Hi,
haha, yes it is a bit large I guess, by today's standards at least. 1985 Monte Carlo SS.
Yeah, F. the environment lets burn some dead dinos
(I really miss my old '72 Dodge/Holley/Edelbrock/Etc./Homebrew electronics constellation
)
My much smaller C230 has dual zone too, and it's nice when the lady wants to be toasty and I would like a more human temperature range
Sure, it must be hard to stay cool with a hot lady next to you
The worm gear/DC motor sounds like a much better idea. The servos having to stay energized had crossed my mind, but I am not familiar with most of this proposed hardware, so I wasn't sure if that was common practice.
Nah, it's an R/C servo special, you might say. I wonder why nobody makes a worm drive R/C servo, as battery life/weight is a really big issue in eg. glide planes.
You might wanna hang on to the cables used with the manual regulation, or, if it's solid wire, replace them with Bowden cable, as you can then place the motors, side by side, in a convenient place. That will make it easier to mount them and to work with them.
Ageed on the not needing any of this to work until after the car has fired. Would the micro controller not reset automatically when it sees enough voltage? What is a reset circuit?
Sometimes it
would reset - would you settle for sometimes?
A reset circuit can be very simple or more involved. It's purpose is to give a well defined reset pulse at a predetermined time or on this or that condition.
In your case, I'd make it reset when nominal voltage has been present for say 3..10s, or (if your SS has got an ECU) when the "motor running" signal from the ECU becomes active - the idiot lamp would be another useable indicator.
And what is the load dump, causing 60-80+ volts?? Wow, I have never heard of that. Very curious!
Load Dump is THE beast, but there are other baddies that needs to be dealt with as well.
Load Dump happens whenever you dump a load *doh* but comes in different flavors, the absolutely worst is when a more or less discharged battery gets disconnected while rev'ing the motor.
Your generator works hard to charge the battery, making lots of power and suddenly the load disappears - like if you have a kid hanging in your stretched arm and they let go, your arm goes up and so does the voltage, since the generator have a mass that cannot brake instantly, same as your arm.
According to SAE, a Load Dump can be up to 125V peak, but a more conservative number is 60..80V (it depends on generator speed, inertia and its inductance, the load change magnitude and how fast it happens) and the decay may take up to half a second.
Happened to me once, when a road service jump started my Dodge in a snow storm and took off before I disovered that they wiped out my entire charging system by removing the cables, as they opened one of my quick disconnect battery clamps in the process.
I started my trip home with dim lights and being extremely cold, I stopped thinking and turned on the heating fan, the battery gave up the ghost the very second (Luckily I had a thermo monkey-suit in the trunk, or I would have gotten really ill, as it was about 5 years before my first cell phone and I was miles from anywhere when it happened). Yeah, Load Dump stinks
Minor examples of load dump can be measured each time you turn off a load, like your head lamps, your fan, stop running power windows etc.
The exact opposite happens when you engage a load - The voltage dips some and then gets back up in a blink - if you're on a dark road, you should be able to see the effect of it, when you turn your fan, power antenna or similar on and off.
Then there's noise from the ignition, some of it through the supply (B+ line) and some by capacitive or inductive coupling into other leads. Relays turning on/off does their bit to amuse the environment and practically each change happening in a car will mean noise in the electrical system.
Newer cars will be better dampened due to the EMC directives, but you cannot make a car (electrical) noise free.
What kind of controller would you reccomend?
I use mostly PIC controllers myself, while most people here use AVR controllers.
Normally, I tell people to use whatever they're comfortable with, have tools for, understand etc. but since you haven't got any pref's (I assume) you could use whatever you like, as long as it have the specs needed.
When programming in C you'll notice little difference if any.
You should choose a controller with a temperature range of; automotive, industrial or extended of course and it should have enough A/D-converter inputs for your temp.gauges and enough digital I/O for whatever else you need. Hardware PWM is nice (not a deal breaker though).
Before I can be more specific or even give you type numbers, you need to specify exactly how many temp sensors you need, how many motors you need to control, whether they should be uni- or bidirectional, how you want it to control the windows (eg. button input) etc. all down to the least bit of what and what not.
So, sit yourself in a comfy chair, get the hot damsel to serve you a cold one and start doodling - when you're certain you have covered all eventualities, we can find a specific chip model.
More important than the exact flavor of chips, is the (protection of the) supply for it and driving the motors, so you need to find some numbers for them as well - voltage and max. current at the very least. this can be done at a later stage though, as this is for the "support circuitry" and not the controller itself.
