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A WiFi-Controlled VFO

A WiFi-Controlled VFO

Now that I have placed a DDS on a board with Wireless connectivity, it is only obvious to set it up as an AP Web Server and allow remote control via a ‘soft’ user interface…

When I first started to play with the AD9850 DDS, I made some beacons and wrote the Kanga VFO demonstrator code (as application code to support the Kanga / m0xpd DDS shield). Well, now I’ve produced this new internet savvy AD9834 DDS board, I’ve followed the same pattern; I’ve done the beacon thing and now – in this post – I’m covering the VFO. Only, of course, this VFO won’t have physical knobs and buttons like its predecessor. Understand, it could have all the physical controls if you wanted it to – but that’s not the point. Instead…

When  the new code fires up, the ESP8266 sets itself up as an access point and offers a new wireless network:

which you can join from any phone, tablet, computer or similar wireless enabled device. This will provide the interface to the VFO. The network name ‘m0xpd Kanga DDS 94TD’ is formed of a generic part (‘m0xpd Kanga DDS’) and a four character index associated with the particular board (such that two VFOs in the same area could operate independently).

Opening a browser and going to the VFO’s ‘web page’ will open the simple control interface seen below, which reports the frequency at which the oscillator is running, offers ‘buttons’ to adjust the frequency and ‘buttons’ to change band:


The picture above is a photo of my iPad mini screen, controlling the VFO. I’ve added the red annotations to make it clearer for you.

The web page is generated entirely by the m0xpd / Kanga ESP8266 – AD9834 board – the iPad is just interpreting it (as HTML).

Clicking on any of the ‘Adjust Freq’ hyperlinks will cause the VFO frequency to change according to the label. Clicking on any of the ‘Select Band’ hyperlinks has the obvious effect.

All this is rather dynamic and needs a video to demonstrate (which I haven’t provided) – so here are some rather dull ‘stills’ of the system on 40 metres

and 80 metres…

And here’s a ‘sniff’ of the requests received from the web page of sequential increments and decrements in frequency whilst on 80m, along with the resulting frequencies…

This code will be released as an application ‘demo’ for the new m0xpd / Kanga ESP8266 – AD9834 board (along with a multi-mode beacon).

Of course, the demo code above is intended only as an illustration of what is possible. The rather dry web page could be replaced by an application, written specifically to control a different piece of VFO code, etc.. This is just a start point – but it sure gets me thinking…

There are other exciting opportunities to be exploited via this access point – watch this space!

…-.- de m0xpd