I have been playing around with building and logging house temperatures for a while now.  Previously I had manually created Excel based graphs, but I knew I wanted to generate some gnuPlot graphs and to possibly have a go at sending the data out onto the internet for graphing as well.  I have used gnuPlot previously to plot other data and found it extremely fast, generating 1600 pixel wide graphs of 160K points of data in way under a s

Z280 test board - bottom view of the hand soldered wiring

Side view of the top of the Z280 test board

Front cover of the Z280 Technical Manual - November 1989

Back in 2005 July when I was working on testing a lot of my SWASC boat parts I thought it would be handy in having a +5V and +12V DC Bench-top Power Supply Unit (PSU) handy.  After a bit of hunting around online, I found that I just had to put a load on one of the PSU pins, and it would stay powered up, without a load.

Here are a few notes on how I went about this.

Parts used:

An Acer PC PSU converted to a bench 5V & 12V power supply

I lived close to and worked in Silicon Valley, California for three years in the heady days of the early 1990's.  It was an exciting place to work in and explore.  My work allowed me time to visit various different companies and places.  One that I managed to visit was Zilog - the maker of the Z80 CPU chip.  My first computer - the Tandy TRS-80 Model 1 (it was the first computer one could purchase in Western Australia back in 1978 or '79).  I fell in love with the assembly code, writing my own and extending other peoples code.

This shows how the GPS data has varied over time.  Each colour represents 383 seconds.  A lot of data is layed over top of previous data.

This is a close up of the Fence GPS data and shows the number of satellites used for each fix. 

When dealing with decimal Lat/Long, a change in the 5th decimal place results in the following changes:

a 0.00001 change in Latitude results on a change of ~ 1.11m

a 0.00001 change in Longitude results on a change of ~ 0.926m  (at my location)

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