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Controlling digital pots via computer

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Rov

New Member
Does anyone know where I can find diagrams for multiple (4 or more) digital pots controlled by a computer via USB or RS-232.

I have motor controllers that use pots to control the speed of a motor I would like to control them using my computer.

I have never used a digital pot before, is this the way to go? If anyone can think of a better solution without me having to buy new controllers as I am a broke college student. Thanks
 

3v0

Coop Build Coordinator
Forum Supporter

3v0

Coop Build Coordinator
Forum Supporter
I hate these far out questions. RS-232 has nothing to do with digtial pots. Ask
one question or the other...
Because people see inexpensive tenchnology everywhere they assume it must be easy. We are seeing this a lot with the recent generation of young adults. They want to build custom MP3 players but if it requires programming or a solder iron it is too difficult. As is getting out of bed.

3v0
 

crutschow

Well-Known Member
Most Helpful Member
I hate these far out questions. RS-232 has nothing to do with digtial pots. Ask
one question or the other...
He was asking if there's a way to control digital pots from an RS-232 or USB port. That seems a fair question to me, even if it shows a lack of understanding (but to elucidate such a lack is the purpose of this forum). I've seem many farther out questions then that here. If you hate those type of questions, then I suggest you only answer those you don't hate, rather then implying that the person is asking a dumb question.

To answer the question, you could perhaps, bit-bang a parallel printer output (if you have a computer that still has one) to control the I²C or SPI serial interface that many digital pots use.

If you only have a serial port, than you could use something like this Spi Converter to convert from it to SPI. There are also a USB to I²C adapter USB to I2C Adaptor.
 

colin mac

New Member
He was asking if there's a way to control digital pots from an RS-232 or USB port. That seems a fair question to me, even if it shows a lack of understanding (but to elucidate such a lack is the purpose of this forum). I've seem many farther out questions then that here. If you hate those type of questions, then I suggest you only answer those you don't hate, rather then implying that the person is asking a dumb question.
I rather imply the person is asking a dumb question. I see these dumb questions go time and time again unanswered.
If one understands RS-232, then one understands what RS-232 can do and whether it can control digital pots or not.
If the OP doesn't understand RS-232 or digital pots, the OP should ask about RS-232 or digital pots, not lump the two together hoping a for a total solution.
 

Rov

New Member
-Colin mac
If I knew I would not be asking, now would I? Instead of discussing how dumb my question is you could contribute something useful to this thread and enlighten me on using a digital pot with a computer since that was what I was asking. I asked about RS-232 because that is what I have readily available.

-3v0
Thank you for the links, they were very helpful.

Because people see inexpensive tenchnology everywhere they assume it must be easy. We are seeing this a lot with the recent generation of young adults. They want to build custom MP3 players but if it requires programming or a solder iron it is too difficult. As is getting out of bed.
I am using this for a college project and it does not matter how difficult it is, I am willing to work hard on it. My only limiting factor is money.

-crutschow
Thank you.
 

Leftyretro

New Member
-Colin mac
If I knew I would not be asking, now would I? Instead of discussing how dumb my question is you could contribute something useful to this thread and enlighten me on using a digital pot with a computer since that was what I was asking. I asked about RS-232 because that is what I have readily available.

-3v0
Thank you for the links, they were very helpful.



I am using this for a college project and it does not matter how difficult it is, I am willing to work hard on it. My only limiting factor is money.

-crutschow
Thank you.
Your question was far from dumb and some people here just like to make life hard for the newbies I guess.

Well one way would be to get a micro-controller board that uses RS-232 or a USB serial converter to talk to the PC. I've been using Arduino AVR boards recently and found them inexpensive but pretty powerful and lots of support help from their forum.

Here is one that uses USB:

SparkFun Electronics - Arduino USB Board

Here is one I built from a kit that uses a RS-232 serial port:

Freeduino Serial v2.0 board KIT Arduino Duemilanove Compatible

These boards are programmed with a free open source multi-platform IDE using C or C++ in a simplified manner with lots of library support. Most digital pots use the I2C or SPI serial interface standard and the Arduino can handle both. Here is a users contribution on digital pots:

http://mrdoall.dnsalias.com/wiki/index.php/X9241A_-_Digital_Potentiometer

And of course you will have to decide it the microcontroller will be free standing or if you will be writing a user application on a PC and sending commands to the Arduino/digital pot.

Good luck and keep us posted on your progress and choices.

Lefty
 
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