The pendulum hasnt been built yet but I am imagining something like 1.5 fee= t long made of 1/16 inch aluminum plate. To get a better idea of the moveme= nt the pendulum with the LED will be the bottom pendulum on a double pendul= um. Here is an example of a simulation (not mine) https://m.youtube.com/wat= ch?v=3DQXf95_EKS6E Jim On July 28, 2017 1:47:16 AM EDT, RussellMc wrote: >Look at how the mechanism in typical hand-cranked torches work. >They have a sprung "detent" engaging a sharktooth shaped track on a >wheel. >A pendulum could drive a wheel in similar manner. > >What is the energy source, pendulum mass and length and initial swing? > > > Russell > > > >On 28 July 2017 at 09:16, Jim Ruxton wrote: > >> I have a small project in that I want to use a small dc or stepper >> motor as a generator to power an LED at approx. 3 volts .030 mA. I >would >> like some storage capacity so when the motor isn't spinning or slows >> down I still have some output on the LED for a short period of time >ie. >> 5 to 10 seconds or so. There will be a pendulum type arm on the motor >> shaft that when pushed will spin the motor. The LED should light no >> matter which direction the shaft is spinning. I am thinking of a >simple >> circuit using a Schottky bridge rectifier followed by a large , >possibly >> super capacitor and a DC/DC converter with an output close to the LED >> forward voltage. Maybe I should have a Zener on the input too to be >sure >> I don't go overvoltage of the cap or DC/DC converter. I was wondering >if >> anyone has any suggestions for small motors. I want it to rotate >quite >> freely so no geared motors. I assume I need a motor with a high >voltage >> winding , probably over 12 volts to get the output voltage I will >need. >> I wonder if I would better efficiency with a rare earth motor. Also >not >> sure if a stepper motor would be more efficient . I'm not sure how to >go >> about calculating the potential output voltage and current of a motor >> when used as a generator? Just thought I would send this out there to >> see if anyone has done a project like this and has any advice before >I >> go too far down a rabbit hole. >> >> Thanks, >> >> Jim >> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> >--=20 >http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist --=20 Sent from my Android device with K-9 Mail. Please excuse my brevity. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .