"Propeller Clock" Mechanically Scanned LED Clock
Seven light emitting diodes spin, giving the illusion of numbers in the air.
This is the first clock I ever built. I've built a few LED signs, but they get boring because I already know the message.
How this clock works:
A motor spins the "propeller", and a small microprocessor keeps track of time and changes the
pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. It is an illusion, but it works nicely.
If you want to build this clock, you will need a few things, including:
Skill with motors and mechanical things.
Prior electronic experience.
A dead VCR or floppy drive or other source of a suitable motor and miscellaneous parts.
A programmer that will program a PIC16C84 or 16F84 microprocessor.
I have provided (almost)everything else:
The Next Page with drawings and plans.
mclock.txt A full description how to build it.
mclkpart.txt The parts list.
mclock8.asm The source code in Microchip MPASM format.
mclock8.hex The hex code ready to load into a PIC16C84 or 16F84 chip.
mclksch2.gif A large and very readable schematic diagram.
mclkmoto.gif A drawing of the modifications to the motor.
If you can't get that kind of motor, you can use the motor from an old disk drive. This page has a lot
of pictures and will take some time to load. If you use a disk drive motor or any other DC motor with brushes 180 degrees apart, you'll need the slightly revised code:
mclockt3.asm The source code.
mclockt3.hex The hex code ready to put in a chip.
If you don't have any way to put the program into a PIC 16C84 or 16F84 chip, you can build your own programmer.
Printed Circuit Board Layout for a version of the clock.
The hardware design and software are covered under the GNU General Public License.
Frequently Asked Questions: