LED Hard Drive Clock 3.5"

[noise0]

LED Hard Drive Clock 3.5"

excuse me sir
i come with a neat question:

do picaxe have enough computation speed in order implement a system like this one?

http://www.ian.org/HD-Clock/


i have calculate that if ad HD do 5000 revs per minute this means that one sngle revolution occur in 12 ms
in this period of time the microcontroller have to issue at least one hunderd of instruciont in order to obtain a decent resolution..

so can picaxe fit for this task?

thanx and excuse me for poor english
________
Vermont marijuana dispensary

 

[westaust55]

This sort of POV (Persistence of Vision) type project does arise on this forum form time to time. You could search the forum for past threads.

A PICAXE chip operating at 4MHz takes roughly 250 microseconds per instruction - thats a rough average and there have been some past thread on instruction speed if you do a search.

So in 12 milli-seconds you could achieve around 48 PICAXE BASIC commands.

So then you can increase the PICAXE speed through 8MHz, 16MHz, 32 MHz and even 64 MHz on some of the latest chips.

Doubling the speed may not double the number of BASIC commands but you will certianly see an improviement with each step up in PICAXE clock speed for most programs. Note that a few commands do drop back to the default speed for that command and others may not work at other than the default speed. (Read the manuals to determine those involved here).


I have not looked into how much program code you need but with a high clock speed something make be possible but very unlikely at default slow speeds.

As a thought:
What if you only displayed the illunimated sections once every three revolutions. Hours on one pass, minutes on a second and seconds an a thrid pass. Still all done in 36 milli-seconds.

Visible "Flicker" starts to come in with refresh rates of less than around 20 - 25 times a second. At 25 times a second that equates to 40 mili-seconds so using three revolutions is a possibility.



.

 

[techElder]

Just a thought ...

Why not slow down the hard drive speed? Give yourself more time for more instructions.

 

[westaust55]

Changing the HDD disk speed would involve constructing a new controller.
Not impossible but would add to the PICAXE program load, so could be going full circle

 

[Dippy]

"full circle" - haha, nice one.

 

[hippy]

With 5400rpm = 11ms per revolution it certainly looks possible -

Do
Calculate pauses
Wait for synch
Pause to seconds position
PulsOut seconds LED's
Pause to minutes position
PulsOut minute LED's
Pause to hour position
PulsOut hour LED's
Loop

That works fine when the clock hands are not over each other and when they are ( or over the synch point itself ) you can extend the pause to add another resolution, or simply do it as three 'wait for synch' then pause per hand as Westaust55 suggests.

When all hands are over the synch point it will take six revolutions to refresh the entire image but that's probably acceptable.

 

[cactusface]

Hi,
This looks interesting... But why not use a couple of CD's? and a good DC motor, not sure you'll get 5400 RPM. I think it could work, might give it a try! Must take a better look at the link, etc.... The Leds I take it are RGB's.
Anyway it was JUST a thought.
Regards
Mel.