Sources of inspiration:
BOM: Components:
Differences:
- stepper motor instead of DC motor
- Reasons:
- easy control over rotation speed and direction from a microcontroller
- personal preference for steppers
- controller board and touch display
- Reaons:
- to adjust duration and have it auto-stop after a predefined time
- remote control via wifi based esp controller board
- allow for different drums
- Reasons:
- the original glas is not available in german IKEA stores
- new design allows for various diameters without much adjustment (only needs the ribs inside the drum)
- also allows for having one glas per grain size so you don't need to clean the glas when moving the printed part from one grain size to another
Problems:
- Mechanics
- drive rolls did not have enough grip -> slimmer rolls did the trick (same weight on smaller area -> higher pressure per area)
- TPU ring on the holding roll slipped down -> added an edge on top and bottom
- Electronics
- sketch did not work with ESP8266 (Wemos D1 mini) -> I had not used the pin for "direction" yet; it defaulted to "8"; this interferred with pin "D3" for "step" -> changing the direction pin away from 8 solved the issue (that was a tricky one; the sketch worked perfectly on my Arduino Uno; so the only - apparent - changes were the Board (Arduino Uno -> Wemos D1 mini) and the pin (9 -> D3)
- setup appeared to be very sensitive to touch; even getting near the A4988 controller board seemed to cause the stepper to stop rotating and instead vibrating very strongly
- "direction" pin on the A4988 board was open to static -> connecting that (pull-up, pull-down or connecting it to the D1 board solved the issue
- Software
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