I am looking to build a Kinetic Sculpture where 500 (or so) motors which raise and lower weights(such as Christmas tree decorations), using thread and reels to visually mimic waves, 3D patterns etc. See an example at https://www.youtube.com/watch?v=NXuQnDeIyY8
There are some technical questions:
1. Motor type
Motors are low-power (20gm weights) but 500 located in reasonably close proximity. Motor selection needs to consider: cost, reliability (24x7 operation), low power (i.e. avoid fire hazard), reliable positioning in response to command (+/-5% including start-up initialisation). Currently a stepper motor (say NEMA 8) seems preferred. By comparison DC motors with encoders have low heat and low(ish) cost, but not sure about reliability and they require a closed loop PID operation, needing more inputs and more complicated. Thoughts?
2. Start-up positioning
An IR Obstacle Avoidance Sensor seems cost effective and practical. I.e. detects when the weight nears the top. But is there a easier method to reel the weight out at initialisations and detect when the load on the motor changes from DOWN to UP (i.e. -torque to +torque). Is it more practical to implement?
Thanks in advance.
There are some technical questions:
1. Motor type
Motors are low-power (20gm weights) but 500 located in reasonably close proximity. Motor selection needs to consider: cost, reliability (24x7 operation), low power (i.e. avoid fire hazard), reliable positioning in response to command (+/-5% including start-up initialisation). Currently a stepper motor (say NEMA 8) seems preferred. By comparison DC motors with encoders have low heat and low(ish) cost, but not sure about reliability and they require a closed loop PID operation, needing more inputs and more complicated. Thoughts?
2. Start-up positioning
An IR Obstacle Avoidance Sensor seems cost effective and practical. I.e. detects when the weight nears the top. But is there a easier method to reel the weight out at initialisations and detect when the load on the motor changes from DOWN to UP (i.e. -torque to +torque). Is it more practical to implement?
Thanks in advance.