[DeTomaso] Servo heater control

[David Fisher]

Great stuff, Gary.  Thanks for the ongoing education.

I havent used the Arduino, but I have explored it a little and it looks
like a great and inexpensive development environment.   I havent programmed
a controller for 20 years, but I am tempted.

  I cant take much credit for either the nice machining or the electronics
on this one.   I bought from Servo City, per your previous
recommendation.   I modified their 2 channel servo controller to change
from pots to rotary swtiches and added 2 5v regulators to provide 2A @5V
for running the servos.   I did machine the small arms that attach to the
top of the servo bearing head and parts of the bearing assembly to replace
the stock nylon bushing.

http://www.servocity.com/html/servoblocks.html

http://www.servocity.com/html/dual_servo_driver.html

Given that the servo blocks provide a good strong bearing to handle side
forces, I went with inexpensive, moderate torque servos.   I figure I could
always uprate the servoes as all the interfaces (mech / elec) are
interchangable.   If you order from servo city, you can specify the servo
to have 180 degree movement rather than the usual 90 degrees and then set
the endstops electronically via the resistor values on the rotary
switches.

http://www.servocity.com/html/hs-430bh_servo.html

David




On Fri, Nov 16, 2012 at 6:26 AM, <gow2 at rc-tech.net> wrote:

> Dave,
>
> I really like the machining you did for the bearings and such. What size
> are your servos?
>
> What circuits are you using to drive your servos?
>
> I did this first with the MGB years ago. The heater valve and the flapper
> in the heater box was cable driven. I changed the heater valve to the
> Vintage Air servo heater valve and then built a 555 circuit to drive the
> flapper:
>
> http://www.rc-tech.net/MGB/assembly2/heatd.jpg
>
> With the Pantera I am using an Arduino. I am certainly no circuit guru
> (more of a hack) but you don't have to be to use the Arduino. Basic hookup
> and basic program skills you can do amazing things with the Arduino.
>
> I even put out a book on using the Arduino to control a kiln (for powder
> coating). It can also be used for heat treating, or to drive an Exhaust
> Gas Temperature Circuit:
>
> http://www.lulu.com/spotlight/ArduinoKiln
>
> The book was written for someone with limited knowledge who has very
> little experience with the Arduino or programing. Somehow I suspect you
> have a background in this sort of stuff.
>
> When I set my eater box up, I changed the way some things are done. There
> seems to be an industry standard in heater controls and I wanted a bit
> more control.
>
> For starters, my defrost is a separate knob regardless of my vent position.
>
> My fresh air/ recirc knob is separate (which is normal). It is also
> variable. It starts out all fresh and as you rotate the knob changes the
> mix till it is all re-circ.
>
> My foot/dash vent is the same way. Starts out all dash vent, as it is
> turned the floor opens till half way, then the second half closes the
> vent.
>
> Any mix is simple programing.
>
> The testing is done with the Arduino "Uno":
>
> http://www.arduino.cc/en/Main/arduinoBoardUno
>
> When I want to make something permanent I use the Nano. I have a general
> 2-sided circuit boards made. It allows me to hook up servos, slots for
> thermocouple and 5v voltage regulator. This is a first generation board.
> The one's I have now have a heavier power run for the servos:
>
> http://www.rc-tech.net/cars2/arduino/nano.jpg
>
> This is another application I am using it for. I have a keyboard for
> input, lcd for display. Reads an encoder. Working on getting it to control
> the DC motor but having a hard time finding the right 90v DC motor board
> that will work with 5v control:
>
> http://www.rc-tech.net/cars2/arduino/brake.jpg
>
>
>
> Gary
>
>
>
>
> > Gary
> >
> > That has to be the prettiest heater box on the planet. :-)
> >
> > David
> > On Nov 15, 2012 3:01 PM, <gow2 at rc-tech.net> wrote:
> >
> >> Very cool. I built a heater box from scratch to do the same thing. I
> >> dropped the A/C. The weight savings, compressor, condenser, lines was
> >> over
> >> 100lbs:
> >>
> >> http://www.rc-tech.net/cars2/panttransam/HB.jpg
> >>
> >>
> >> Heater input Servo water valve in the front coming from a divider:
> >>
> >> http://www.rc-tech.net/cars2/panttransam/HB2.jpg
> >> http://www.rc-tech.net/cars2/panttransam/cooling/Tubes.jpg
> >>
> >> Gary
> >>
> >>
> >>
> >> > I've finally finished my project of converting the heater box and
> >> heater
> >> > valve to servo control and while it wont win any beauty contests I am
> >> > pretty happy the (functional) results.
> >> >
> >> > This allowed me to accomplish my goal of being able to match all the
> >> knobs
> >> > on the console,remove the cable controls on th heater, and get a
> >> heater
> >> > valve that shuts completely off.
> >> >
> >> > There's a few pics on POCA starting here:
> >> >
> >> > http://www.poca.com/index.php/gallery/?g2_itemId=38491
> >> >
> >> > And if you're really hard up for entertainment, there are two short
> >> > video's
> >> > explaining the operation here:
> >> >
> >> >
> >>
> https://picasaweb.google.com/110522871342119553583/PanteraHeaterServo?authuser=0&feat=directlink
> >> >
> >> >
> >> > With working heat and A/C behind me I decided to take her up into the
> >> > twisties in the back hills here in San Jose.   I had a great drive
> >> through
> >> > some very windy roads and came back with a big grin, some sore
> >> shoulders
> >> > and a few more projects:
> >> >
> >> > - Have to do something about bump steer
> >> > - Need to find the missing 200hp
> >> > - Need to tweak out some understeer.
> >> >
> >> > Comments welcome :-)
> >> >
> >> > David
> >> > _______________________________________________
> >> >
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