Homebrew PCBs

It would be nice if you could put it into the file or photo section of the group. Thank you.

Jean-Claude, Switzerland

  ----- Original Message ----- 
  From: Roger Blair 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Saturday, May 01, 2010 5:36 PM
  Subject: RE: [Homebrew_PCBs] Re: Speed control for laminator motor


    
  I am interested in this also, if you don't mind sharing.

  Thanks,

  Roger

  From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of awakephd
  Sent: Friday, April 30, 2010 07:38
  To: Homebrew_PCBs@yahoogroups.com
  Subject: [Homebrew_PCBs] Re: Speed control for laminator motor

  Richard, what kind of circuit do you have in mind for the PWM? If you're wanting to do something with discrete ICs rather than a
  microprocessor, I put together a PWM controller that allows for variable frequency as well as variable pulse width (true PWM) -- and
  it only requires 2 op-amps or comparators, so it can be made with a single chip (not counting the drive circuitry). This may be a
  common design -- I may have re-invented the wheel! -- but I couldn't find anything like this when I was needing this circuit. I
  specifically wanted something that generated true PWM, but allowed me to vary the frequency so that I could choose the best
  frequency at which to run for a given application. Let me know if you're interested.

  --- In Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com> , Richard Spelling <rls@...> wrote:
  >
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  > Went to bed tired and annoyed I couldn't easily find a slower gear motor
  > for the laminator.
  > 
  > Dreamed about building a magical speed controller that would let me run
  > the existing motor infinitely slow.
  > 
  > Realized I could use "temporal kinetic and thermal stabilization" since
  > it's a worm gear motor.
  > 
  > I.E., I build a standard PWM controller but set the frequency real
  > sloowwwwww.
  > 
  > Imagine having the speed turned down real low. Along comes a pulse. The
  > motor spins up and turns the worm screw a revolution or two, then spins
  > down. The board advances a fraction of an inch. An in-determinant amount
  > of time later, along comes another pulse.
  > 
  > Yes, it's "jogging" the board forward and not continuous motion, but
  > between jogs it sits between the rollers long enough for the heat to
  > transfer through the paper.
  > 
  > I'm thinking about 10Hz.
  > 
  > Whatcha think? Just another crazy idear from Richard?
  > 
  > Now I just need to build the board.
  > 
  > Wait a second, I need my laminator to build the board to fix the laminator!
  > 
  > 
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