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How To assemble and connect the optocoupler.
With a multimeter it's easy to figure out if two of the wires are of the same phase, it's when you can mesure a resistance value between them (at the condition that it is a 4 wires stepper motor. As long as you have the 2 phases connected it's not a big issue if the rotation is inverted as you can change its direction in the file hardwarecfg.json with the obvious setting “invert”, one for each of the 3 motors.
Using elastics
Common household elastics are at the very hearth of the Gugusse, to create the tension on the film the two swinging arm are pulled one to another with these. The film tension is directly related to the strength of the elastics themselves, it doesn't need to be much but not enough and the film will have issues advancing while too much and the film will be submitted to too much abrasive friction at the gate, when it won't simply break. Just place elastics to right under the rollers. An elastic varies its tension according to the distance that it is stretched, the distance they will be kept apart at all time is the distance between the 2 arms when they are each at their middle position.
