Homebrew PCBs

Stefan,

In the thermostat circuit, I placed a LED in serie with the LED of 
optocupler that drive the gate in the triac. I first power on the 
thermostat circuit and the LED is ON all the time, then, I power on the 
fuser with 220v and the LED begin to off and on slowly. Then, when the 
temperature in the fuser is 160 degree app, the LED turn off and on more 
fast and then maintain the frequency of oscillating. I think that frequency 
is 2 cicles for second.

I placed the temperature sensor of my multimeter in the teflon surface of 
fuser and adjust the temperature to 160º with the variable resistor in the 
circuit.

The main problem with the unit is the number of pass for the pcb. I roll 
slowly the fuser with a bipolar stepper motor but I need to pass 20 times 
the pcb for obtain the result in the photo. With this pcb, I tested to pass 
only 10 times the pcb, but not work, I ever need 20 o more. Maybe the paper 
type?, maybe the roll velocity of the fuser? or the temperature?

Esteban Arias
earias@...


At 12:43 a.m. 14-07-2004, you wrote:
>On Wed, 14 Jul 2004 00:47:14 -0000, Esteban <earias@vertice.cl> wrote:
>
> > Hi,
> >
> > Finally I upload a photo ("Esteban" Folder in photos section)of my
> > pcb with toner transfer method.
> >
> > Thanks to the Stefan Trethan aid, I build a thermostat circuit for my
> > HP 4L laser printer fuser.
> >
> > I am using only free catalog magazine paper.
> >
> > One more time; thanks Stefan for your help.
> >
> > Greeting from Chile
> > (sorry by my english).
> >
> > Esteban Arias
> > earias@...
>
>nice board, clean work.
>You might also want to try out component legend with toner transfer,
>it is easy to do and really rewarding.
>
>I'm glad i could help, and I'm glad you took the little help, added a good
>amount of effort and work, and got a very good result.
>
>I think i will set up a page publishing that temperature controller
>circuit.
>It would be better to add integrating and rate components to make a PID
>controller
>but i think it is hard to adjust for beginners. The simple circuit
>oscillates slightly
>but the temperature does stay within my measuring resolution.
>Maybe i'll add very low hysteresis to keep it from "free" oscillating.
>As it is syncronous to the mains frequency it isn't really a problem.
>
>Esteban, i would very appreciate discussing the performance of the
>thermostat on your
>fuser. I think you have a ceramic heater and can't see when it's on?
>perhaps
>you could connect a test lamp or something parallel to the heater.
>What i'm curious about is if it is oscillating slowly or not.
>We can discuss this off list i think.
>
>
>ST