All posts by Graham Cottew

Graham Cottew's career has seen him work in a wide range of disciplines and industries, but as Zendata takes his career into a new phase, he still sees himself principally as an applied mathematician. "Mathematics allows you to model and explain events in the real world, from simple to highly complex, and subsequently to predict what will happen next. "The interaction between science and nature is where Zendata works", according to Cottew, "and as substantial computing power has become more and more affordable, we're now able to build some very capable machines which can monitor many events and constantly readjust the settings of a machine to maintain optimum performance." "Computers can monitor a set of processes flawlessly, and thanks to recent advances such as neural networks and fuzzy logic, computers are now getting to the point where they can take on a character of their own, making decisions and value judgements more akin to those made by human beings." "Indeed, computers can now administer a set of rules well enough to approach and in many cases surpass that of a highly trained human being." "A perfect example of this type of process is in a state-of-the-art jet fighter plane. Humans don't really fly these planes any longer, because they simply don't have the ability - the movement of the ailerons,rudder and other surface controls are controlled by computer and the pilot really just chooses the direction via a joystick while the computer ensures that the pointy end is at the front! These planes are inherently unstable and would fall out of the sky if the computer ever failed. Essentially, they're flown by computer and guided by humans." "Fuzzy logic is adaptive and hence it is very useful in many of the applications we need to develop. In our robotics work, for example, " said Cottew, "we have used fuzzy logic to learn the behavioral characteristics of a piece of physical equipment, then adapt its control algorithms to suit that equipment as it ages and as its environment changes without human intervention." "Our real-time control software was developed with this in process in mind - not just to control the existing applications, such as our Automotive Quality Assurance System, but to allow engineers to quickly develop more advanced control processes." Graham completed his Bachelor of Science degree in Applied Mathematics (Distinction) at Monash University in 1972, a Graduate Diploma of Meteorology in 1973 and a Graduate Diploma of Data Processing, also from Monash University in 1975. Since that time Graham has specialised in implementing diverse applications of science and information technology in many industries. The nature of Graham's work is such that in many cases it is subject to non-disclosure agreements and in some cases far more onerous conditions related to national security, and hence many areas of superbly implemented applied technology must be overlooked in this document. In general however, the only constant in Graham's career has been the application of bleeding edge technologies to achieve extraordinary results. By working through his own consultancy, Graham has had the opportunity to work in a variety of fields as the client listing below clearly demonstrates. An articulate communicator, Graham has written and conducted workshops and seminars on a variety of technology-related subjects, and is an occasional columnist in the computer press. Membership of Professional Bodies Member of Australian Computer Society Fellow of Royal Meteorological Society Member of Wireless Institute of Australia Australian Telecommunications User Group Telecommunication Society of Australia IEEE Software Engineering Group

Touchscreen for my Raspberry Pi

Finally found a use for the latest in a collection of Pi’s – grabbed a 7″ touchscreen for the Pi 3 from Element14 https://www.element14.com/community/docs/DOC-78156#comment-106928 and connected it up in a few minutes.

Here is the rear view with the Pi attached above the LCD controller.

The screen actually behaved and looked better than I thought it would.

The only drawback is the rather cruddy virtual keyboard – I am sure that someone will eventually improve on the UI of the only option that so far I am aware of,  and is referenced on the official site.

Anyhow, the use I have in mind is an RF direction finder.

I recently participated the @sdr_melbourne foxhunt located in the Westgate Park. Most of our targets were in the 433 MHz ISM band and I had built a small portable three element yagi for the DF role. I designed it for maximum back to front ratio, and minimal side lobe radiation, both desirable characteristics for direction finding.

To be continued …

 

Putting radiation into perspective

Radiation levels are not well understood by the general public. I am amazed at the levels of ignorance and misinformation surrounding radiation, it’s sources and what is safe and what isn’t.

This excellent chart courtesy of the XCKD team helps educate and enlighten. Please have a look at it and know what may be harmful for you and what isn’t. You will be surprised!

Outernet

Outernet provides a free service with global reach designed to enable low cost connectivity to communities that would otherwise be out of touch.

This post is almost completely sourced from the Outernet web site. My Outernet kit just arrived and these are the components:

Outernet kit contents

Go to their site or read on here to see how it work and what is involved.

Our filecast differentiates itself from a traditional broadcast by sending information as data files, so content is no longer limited to video and audio. Now, any content format can be sent over a radio signal. Receivers automatically cache these files locally, so users can enjoy flexible, on-demand access to content.

With the global reach of satellite broadcasting, this system is paving a new way to distribute, access, and consume content.

Read on to learn more about filecasting, the Filecast Center, or applications of technology. Visit our product page to learn more about our receivers.

LIFE CYCLE OF A FILE

TRANSMISSION

A file is converted into a radio signal and transmitted around the world over satellites.

This process is similar to what happens with satellite radio, but the file can be in any format.

Read more about the signal.

 

DEMODULATION

The receiver catches the radio signal and extracts the original file.

Once extracted, the files are automatically saved on the receiver’s internal drive.

Read more about the hardware.

ACCESS

The receiver acts like a local server for the saved content, and emits a WiFi hotspot.

Users can connect to this WiFi with any device to access the saved content.

Read more about the user interface.

SIGNAL

Our signal is broadcast over three Inmarsat satellites, offering coverage on continents and on the open seas. These three birds are:

  • I-4 F1 APAC (Asia-Pacific), at 144-degrees East
  • Alphasat, at 25-degrees East
  • I-4 F3 Americas, at 98-degrees West

Our frequencies are:

  • APAC: 1545.9525 MHz
  • Alphasat: 1545.94 MHz
  • Americas: 1539.8725 MHz

Bitrate is about 2kbps, or 20MB of content per day.

Outernet L-Band hardware can also be used for Inmarsat reception, including SafetyNET, EGC, and AERO.