This project thread was split from mrclean's inquiry
here about using a small motor to generate linear motion.
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Without revealing the theme, the mechanics that Josh and I have been discussing have evolved into something more complicated (and cooler
) than previously discussed in this thread.
- An arm raises/lowers about 2-3(?) inches.
-- There is a 608 bearing (or similar) on the side of the arm.
-- The item being raised/lowered at the end of the arm weighs less than one ounce.
- A motor moves a platform 8-10(?) inches horizontally.
-- The arm is mounted on this platform. The arm's fulcrum axis is perpendicular to the direction of travel.
-- This platform is WAY too heavy for the 28BYJ-48.
- The rise/fall of the arm is controlled by the bearing rolling through a track on a vertical piece of MDF (or layered acrylic?) mounted parallel to the moving platform.
-- If the arm is moving left to right and the track is shaped like this
----\__/\_/\___ the arm will start high, then dip low, pop up/down twice and end low
-- The bearing might pop out of the track if improperly aligned. Proper design should minimize this risk.
- It's probably best to use a leadscrew, pillow bearings, and two limit switches (not shown) in the horizontal drive mech.
-- It's far more durable than a scotch yoke .
-- Used in the Z-axis of many 3d printers and CNC machines.
- Will need to find/write Arduino code to make the motor run one direction until it hits a limit switch, then run the other direction until it hits the other limit switch.
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NEMA series motors with A4988 driver boards have the power to do everything Josh wants to do, but they are much louder than the 28BYJ-48.
The hard part is finding something between the $2 28BYJ-48 (380 g-cm) and a $10-15 NEMA 17 (60oz.in ==> 4320 g-cm?) commonly used in 3d printers/CNC machines.
Any suggestions for an inexpensive, quiet stepper motor/driver combo mid-way between the 28BYJ-48 and NEMA 17?
Scott