could be cut to 6mm wide by 36 mm long. Slide the spring into the slot in the flappers and then into the slot in the frame. Then slide in the pin shaft. You can back bend the flapper to set the spring action. It is easier in the end if you do all your sanding filling and painting before doing any assembly.

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There are 2 trim rings that can be painted chrome and glued on to the from of the frame. The geneva ring has a short mount lip and the Star drive ring has a long mount lip so get them in the right paces. The Star ring is to the Left and Geneva to the right when looking from the front.

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Now lets assemble the main drive unit. Mount he gear motor with 2 screws, I use short 6-32 screws. Next glue in the Star Drive cup. You can pre paint the inside chrome now or later.

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Four skate board "fidget spinner" bearings will be used.  This the Bearing type 608. 22mmdie by 7mm thick with a 8mm hole . If you only have skate board bearings then be sure to soak then in thinner to clean out the grease so they turn easily. Slide one bearing in to the Star drive cup and 2 into the Geneva side. There are bearing caps that you can glue in place to the hold the bearings. there is also a Star drive gear that gets 1 bearing and it is held in place with a cap that has a linkage drive pin, just glue this on top the gear / bearing unit.

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Now we need some electrical contacts for the geneva lights function. A center common ground and 2 switching contacts. I cut mine from thin tined metal from the hobby store, you can use any thin metal that you can solder to and cut . I found that I could use a flat washer for the center common ground contact, I used a chrush washer from the drain plug of my Subaru that I had not thrown away. To make the two other contacts lay a piece of paper over the area and mark the shape needed and a extra bit for a tab that will push threw a slot to the back side . Use the template to cut out the metal contacts. Work them until the fit and then glue them down and solder wires to the tabs on the back side.

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With the geneva shaft pushed in to the bearings you can now glue the geneva cog into  place. The geneva drive cam can be screwed on to the motor shaft with a short #2 screw. You should be able to test run this set up now . The run direction should be clock wise when viewing from the front. You can make note of the motor voltage polarity at this time.

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Place the Star drive gear /bearing unit in place and use a screw and washer to hold the bearing on the frame shaft.

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The start unit in this build is different from the real robby in that most of you would not be able to find the correct vintage lamp for the center and that the Start would be machined from clear plexi glass then flame polished . So for FDM printers I went with a 1 part design that you can print in white PLA and just paint the star gold or silver. A LED with a 220 ohm current limit res and wires are placed inside the star unit, then glue the star drive shaft to the back. Do not glue the LED or wire. This way as the star turns back and forth the wire and LED can stay stationary and the wires will not break over time.

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Slide the star drive crank over the wires for the star LED and glue it to the shaft. You can now place the linkage in place and hold it there with 2 screws and washers. I put a bit of grease on the linkage shafts first .

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The geneva is designed to use 4 Jumbo "10mm" LEDs . glue them in place with there negative leads facing the outside edge.

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Now solder all the negative LED leads together. I used some spring loaded carbon brushes made for model trains, they come in 14mm and 16mm long versions, I am using 3 of the 14mm brushes for this project. Solder a wire to the brush end of one and slide it in the hole closest to the center of the geneva then to the negative LED wire.

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Solder the positive leads of the opposite LEDs together. The solder some wire to the ends of the bushes and slip them in the two mouting holes. You do not need to glue the brushes in place they can not move once the geneva dial is in place. If you solder the wrong group of LEDs to the wrong brush then you LEDs will stay lit vertically instead of horizontally as intended.