"Bob Blick" Propeller Clock





Project LeadChristopher Gennuso
Assistant LeadFrank Graffagnino
Structural AssistantAristille Breaux
Design AssistantJeremy Moreau



This clock is no ordinary clock. It consists of seven spinning light emitting diodes (LEDs) that create an allusion of a 7 by 30 array of lights. A microcontroller that sits atop a circuit board screwed to the shaft of a motor controls the specific intervals in which the LEDs blink to create the illusion when the LEDs spin by quickly. This is done through the detection of motor speed and interval timing. It has implications not only as an illusion to the eye, but also in the field as advertising devices and alternatives to conventional displays. This clock is somewhat more difficult to construct than other similar clocks because of the fact that the entire board must spin but also be able to get power. This requires ingenious mechanical and electrical design.

The design of this clock comes from Mr. Bob Blick. Since he published the plans on his website, many people have built variations of Mr. Blick's clock. Our group would like to thank him for making this knowledge available online. The original plans can be found here.



Construction Journal

Sunday, February 11, 2001 - Day 1

First we played with the VCR head motor similar to the one Bob Blick and others used in their clock projects and realized we were getting nowhere. We then found a web page by Bob Blick (the original designer of the propeller clock) on how to use a dc motor from an old 5.25 inch floppy drive. It was very detailed and specific on how to mangle the motor so that power could be drawn from the spinning armature. We found a full height floppy drive in the back of Shelby's office (the lab assistant for Electrical Engineering). It was in an old portable PC, which we later found out to be the first portable PC known as the OSBORNE.


We took it apart and mangled the one of the floppy drives. Inside we found a Buehler motor exactly like the one on the web page.


Opening up the motor, we assorted through all the components (see Bob's page for details of this). We discarded the frequency generator assembly, and then we got a step-up bit and drilled a 0.625" hole in the motors end cap and acquired a bearing with a 0.625" outer diameter and 0.25" inner diameter. To drill the hole in the cap we needed a step-up bit, which we purchased at Home-Depot for about $32.00. We then got a 0.25" threaded spacer and used a hacksaw to cut three notches in the spacer.

Next we needed to solder the three wires to the commutator but we did not have the proper soldering iron. We also needed to attach the threaded spacer to the shaft but didn't have any JB Weld. We called it a day.

This is basically what we had when we finished day 1:





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