Some of you may remember I had a dream last year (more a revelation actually) when lying abed about the QDX.? I realised that it had no physical controls and operated purely under software control via the USB link.? This meant that it could be located remote from the operating position at the bottom of the garden, avoiding long runs of coax into the house and in a quieter area electrically.
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Well, my dream has come to fruition.? In fact I now have a Software Defined Receiver and a QDX at the bottom of the garden.? It's taken a few months of, sometimes faltering, progress to get to this, but, finally, I have got a system that's working.
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One thing that I realised I needed was some telemetry/remote control so that I could at the very least switch either the QDX or the SDR on and off.? I had a vague idea that an Arduino would do the trick and after a cursory glance at the specs I shelled out ?19 odd to buy a Uno. Once I plucked up enough courage to plug it into my PC, I found it was pretty easy to get going. The simplified C++ language used was not difficult to get my head around.??
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For the PC end of the job, I needed something to read the serial data and display it appropriately.? Twenty odd years ago, for this sort of thing I successfully used the Borland Delphi development environment which utilised an extended version of Pascal. That time was when we called things "programs" and "apps" hadn't been invented!? When I looked at getting the up to date version of Delphi, I was shocked to discover the cost was way beyond my pocket.
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I eventually stumbled on Microsoft Visual Studio and was delighted to find they offer a free "community" edition for small scale and non-commercial developments like mine.? It offers the way to build an app using all the usual controls familiar to Windows users and to program in several different languages. As I had a lot of experience in the final years before retirement of using Visual Basic for Applications with Excel, I chose the Visual Basic language to develop my Telemetry Windows Form App.
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Then followed a lot of trial and error (mostly error!) trying to get the Windows Forms App to accept data gathered from the Arduino over the serial USB link.? I eventually found the way to do it was for the PC to send a single polling byte to the Arduino every 80mS via a timer event, to which the Arduino sent out 12 strings of data with the telemetry readings.? The polling byte varied depending on the control command, with 5 bits of on-off control used.? Bit 0, for example, turned the SDR on and off.
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For anyone interested, I have made a Youtube video about my "bottom of the garden" installation.? This includes a demonstration of the Windows Forms App (near the end) showing what facilities the Arduino provides.
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The Youtube video is here: https://youtu.be/GPlvy_8QNrw
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Peter Lee
G3SPL
