digital potentiometer

[jeff1500]

Does anyone know how to use one of these?

MicroChip 8-dip potentiometer

It's Digi-key P/N MCP41010-I/P-ND

My big question is, Does it need more cicuitry to make it work or is just the chip enough?

I looked at some Maxim chips and I thought they wanted a bunch of other components to make them go?

 

[MrAl]

Hi again Jeff,

How ya been?

I took a quick look at that chip, and
if looks like you have to have a device
to send it a serial digital code in order
to change the resistance of the 'pot'.
This of course means it's mainly for use
within a system that probably already has a
microprocessor at its' heart. There might
be a way around this using maybe a
serial output shift register, but i think
it would require a few more chips as well.

Can i ask what you intended to use this for?

Take care,
Al

 

[jeff1500]

http://edusite10.tripod.com/led3/max757/max757.html

I made this kind of funny looking thing with a dimmer on the end. I really like it. The dimmer lets me adjust the light to just the right conditions. The dimmer range is from about 3.0 to 3.5 volts. I set it so the leds get a max current of about 25 mA each. The step-up works well too. It doesn't care much about what I use for batteries. Both Nimh and alkalines work well.

I've been wondering if I can make something now with surface mount parts and maybe a digital potentiometer.

Also, didn't you once mention making an LS simulator out of maybe a diode and a resistor for testing purposes. What were the parts? That might be another thing to experiment with.

 

[MrAl]

Hi again Jeff,

That's a very nice little circuit.
It looks very safe for the LED's
and the adjustable brightness gives you
much longer run time i bet at lower settings.

I dont think you will want to use that
digital pot because it will draw in too
many other support chips. I like the
idea of just using a pot though, and you
can find one of those small ones that
should be smaller then an ic chip, or maybe
about the same size as an 8 pin dip package.
Ever see those kind of pots? They adjust
with a screw driver, but they turn pretty
easy so even a key would work i bet.
I was going to put one on my two LED light,
but instead i ended up using a dip switch
with about three different resistors that
get switched in or out. If you work the
resistor values right, you can get 16 different
levels with only four resistors and four
switches, although i guess you dont really
need that many levels :-)

The LS simulator was just made by connecting
three 1N4001 diodes (or 1N400x diodes) in
series and then a 1 ohm, 1/2 watt (or better)
resistor in series with the diodes.
The LS anode is then the anode of the top
diode, while the cathode is the free end
of the resistor. That's the simplest
simulator and works fine for testing circuits.
The voltage is just a hair under the real
LS voltage, so if you want you can add
a Schottky in series with the other three
diodes also, but i didnt find it that
important during all of my tests.

Take care for now,
Al