Previously I had written up on how I had used gnuPlot to graph my house temperatures.

Here is the current outside air temperature for Busselton - well, at least at a DS-18B20 sensor located near a west wall of the house:

Last 24 hours:

Last Week:

For some time, I have wanted to actually test a photovoltaic (PV) panel.  I would like to measure the panel temperature and power output, along with how the power changes with the panel angle etc.  I needed to purchase one for my remote bush weather station project (more on this project later), so this is a great opportunity to run these tests.

Early in the month, I managed to read my first DS-18B20 temperature sensor.  Over the intervening few weeks, I have been experimenting with using a Python script to read up to ten sensors at a time, and storing the temperatures in a MySQL DB.  Here is a close up of a bank of 11 x DS-18B20 temperature sensors.

It will also display one of the temperatures onto a Nokia 5110 LCD screen.  You can see the bank of 13 x sensors off to the right hand side:

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:

There are a number of ways to read a 1-wire DS-18B20 temperature sensor via a Raspberry Pi.  As of December 2012, the Wheezy OS contains a kernel loadable module that allows you to directly read them.  At the moment, I won't go into how to do this, as you can read some other peoples in-depth web pages on how they have done this:

You can either download a fresh Raspberry Pi image from here: http://www.raspberrypi.org/downloads

or you can upgrade the OS software view running the following:

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.

I have written previously about logging data from a West facing window.  After emailing and comparing notes with a friends Garmin GPS readings, I thought it was time to gingerly take the GPS-RaspberryPi outside for a real world test run.  Luckily the external antenna comes with a generous 5m long cable, so I could put the unit in the shade and the antenna up on the fence line.

The results where better than I expected:

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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