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I figured you guys might be interested in some of my tinkering with the Launchpad.  Hopefully by putting a few of my projects up here it will also keep me accountable for finishing them.   This is o

Brilliant! I made a shameless copy of your design last night by modifying a $3 clock from KMart. It's tethered to my launchpad at the moment, but a standalone board with one of my spare 2452's will be

I've improved the code a little, so here is my updated version. Fixes include: 1. Using a bit array instead of a byte array, dramatically reduces the amount of RAM used, so that smaller MSP430's can

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@@grahamf72, That is awesome!


I think the hardest part of the project was finding a clock with a loud enough ticking noise.  Most of them are actually advertised as being quiet.  The cheaper you go on the clock, the louder it will probably be.


I had the same backwards problem crop up a few times which led to the adjustable pulse width; even at 0x4000 it still happens sometimes on startup, but that might just be an initial state issue.  I found that a short burst of manual force to the clock mechanism would restore proper drive direction.

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  • 5 months later...

The current, voltage, and switching speeds are so low that you can use practically any transistor in this project.  The only requirements are that you have two NPN and two PNP transistors.


You can even get away without the transistors, driving the coil directly from the MCU pins.  I wouldn't recommend this on the MSP430, but people have done it.  With the small, cheap mechanism I am using, the current required to drive the mechanism does not exceed the absolute maximum values.  Nonetheless, I am using an H-bridge just for safety.  For MCU's with greater drive current, there is absolutely no need for external drive circuitry, so if you have any PICs or AVRs laying around, it would be best to just use those.


One thing I have wondered is whether you could use multiple GPIO pins to distribute the load.  Using two GPIOs on each side (a total of four pins) should bring things within recommended values.  Does anyone know of the issues involved in doing this?

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Since the clockwork I am working with is a continuous type ("sweep movement"), it needs an 8 Hz waveform to move 1 s, and I'm currently trying to figure out how to actuate it properly with the irregular timing.

Also I noticed that the stator seems to be slightly magnetized (to determine the rotation), as the same timing for both polarities causes different motion.

I was looking at different "Vetinari" clock projects and found another, minimalistic approach using an MSP430G2211: http://renaud.schleck.free.fr/horloge_vetinari.php

He does not use a sequencer but randomly varies the length of the second-ticks by multiples of 1/64 s, and keeps track of the overall error.


I think this thread's project's code could also be ported to a smaller controller if one would replace the large 128 value array with an 8 int array and bit operations / pointer arithmetic.

I would also think there must be a more efficient way to randomly set 32 of 128 bits, but I'm not a computer scientist..


I'll report back once I've got the motor under control - thanks for the inspiration!

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If the motor can be reliably controlled at different speeds, probably even the regular tick motion could be created (although more silent), and thus also the irregular tick.

But currently, stopping and starting the motor will cause step-loss which of course is not an option. If this can't be overcome, i.e. the motor needs to keep running as fly-wheel, indeed only an irregular sweep is feasable, but I think this still may be interesting to notice.

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