Sunday 20 October 2013

Occam's Dagger

You've heard about his Razor - well now William is tooled up with a new blade - meet "Occam's Dagger"...


It is just as sharp as the original "Occam's Microcontroller" rig, but it packs a much bigger punch in terms of functionality.

Using the extra opportunities presented by the 16*4 alphanumeric display and three push buttons (which could be added to the mix as there were some I/O pins freed up by the display's I2C interface), I've built a menu-driven User Interface. This takes the "root" display from the Kanga Enhanced VFO project, as recently hacked to make a beacon...


and adds Receive Incremental Tuning...


the ability to switch between two "VFOs"...


the choice of CW or CW(Reversed) modes...


band selection (top band through 20m)...


choice of automatic CQ message (CQ, CQ(/a), CQ(/p), CQ QRP and CQ FISTS)...


and keyer speed ("dit" length in milliseconds)...


All of this functionality is controlled with the main rotary encoder and the three buttons...


In normal operation, the rotary encoder changes frequency whilst the left and right buttons move the frequency cursor (to change the digit which the rotary encoder is adjusting). Pressing the "CQ" button initiates an automated CQ call, which can be aborted by touching the key or paddle. Pressing the rotary encoder's push-button invokes menu mode...

In menu mode, the left and right buttons navigate between menus, whilst the rotary encoder selects values in each menu - either adjusting a continuous variable or selecting from a list. Pressing the rotary encoder's push-button exits menu mode.

The rig uses the "stack" of shields  familiar from the original "Occam's Microcontroller" rig...


but, unlike the original rig, Occam's Dagger uses the recently prototyped Sudden Tx shield and a new Rx shield based on g3rjv's "Sudden" receiver, now under development. 

Here's the prototype PCB for the new Rx shield, produced by a guy who was offering a PCB milling service through ebay (seems the service isn't available at the moment - so I can't give you a link)...


More details on the receiver will follow in a later post - suffice to say (for the moment) "it works"!

All of the above was produced to illustrate the principles described in the "Occam's Microcontroller" article, which is an open-source project. The components of the user interface which distinguish it from the previously published rig are shown in the following schematic...


The Arduino sketch which powers Occam's Dagger ("Occams_Dagger_0v1.ino") is available for download here . Copy it if you like or - better still - adapt the methods for use in your own experimental rigs!

I unsheathed the dagger for the first time yesterday afternoon, and answered a CQ from g3mck. Turns out that Gerald (who gave the Dagger 559) was in "Oakham" - not "Ockham", but remarkably close!

You can come and meet Occam's Dagger at the G-QRP Rishworth convention next Saturday - see you there!

...-.- de m0xpd

1 comment:

  1. Hello Paul, We met briefly in front of the Kanga stall on Saturday at Rishworth. I really enjoyed your lecture / presentation and look forward to keeping up with and getting involved in this project. The energy monitoring project I've also taken a serious interest in is here: http://openenergymonitor.org/emon/ Regards, Steve

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