[Elecraft] Sorta OT - assistive technology assistance needed

[Walter Underwood]

Funny, I just realized I was misreading “OT” as Occupational Therapy. Our son just finished
OT grad school and is studying for the board. Of course, assistive tech is a big part of
occupational therapy.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Jan 9, 2019, at 5:42 PM, Dave Fugleberg <dave.w0zf at gmail.com> wrote:
> 
> I usually like to build stuff when I can, but I have to agree with the
> others who suggested a commercial mixer. They are cheap and work well.
> I recently bought a small behringer USB mixer for under 50 bucks for a
> project at work. It acts as a USB sound card, so you can mix audio to or
> from the PC with other sources. You can adjust levels, equalization, and
> position (left/right) for each source.
> I doubt one could homebrew an equivalent unit any cheaper.
> Good luck with your project! I’m sure your friend will appreciate it.
> 
> On Wed, Jan 9, 2019 at 5:30 PM Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
>> James,
>> 
>> There was a homebrew headphone mixer in the ARRL Handbook sometime back
>> - simple, with op-amps to isolate the sources.
>> 
>> However with the advent of 2 to 5 input mixers being available in the
>> $20 to $60 range (see Amazon), it seems foolish to consider building
>> your own - drilling the enclosure for the potentiometers and jacks,
>> building the board, mounting things, etc. will take more time and effort
>> than is reasonable unless you really like doing those things - and it
>> will likely cost more than buying one already built.
>> 
>> The nice thing about a mixer is that you have control over the level of
>> each input as well as an overall output volume control.
>> 
>> 73,
>> Don W3FPR
>> 
>> On 1/9/2019 6:03 PM, Richards wrote:
>>> Good Day.
>>> 
>>> Background:
>>> 
>>> I am assisting a blind ham who also suffers some hearing loss.  I
>>> suggested using headphones to attenuate ambient environmental noise as
>>> he operates.  The rub is, he needs to hear both his receiver AND his
>>> computer (which provides audible feedback when logging contacts and
>>> performing other duties.)
>>> 
>>> Question:
>>> 
>>> Can anyone suggest a simple passive (or active) mixer circuit schema I
>>> can build for him to safely mix audio signals from his transceiver
>>> headphone jack with audio signals from his computer sound card headphone
>>> jack?
>>> 
>>> Discussion:
>>> 
>>> While there are multiple commercially produced simple and complex mixing
>>> products in the marketplace, I would prefer to build an inexpensive,
>>> small footprint solution we can easily incorporate in his station to
>>> minimize clutter and the number of cables, jacks, and controls -- he
>>> contends with plenty of that already.   I suppose one solution might be
>>> a simple Y-adapter cable, but that seems too easy and I wonder whether
>>> we should isolate the signals and/or grounds in some way?  (e.g., I do
>>> not wish to cause any "Pin-1" grounding issues, and etc.)
>>> 
>>> Any traction?   Can anyone point me to an appropriate circuit schematic
>>> or other resource?  I don 't mind doing homework, and while I enjoy
>>> building stuff and I am familiar with the basic concepts involved,  I
>>> could use a leg up on this project, especially to keep it simple and
>>> easy to build and implement. Please reply off list if this question is
>>> too far off topic, although I suspect there are many hams who might be
>>> interested in the result, besides similarly situated disabled operators.
>>> 
>>> Thank you -  James - K8JHR -
>>> ---------------------------------------
>>> 
>>> 
>>> 
>>> 
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