fischertechnik 28BYJ-48 geared stepper motor

thingiverse

Enclosure for the ubiquitous geared stepper motors for the Fischertechnik construction toy system with a small footprint of 30x30x30 mm. Comes with several shaft adapters. The 28BYJ-48 is very cheap and surprisingly powerful despite its size, however this comes at the price of being very slow. Also be warned that the gear ratio given in the datasheet is not exact, it's 63.68395:1, not 64:1. You'll have to remove the blue plastic cover from the steppers before assembly with the help of a simple knife. Also, completely remove the two flanges at the sides with a metal saw or a strong pair of tin snips. The latter is preferable, as you don't want to get metal saw dust inside the plastic gear box. Use a drop of super glue and a vise to seal the enclosure permanently. Optional: I recommend modifying the unipolar 5-wire stepper to a bipolar 4-wire stepper before sealing the enclosure. Simply cut or desolder the red cable and cut the PCB's middle trace. This allows a more fitting compatible voltage of up to 10V and should double the stepper's torque. You'll need an A4988 or similar driver (e.g. my StepFish controller or the really cool ftPwrDrv Controller) instead of the ULN2003 usually used with these steppers after the conversion. Limit the current to 100mA and speed to 100 steps per second (100Hz). Thank you to David from the Fischertechnik community forum for allowing me to link to his demonstration video. His robot arm uses three 28BYJ-48 steppers for the outermost joints: https://www.youtube.com/watch?v=4Liz-WNupDA Please "like" this thing or post your make as a token of appreciation for my work. Find my other Fischertechnik designs here.