Mechanically Scanned Clock
Bob Blick's "Propeller" ClockThe enclosure is done! 
(Click on the image for a bigger view)
More pictures:
Here's what it
looks like w/o the strobe...
"printf" feature for debugging spinning hardware!
Artie Schleifer contributed the woodwork and the machining to modify the DC motor.
Motor modification details
Back side of clock.
Back side of propeller.
My version (3) of Bob's clock is designed to be turned on to
display the
time on demand.
To do this, I need a way of keeping time when the propeller isn't
spinning.
A 3V lithium watch battery
is used to run the real time clock on a Rabbit 2000 core
module running eForth (see Rabbit
Forth). Now running gForth. Note that the Propeller Clock uses RCM2300 serial port A to talk to the display and serial port C for control commands.
When the propeller starts, the display processor (a PIC16F873 on the
back side of the
propeller) receives the current time from the Rabbit via a RF
link.
The display processor then keeps track of the time
based on its 16.0 MHz crystal for the duration of the run.
If you are interested, you can read about some of the technical problems and their solutions in Propeller Clock Design, and design calculations for the DC-DC converter.
The clock must be balanced.
The display modes presently supported include:
Standard digital clock (12 or 24 hour format)
L-mode (1 Hz display of all digits in the same position)
Message window (12 characters in 180 degrees)
printf (displays the contents of any data address at positions 0,1)
A-mode (2 Hz serious jitter)
The display modes to be completed:
Analog hands
Pendulum
Version 3 files:
Display Processor Schematic
Wiring harness to LED Drawing
Display Processor source code (PIC16F873) pclk3_r5.asm
Control Processor Schematic
Control Processor source code (gForth for Rabbit2000) rabbit_PCLK3.fs
Python code to communicate with the Control Processor via Bluetooth to display the date clock.py and module to convert strings to display index pclk.py
Forth code for the CP LED & switch rabbit_io.txt
How to make an In-System Programming cable
Power Supply Schematic
Power supply pinouts: LM317, LM340-5, LM2941
How to skywire the power supply
More clocks: Nixie
Previous versions
Version 2
Version 1