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Re: Seeking schematics/plans for decimal to binary (microswitch/relay) selector/controller

I am interested in building a "selector" gadget for devices that take

>jumpers >to select a program, such as this game cartridge where you have 5 >jumpers >to select program #0-31 (the jumpers represent the binary number): > >
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> >The selector would have two 7-segment LEDs that display the currently >selected program number (0-31), and a couple pushbuttons (+/-) that >let you >increase/decrease the program #. The device translates the number >into >binary and turns on/off the appropriate switches or relays which are >attached to the jumpers on the device (ie the above game cartridge).
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If you want to do it in hardware you could use a couple of 74XX193\'s
feeding an EEPROM with a lookup table burned into it as described
below. 

You\'d also want to decode 32 and 128 (overflow for your setup and
underflow for the counter) and use those decodes to generate a reset
pulse which would send the counter and the displays back to zero.
Reply to
John Fields
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You could use a multi-turn potentiometer. A 10 turn pot would make it much easier, since a selection would then be 14°, which would be much more manageable. Using a 'heavy' knob, which would keep spinning due to angular momentum would make it less tedious to dial from 0 to 255.

One issue with this approach is that it might change if it is near the cutoff point, or worse, oscillate between two due to vibration.

Another issue has to do with my microwave (that I just dumped today because of terrible interference problem with cordless phones) which had a a spinning knob to select the cook time. It was a free spinning dial, which would change more quickly depending on the velocity of the dial. It was very tedious to use, so while the interface might seem like a good idea, it probably isn't.

(The uWave was a Panasonic 1300W oven, for those who wish to avoid interference. I even went out and bought a 5Gig phone to avoid it, and it actually interfered with the new phone. I'm surprised it passed FCC testing. It must have been spraying EM all over the airwaves to interfere with a 5Gig phone.)

Regards, Bob Monsen

Reply to
Bob Monsen

Sounds like a bad seal implementation, hard to get more than 1uW/cm^2 even right on top of the panel or door. Interference that bad could only be caused by insufficient or severely imbalanced tightening of the 'tron' bolts and gasket.. or it may have been something awry with the input filter on that crummy little 36KHz inverter, if it had one of those.

Reply to
Fred Bloggs

I use Comcast (I know, but it's what's available) and I see only a few spam posts a day here, mostly cheap shoes and that damned islamospammer, with the odd update on the old chain letter.

Reply to
Stephen J. Rush 

--
I guess you missed this part about using a single-turn pot and an
ADC:

"However, if you used only the 5 MSBs, that\'s 330°/31 steps, which
will get you 10.6° per step, which is eminently doable." :-)

That would also get rid of the tedium of getting to a distant
channel and the expense of the 10 turn pot.
Reply to
John Fields

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