Analog Cpu.

Felino · Post by **Felino** » Sun Sep 23, 2007 3:45 am

While i am waiting for my new 3W led to come in the mail, i was digging through stuff and i found a old but working voltage meter, that had been ripped out of somthing at some point.

Could i rig this up somehow to run as a cpu useage meter? It measures from 0-10 vdc, it has a 10K resister (5W) in series, but i could remove it. The coil has a resistance of 178Ohms, how could i do this?

If i used serial i would have 10v, but does that help?

The only.
-Fel

timmeh87 · Post by **timmeh87** » Mon Sep 24, 2007 5:16 pm

at the end of the day you are going to have to write some software to check the cpu usage and output it to a port.

you might be able to just provide a PWM signal with a parallel port or something, and use a low-pass filter (resistor and a capacitor) to create a makeshift analog output

otherwise you could always use a PIC and a serial port

THON · Post by **THON** » Mon Sep 24, 2007 8:13 pm

timmeh87 wrote:at the end of the day you are going to have to write some software to check the cpu usage and output it to a port.

you might be able to just provide a PWM signal with a parallel port or something, and use a low-pass filter (resistor and a capacitor) to create a makeshift analog output

otherwise you could always use a PIC and a serial port

Never cease to amaze me with your infinite wisdom...

Felino · Post by **Felino** » Tue Sep 25, 2007 12:27 am

Sarchasm?

I was thinking of sorta what you said, pwm into a cap, but i was hoping for a cleaner option. for that sort of coil, without the resister, what actually drives it, the voltage or the current?

timmeh87 · Post by **timmeh87** » Tue Sep 25, 2007 5:06 pm

cant tell if its sarcasm

its the current that is directly related to the coil displacement, i think, but voltage is directly related to current through resistance.

so i think, for simple r-c circuits you could say either of them.

Felino · Post by **Felino** » Tue Sep 25, 2007 6:00 pm

So, say i ran it as pwm pulses, would i need much in the way of jerkyness? If i ran a cap across the coil, it would smoothen it out, yes / no?

And, i wouldn't really be pulling more than say 60mA, that would make it able to run off the serial / paralel ports happily?

timmeh87 · Post by **timmeh87** » Wed Sep 26, 2007 6:37 pm

http://upload.wikimedia.org/wikipedia/c ... filter.svg

put the pwm signal on Vin, and if you frequency is high enough the voltage on the capacitor should be completely analog and linearly related to duty cycle.

most ports should be able to do 60mA