Wednesday, June 4, 2014

Minima - New Positive Progress

The last few days I have be struggling with my least favorite Homebrew build type of circuits, and that is the Audio Modules for the Minima Transceiver. I general, I just do not like to build Audio circuits.

Originally when I started the Minima Build, I was planning to build each schematic section as separate modules. For the RF sections that approach has work well. My original attempt to build modules for the Audio sections failed because they are somewhat dependent on each other, and therefore many interconnecting pins were going to be necessary to connect everything together. My original thought was to arrange the five Audio modules into a "checker board" with edge header between each. The first layout with headers on several sides of the modules eliminated their general use as building blocks for other projects. I wanted an easily adaptable modules for future projects. Because the module approach became to complex and therefore after several days (weeks) I abandoned the Module approach for the Audio Circuit - FAIL.

I collected the modules together into a single complex layout, but thats is where it sat for several weeks, although I publish blog posts with photos, diagrams, and discussions about the project. I was still not happy with the design or the approach.

But I needed to get something done to show progress on my Minima Build.  Three days ago, I decided to Build the Audio Board with the Toner Transfer Method (the same as with all of my modules). The Audio Board was going to be about 2.5x5.0 inches with 84 hand soldered via's. I printed, etched, dilled, and solder wiped the board and got it ready to install the 84 via's. But each time I looked at hand soldering 84 via's the number looked like a bigger task, and my interest diminished. I again abandoned the complex Audio Board, as there has got to be a better way!! - Another FAIL.

An Idea

The solution may be going back to individual modules, but this time I am going to stand-up each module on its edge Header. There will be five modules as described on the original schematic, and one power supply module. The modules will stand on a group of spaced headers on a Audio Mother board. These modules will easily work with ProtoBoards for experiments and testing, and therefore satisfying my original goal for the Minima.

I have now completed the layout for each Module and the Mother Board. The Mother Board is about 1.5x5.0 inches.  Each of the five modules will be 1.0x1.0 inches square. The Relay Module is a little larger.

The Mother Board will contain the Module Headers, Jacks, the edge connector headers for the Digital Controller Board, Tuning Pot, and Volume Control. It will be the "Glue" that connects all of the Modules together.

Mother Board, Five Modules and
a Power Supply Module
These boards will be created using the Toner Transfer Method.

With this new approach, I have a design (with only a few via's) that will hold my interest, and therefore my Minima Project Build should now continue forward. I can build a Module when I have time with very little overhead.

If this prototype works, I may send the design out for professional manufacture.


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