View single post by Slider2732
 Posted: Aug 26th, 2012 10:28 AM
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Slider2732

 

Joined: Mar 3rd, 2008
Location: Muskogee, Oklahoma USA
Posts: 349
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By the way, welcome to the group !  :biggrin:

Being rusty is well understood..after all, i've only just returned to these 1088's myself after your first post. I'd say you could do with buying a few radios, do the modifications, try it and if you see something else in the datasheet, change that too :)
Buying a few would also mean that if you come up with a good casing etc, you could hand them out to others who are interested or trial different ideas without blowing up 'the' radio. From experience, it's better to have half a dozen on hand, than to make a mistake mid-evening and realise the store has now shut.

Pot wise, you could put a 500ohm resistor on, could then change that to 100ohm and then to 1K. But I would recommend using Freecycle or visiting thrift stores and gaining some freebie parts. After all, that would be in keeping with the costs of this project.
Within my usual electronics builds now of efficient energy devices (uA LED oscillators, Tesla towers etc) i've found the circuitboards from old CRT TV's/monitors, 1990's hi-fi's, telephone answering machines, satellite receivers etc to be hugely valuable for any parts needed. Practically every commonly found circuit online can be built for nothing.

For the 555, you could run the circuit at 5V from a converted PC power supply all day, by using 3x 1N4007 or similar diodes in series from the Positive supply line. Each dropping about 0.7V would see the circuit run at 2.9V (check with multimeter for exact drop). You'd then run the 555 from the 5V without issue.
Alternatively, a wall adapter, like 9V could be used and then put a 7805 voltage regulator on that output. That would again bring things to 5V.
It's all very easy 10 minute stuff you'll be glad to know, but is where the stock of junker parts comes in handy :)


Last edited on Aug 26th, 2012 10:30 AM by Slider2732