![]() Luckily the voltages on the pcb are connected in a way that makes it possible to place a voltage regulator on it and get the 5V out of the 12V. The floppy disc drives I used need two different voltages to work. The motors should be found rather easy in surplus stores for a small amount of money. The speed of the motors is rather constant because it is regulated. These motors are brushless dc motors that are very silent while running. I decided to solve most of the problems by using motors of old 5 1/4 inches floppy disc drives. Here are many links to different solutions and pictures of clocks that use brushes to transfer the power to the pcb. Phillip used a fan as a motor and build his own generator. One can also mount a battery onto the moving part, but this battery need to be replaced now and then. Brushes make noise, give bad contact and are ugly. Other people transferred the power using brushes. These are hard to find nowadays and the speed is not very stable. The motor that bob used was a non regulated one from a very old floppy disc drive. He modified the motor to use an extra coil as a generator for powering of the circuit. Bob used a motor from an old floppy disk drive in his project. The motor has to be silent, it has to make more than 25 turns per second and the power for the clock circuit has to be transfered somehow to the pov pcb that is mounted on the turning spindle of the motor. One problem building such a clock is to find a motor. All new clock builds should use the CNC Shield V4 design.Meanwhile the Propeller Clock of Bob Blick is known quiet well in the DIY communities. They will probably be on sale at a reduced price on Etsy until they are gone. I still have a lot of custom circuit boards for this driver design. An alternate method of building the circuit using only resistors is shown to avoid the high international shipping and customs charges added by Etsy. A kit is available for the custom motor driver. ![]() The old-style stepper motor driver circuit drives a 30-35 ohm NEMA17 stepper motor directly through binary weighted resistors. This gives the clock an accuracy of a minute or two per year as the Arduino matches the stepper motor speed with the real time clock. A DS3231 precision real time clock was added to one of the unused stepper motor sockets. ![]() The default A4988 stepper motor driver was replaced with a much better Trinamic TMC2208 driver to make it run quietly. The CNC Shield V4 board was originally designed for a CNC engraving machine with three stepper motors. Download the Assembly Notes plus the CNC Shield V4 Addendum for the complete set of instructions. The new driver has the following improvements:īoth stepper motor driver circuits are supported, although the CNC Shield V4 method should be used for new builds. An even quieter stepper motor solution was added in January 2023 that uses a CNC Shield V4 with a TMC2208 and a DS3231 precision real time clock. This was the quietest method I could find at the time. The original design used a custom circuit board to drive the stepper motor. ![]() Accuracy can be tuned to better than one second per day. All the gears are exposed, and the sweep second hand provides a great look. This is a nearly silent motorized desk clock using an Arduino Nano and a custom drive circuit to control a stepper motor.
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