[Concept instructions/Blueprint] Stargate - Rotate glyphs with stepper motor

thingiverse

This _thing_ is a concept/blueprint for '5ft Lighted Stargate' (Thingiverse ID 2783393) to modify it, so that the glyph ring can be driven by a stepper motor. Please note, that I did this _work_ for my version of the '5ft Lighted Stargate' which has only the size of 66% from the original _thing_. I can only *describe* what I did or what my experiences are and *provide respective models and a concept SketchUp project* (the \*.skp file), so that you are able to adapt/improve it for your Stargate. In the *Thing files* sections are two videos which are showing that it *works* for my Stargate. When I remember correctly in one of the comments from '5ft Lighted Stargate' (Thingiverse ID 2783393) was the idea to use a rubber wheel and this was my starting point. It is logical to use one of the bearing housing as a drive wheel housing. Therefore I adapted the _Bottom\_Center.stl_, so that a drive wheel of 15mm in diameter and its shaft can be put into it (see Concept_Bottom_Center.stl). I also kept a cable tunnel for optional LEDs. The Stargate was only assembled to the half at this point (Bottom elements, bearings, glyph ring). The Inner and other parts were not assembled. Before I changed other parts I wanted to find a suitable *wheel*. I bought some Lego rubber wheels with and without tread pattern, because I did not knew which had more friction based on the contact pressure. I created a rim with a shaft, fit the tire on it and made some tests. In my case (this can differ based on print material or used tires) the result was, that I had a wheelspin with each Lego tire. I searched for a different material, which had other friction characteristics with the print material. After I rubbed different household items on the PLA I found a good condidate which was a rubber band. I bought some rubber tube (often used for slingshots - I used 14mm in diameter), cut a 5mm piece from it and assembled it onto the rim with the shaft. The test was successful. I designed a printable rim for a 5mm shaft -> see Concept_RubberRim.stl The rim needs a 3mm setscrew and a 9x3mm bearing with a 5mm hole for the shaft. The bearing is the dark part in the pictures. I modified the Inner part (my remix with the Thingiverse ID 4348247) at the bottom so that it has a fix point for the bearing and some space so that the rim can rotate freely. The first time the rim with the rubber were not properly pressing onto the glyph ring and therefore the shaft fix point was moved a bit more to the ring. Then I created a plate on which the stepper motor is mounted on as well a second bearing to secure the shaft. The hole for the bearing has to be *tight*, so that some force has to be used to press it into. This should hopefully prevent that the bearing looses over time. The plate is glued onto the back of the Concept_Bottom_Center.stl. Pay attention that no glue dripps onto the backside of the glyph ring (by running down the parts when the glue is to watery), which can prevent it from spinning when hardened. I bought a set of 90 degree gearwheels (1:1 translation in my case) and mounted them onto the dive shaft as well on the stepper shaft. *Stepper motor* To drive the stepper motor I use a *DRV8825 stepper motor driver carrier* from 'pololu'. The following website has a well explained guide for this driver and how to setup and program everything with an Arduino Uno https://www.makerguides.com/drv8825-stepper-motor-driver-arduino-tutorial/ . I hope this helps you by modifing your Stargate to make it more *Stargate like*. Last note: I am working on a Ardunio and PC program to dial Stargate addresses and that the glyph ring rotates accordingly. Because I planned this from the beginning I inserted NFC tags and magnets into the glyphs, to be able to read and locate a glyph. When this also works I try to share the concept and program code as soon as possible.