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TIA wiki user D18c7db contributed this wonderful guide for the Fantazein moving wand clock. He describes its function and even created a circuit diagram for it!
Check it out after the jump.
This is a Fantazein moving wand clock, the type that creates the illusion that text floats in midair as seen in the small picture below.
This guide is not so much on how to take the clock apart which is trivial. Just remove the two screws in the metal baseplate and the two halves of the plastic case come apart. This is more of a guide of what’s inside.
With that in mind, the picture below shows the front of the circuit board assembly with the battery holder and the programming keypad. The wand with 8 red LED can be seen protruding from the top. This wand moves at about 12 oscillations per second becoming almost invisible to the eye while the LEDs flash creating a floating text effect.
Below is the back of the circuit board. The large chip is an Atmel AT87F52 microcontroller that is the brains of the whole clock. In the middle are two flat iron bars spaced apart with coils wound onto them. The two coils are wound in series and are pulsed on and off by the microcontroller. A permanent magnet affixed to the wand creates a repulsive force when the coil is activated pushing the wand slightly to one side.
Since the coil can only be turned on or off and the polarity is not reversed, the repulsive force on the wand is always in the same direction. The wand is held in place through a springy thin steel blade which is firmly affixed to the L shaped aluminium mound bolted to the circuit board. The springy steel blade has a strong tendency to return the wand to the vertical position. By pulsing the coil on and off an oscillation is induced in the wand which initially only moves back and forth a little but as the coil is pulsed the oscillation becomes wider.
Think of is a a swing. As you lean back you swing only a little but as you keep leaning back and forth at the right time you increase your swing arc significantly.
The side view below of the circuit board shows the coil assembly as well as the wand with the permanent magnet. An aluminium bar is mounted to the wand which passes between an LED and a photodetector as the wand swings. This is used by the microcontroller as a feedback mechanism to detect the wand swing and time the coil pulse timing and duration accordingly.
Closeup view of the semiconductors below. The large chip is the microcontroller, to the left of it as a LM339 quad op-amp. Above the micro is a LS244 driver and to the right of that a small 93C56 EEPROM.
Finally below is a hand drawn reverse engineered circuit diagram of the whole clock. The schematic is elegant in it’s simplicity. The micro is read protected and the firmware could not be read however since it’s socketed, a new micro could be fitted and given enough skill one could develop a replacement firmware code. I started doing that and got as far a creating a sustained wand movement that would recover if the wand was stopped by an obstacle such as your hand but other more pressing matters put this project on the backburner.
Thanks, I always wondered what the moving part looked like on the inside.
is good
Your schematic is not to clear. I have one of these clocks and it has quit working. I would like to have a clear schematic so I can troubleshoot and find the problem. I worked in electronics for years and now have retired.
Thanks
Hi D18c7db:
Great work - and indeed a very fascinating device. But after a few months - the triangular metal flange broke and Fantazein - the manufacturers were not of much help. I am unable to find a substitute for the same. I tried to make 1 myself using metal strips - did not work. I know from your page you are a very busy person - am trying my luck here - it the only thing am left with - as far as this clock goes.
Thanks for any help.
Ravi Upadhyaya
I need the wand for my clock could you please send me info on how i can replace it.
how can an inventor think of this stuff??????
Hi,
Thanks for the useful schematics. I may try replacing a few parts in a broken fantazein clock I have. The wand has stopped “pulsing” and 8 leds are on solid with minimal and sometimes no movement. Sometimes, the wand pulses twice with a bigger movement, and sometimes it works for a day, then goes back to no or minimal pulse/solid leds.
I may replace the LM339, KSP2907A, or the 470mf 25v electrolytic. I have checked the voltages from the power supply(healthy 12vac), and off of the 7805 (5 vdc). I just hope the problem is not in the big or small 8pin proms.
The unit broke within less than a year from purchase(2000-2001), and when I contacted the fantazein customer support, they wanted me to break off the top of the wand(leds) and send it to them with a payment of $50 for a new clock. I was not willing to do this which may only be a part that might cost less than a dollar to fix.
PS - one more thing, my 8pin prom is under a different part number, 93c66 instead of 93c56.
My clock stopped working after 4 years, is there a place that repairs them ?? Winter9877@aol.com
This is exactly what I want from past few months. I say a sample image on site and till now I was thinking that the wand was moved forth and back by reversing the coil current flow or something else. And I have a doubt about how they are able to stop and pull back the wand in reverse direction with such a fast movement. And I thought of constructing one like this. I have tried with Hard disk head. I got sufficient oscillations/second. But I am unable to stop the wand at a particular position. And it has very less deviation. So, I thought of making the coil by myself to get more deviation. But as I am not an expert with mechanical or electro-magnets I could not succeed. If anybody can post few more pictures/details about the coil and wand move mechanism I will get an idea from that to construct my self. Once I built complete set i will post entire project.
My clock has worked very well for 6 or so years. I unplugged it 4 days age and just now plugged it in but it justs sets there motionless. Directions unknown. Isn’t there a trick to restarting it? Transformer is warm, and LEDs blink when plugging in and out. Can you help me?
Thanks