how to control 555 resisters with PIC

[Acetronics2]

If you really wanted to get crazy, you could easily drive an R/C aircraft servo to turn a rotary switch connected to a bank of capacitors (ya know, ka-chunk, ka-chunk, ka-chunk) and another servo to drive a linear pot. Drive servo's is easy with a PIC also. At least you'd have something mechanically silly to watch, something a tad bit over engineered.
JDG

Hi Skimask

before ... just learn how to fly models with old non proportionnal radios ...

THEN you can talk about all that ...

Ah ... look at the little ( humour ) difference between AD7376 and the XICOR X9xxx ...
One can be used ... and the other NOT here.

Alain

Hi, KB3

As the capacitor have one terminal to be grounded, you can use Mosfets like 2N7000 or BS 170 instead of the relays.
But it will introduce a small parasitic capacitor ... if it doesn't matter, that would be simpler to build.

Alain

[Luciano]

Hi,

Same problem when the TV remote controls were introduced.
To replace the potentiometers, ICs + fixed value resistors
were used.

From the 4000 Series CMOS:

Quad Bilateral Switches
4016, 4066.

CMOS Analog Multiplexers/Demultiplexers
4051, 4052, 4053.

* * *

About the 4016:
http://www.doctronics.co.uk/4016.htm

* * *

Modern Digital Potentiometers:
http://www.maxim-ic.com/DigitalPotentiometers.cfm

Best regards,

Luciano

[skimask]

Hi Skimask
before ... just learn how to fly models with old non proportionnal radios ...
THEN you can talk about all that ...
Ah ... look at the little ( humour ) difference between AD7376 and the XICOR X9xxx ...
One can be used ... and the other NOT here.

Alain

Hi, KB3
As the capacitor have one terminal to be grounded, you can use Mosfets like 2N7000 or BS 170 instead of the relays.
But it will introduce a small parasitic capacitor ... if it doesn't matter, that would be simpler to build.

Alain

Who says I haven't used non-proportional radios, with them ol' 45v batteries in the TX's...big ol' switches, big ol' boxes...etc.
Besides that, I've got a pilot license now. I've still got to train my arms to be a little more proportional on those crosswind landings

AD7376 - X9xxx - One can be used, the other can't.... Looks to me like both could be used.
What am I missing?


As far as using the 2N7000 to switch the cap's in and out...
Q: Even if you drive the '7000 fairly hard, it'll still have a couple of ohms across the drain-source. Won't that mess with whatever cap it's connecting into the circuit like the 4066? I know the 4066 is a lot worse and it affected my circuit.

JDG