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====== Nixie Clock ====== | ====== Nixie Clock ====== | ||
- | 工事中 | + | I designed and built this nixie tube clock in my senior year of high school. It's a basic 4 tube design controlled by a Microchip PIC microcontroller. |
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+ | {{:nixieclock-1.jpg?600&direct|}} | ||
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+ | ===== Introduction ===== | ||
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+ | In my senior year of high school, the [[http://www.nutsvolts.com/index.php?/magazine/issue/2006/10|October 2006]] issue of [[http://www.nutsvolts.com/|Nuts and Volts]] featured an article about a Nixie tube clock. The [[http://www.nutsvolts.com/index.php?/magazine/issue/2006/09|previous issue]] had discussed a high voltage power supply built around a PIC microcontroller. I had been experimenting with PIC microcontrollers for quite some time before and I was intrigued by the prospect of using a PIC microcontroller to generate a rather high voltage from a logic-level supply. I didn't have much use for it, though. After seeing the Nixie clock article, I now had the perfect application for it. So, I bought several tubes off of ebay, direct from the Ukraine, and got to work. | ||
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+ | The most important part of the clock is the nixie tube. I wanted to make a clock with a low part count and a small physical size, so I settled on a four tube clock. I did some research online to determine the most optimal drive configuration for the least complexity hardware-wise. Many designs biased the anodes directly and then used either ten transistors and a demultiplexer chip or a special high-voltage demux chip per tube. I definitely liked the hv demux chip idea because it means I need one part instead of 21 (demux + 10 transistors + 10 bias resistors). Another site that I looked at added anode-side switching and then used only one driver chip. I really liked this idea, primarily because the driver chips are expensive and, just like the tubes, I had to order them directly from the Ukraine. Replacing three driver chips with eight transistors and eight bias resistors seemed like a fair trade. | ||
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+ | Then I had to figure out how to do the other thing the clock will have to do well -- keep track of time. I settled on a Maxim/Dallas part, the [[http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3914|DS1340C]], with an I²C interface and a built-in crystal, further reducing the parts count. | ||
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+ | In researching how I would build my clock, I looked at many pictures online of other clocks. Some were completely over-the-top, some were too simple. I wanted a sleek, modern looking clock that isn't too difficult to build. One of the ideas I liked about one of the completely over-the-top clocks is blue lights underneath the tubes. The little hole in the bottom of the spacer on the bottom of the tubes that I bought happens to be just the right size for a 3mm LED. So I bought a bunch of 3mm blue LEDs off of ebay. | ||
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+ | For the case, I decided on a simple design based on acrylic. The top and bottom would be black acrylic and the sides would be made of clear acrylic. | ||
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+ | I decided to write the firmware for the clock in C in [[http://www.mikroe.com/|mikroElektronika]]'s [[http://www.mikroe.com/en/compilers/mikroc/pro/pic/|mikroC]] development environment; I had bought it along with an EasyPIC4 development board from them some time before. | ||
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+ | The result of a pile of work spread out over several months is shown above. | ||
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