The carousel is what holds the reagents. It has slots for 12 reagents (although the center one has no stopper, so is usually left empty). It has a top and bottom part. The bottom part contains a gear ring that the carousel stepper turns. Above the gear ring is a groove that is used in mounting the carousel to the stalk. That process will be explained later. The lower part of the carousel has nubs that fit into the upper part. There are holes for 4 screws to attach the two halves together.
The bottom part has letters for each slot. However white letters on a white background can be confusing for the computer vision software. It is recommended that the letters be darkened, to improve contrast. I did this with a sharpie.
Once this is done, set the carousel parts aside.
Next we want to get the carousel mount ready. This is what will attach the carousel to the central stalk.
The second electromagnet should be snapped into place in the mount. The wiring should exit through a hole in the bottom.
The carousel mount has 4 cups. Each of those cups will hold a ball bearing. Those ball bearing will ride inside of the groove in the carousel bottom. We will deal with inserting the bearings later as part of the final assembly. For the moment, put the carousel mount aside.
We also need to put together the carouse stepper mount.
The base of the stepper gear contains a slot into which you insert a M3 nut. A M3x6mm screw is tightened against the shaft to secure the gear to the stepper motor.
Finally, the stepper is attached to the carousel motor mount using M3 screws
Just put all these parts to the side for the moment. We will put it all together as part of the final assembly.