Z80 Monsputer: CPU board cleanup

I posted some pictures of the Monsputer CPU board, which had numerous ugly patches. By subsituting a smaller chip with more pins, I was able to put all the glue logic in the CPLD. Here is the top and bottom pictures. Much cleaner … well, for a manually routed PCB. Also, a Dalas DS1312 makes a better circuit for powering the CMOS 8K RAM.


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Earth’s orbit

Here is a common concept among flat earthers: the Earth circles the Sun. In order to keep up and pass it (circle it) Earth must speed up to pass, and then slow down once it’s passed (circled).

It’s partly true. That’s the acceleration component along one axis.

There is also another component of this acceleration along a perpendicular axis: once it’s passed the sun (in one side) it accelerates and slows down to get to the other side.

These 2 components combine into a circle, or a vector that’s oriented towards the center of the orbit. You can see clearly the principle here:



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Antarctica cup proves the globe earth


“The Racetrack outer and inner boundaries are located on latitude 45° South and latitude 60° South making the Racetrack 900 nautical miles wide. The Southern Ocean officially starts below latitude 60° South (International Hydrographic Organisation (IHO) www.iho.shom.fr/ . Latitude 60° South is also the border of the Antarctic Treaty Organisation www.antarctica.ac.uk/aboutantarctica/treaty

Here are my calculations: in the globe earth model;

S45 latitude would give a circle of 2π * 6371km * cos 45°= 28300km = 17600 miles,

S60 latitude would give a circle of 2π * 6371km * cos 60°= 20000km = 12400 miles.

In the flat earth model;

S45 latitude would give a circle of 2π² * 6371km * (180°-45°)/180° = 94308km = 58600 miles,

S60 latitude would give a circle of 2π² * 6371km * (180°-30°)/180° = 105000km = 65000 miles.

“Konyukhov came through it all unscathed, returning to King George Sound at 02: 56:50 UTC (10:56:50 WST) to record a time of 102 days 00 hours 56 minutes 50secs for this 16,400 mile circuit of Antarctica.”

The race data clearly proves a globe earth.

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Mitosis in a prepared microscope slide

A long while ago (late 70’s) in high school, I was observing a prepared microscope slide on a microscope. We had to draw a picture of a cell. Like finding a 4-leaf clover, I stumbled over a cell frozen during a mitosis. It looked like the phase 4 or 5 in this picture:

The teacher didn’t believe me so I made a more “normal” drawing!

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Point to point wiring with magnet wire

I’m currently rewiring a part of the Monsputer’s CPU board that was implemented with several patches. I’m reusing an Atmel CPLD used for another board. A problem with this chip: it’s a TQFP package. Without a PCB, it’s difficult to connect to the pins … or maybe not.


With common tools and a steady hand, it’s possible to connect very fine magnet wires to the pins. A soldering iron with a needle tip, some tweezers, a magnifier (or a stereomicroscope), some liquid flux, an x-acto knife. Some spools of enameled wire (#36 for signals, #26,#24,#22 for power), some tinned wire (#32,#36) for direct connections. The flux is an essential ingredient to a good solder.


Here is the culprit, with many connections made already:


To connect to the pins, the insulation on the wire must be removed. For convenience, we allow two ends when finishing a net and beginning another: about 5 mm of nude copper. When the current net is completed, an half is used for the end of the current wire, and the other half is used for starting another net. In middle net points, we remove 3 mm of insulation. For the TQFP package, we make all nets ending on the TQFP. Instead of 2.5 to 3 mm, we only need about an half of a mm.cut-diagram2

To cut the insulation, we do 8 cuts to scratch the enamel. While there are enamels that melt for soldering, this may cause problems. The 8 cuts are done with a hand held x-acto or similar knife. Here, the x-acto is shown in 2 positions.cut-diagramBefore soldering to the TQFP, the exposed copper wire should be tinned. With a bit of flux, a steady hand (“doigts de fée”), place the wire end on the TQFP pad, heat the pin and the connection is done!

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FE/GE experiments: air against vacuum

One of the flat earth arguments is that we can’t have a pressurised region and a vacuum coexisting side by side.

It would be possible to replicate in small scale the gradient effect of the atmosphere. Inside a vacuum chamber, we put a rotating container with an opening in the center. We make it spin, so the centrifugal force will keep the air inside the container. If we make the vacuum, we would be able to get the air against the vacuum.

Of course, for now it’s only theoretical, since there is no scientific interest except for teaching or demonstration purpose.

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FE/GE experiment: water clinging to ball

In the flat earth/globe earth “debate”, the flat earthers say “water doesn’t cling to a ball”.

A possible way to prove that water can comform to the exterior of a sphere is to use a Van de Graaff generator upside down so the electrode can drop water in a safe way. The high voltage should be able to hold the water on the sphere.

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