[Engineer2you] built a nixie tube clock and claims it is the simplest design. We felt like that was a challenge. In this design, the tubes are set up as a matrix with optoisolators on each row and column. With 60 segments, the matrix allows you to control it all with 16 bits. There are six columns, each corresponding to a digit. That means each row has 10 lines.
ah, i assumed we were talking simplest hardware design, i.e. minimal components. Anyway, wifi is ubiquitous and there are more than 4000 public NTP servers available (check out the NTP Pool project). NTP also provides for a very accurate clock, since it always keeps it in sync within a couple of milliseconds.
Nixie Clock Claims To Be Simplest Design
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.
As they say, the simplest design usually turns out to be the best and most elegant solution to the problem. The winning Geyser Tube design was a clear plastic tube with a special fitting that twisted onto any soda bottle. The trigger pin at the bottom of the tube prevented the Mentos from falling into the bottle until you pulled the string attached to the pin. The moment the pin was pulled, a slider ring resting above the pin fell into place and covered the holes where the trigger pin once was. The Mentos mints then dropped into the soda. But there was one added bonus: the restricted hole at the top of the plastic tube helped to build up more pressure in the bottle and launched the soda up to 30 feet into the air!
Heat exchangers are typically classified according to flowarrangement and type of construction. The simplest heat exchanger isone for which the hot and cold fluids move in the same or oppositedirections in a concentric tube (or double-pipe) construction. Inthe parallel-flow arrangement ofFigure 18.8(a), the hot and cold fluidsenter at the same end, flow in the same direction, and leave at thesame end. In the counterflow arrangement ofFigure 18.8(b), the fluids enter atopposite ends, flow in opposite directions, and leave at oppositeends.Figure 18.8:Concentric tubes heat exchangers[Parallel flow][Counterflow] Figure 18.9:Cross-flow heatexchangers.[Finned with bothfluids unmixed.] [Unfinnedwith one fluid mixed and the other unmixed] Alternatively, the fluids may be in cross flow (perpendicular toeach other), as shown by the finned and unfinned tubular heatexchangers of Figure 18.9. The twoconfigurations differ according to whether the fluid moving over thetubes is unmixed or mixed. InFigure 18.9(a), the fluid is said to beunmixed because the fins prevent motion in a direction () that istransverse to the main flow direction (). In this case the fluidtemperature varies with and . In contrast, for the unfinnedtube bundle of Figure 18.9(b), fluidmotion, hence mixing, in the transverse direction is possible, andtemperature variations are primarily in the main flow direction.Since the tube flow is unmixed, both fluids are unmixed in thefinned exchanger, while one fluid is mixed and the other unmixed inthe unfinned exchanger.To develop the methodology for heat exchanger analysis and design,we look at the problem of heat transfer from a fluid inside a tubeto another fluid outside.Figure 18.10:Geometry for heattransfer between two fluidsWe examined this problem before inSection 17.2 and found that the heattransfer rate per unit length is given by
i really love your design clean and simple. I have looked at the schematic, the power supply is a bit different than other supplies used in nixie clocks can you give me some more details about it ? :)
The double pipe heat exchanger, as seen above, is perhaps the simplest heat exchanger in industry. As a result, there are many, many options to choose from to buy, or they can be made custom to fit the specific needs of the project. They are most useful for small-capacity applications where the total heat transfer surface area is
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