I should probably throw in the towel. I have no business posting on a forum while lacking the most fundamental knowledge. It's not fair to you guys. Bryan Reagan, a stand up comedian, does a bit where he's taking very simple instructions from UPS on how to get some packages ready. After half of the first sentence, he says "Slow down!" That's me! So maybe I'll end the thread after today.
The problem in trying to help someone like me is that suggestions (do this), leads to "I don't know how to do that or what you're even talking about". While another beginner may see hysteresis as an obvious fix, I'm trying to figure out how to execute it.
Anyhow, I'm going to respond to the latest crop of generous suggestions. Any of you who see this as a lost cause can bail.
Answer to thermistor question:
75.8F = 10.72K ohms
60.1F = 14.76K ohms
Thermal control is currently off the table though as Arduino ADC output numbers are chaotic when power supply running.
Arduino is Uno Rev 3
(In addition to scrapping the original power supplies, I ditched the break out board the controlled them. That's where the Arduino comes in.)
As to my code: It's constantly changing with trial and error. The thinking was-- hit on something that works, and then figure why. I've had this wine cooler in the middle of our home office for (probably) four months. Remember, it's about the challenge, not whether the cooler is worth having in the first place.
The ideal completed project would have two Peltier elements on slightly different schedules: one for the lower half for white wine, the other for the top half for red wine (or the other way around). Additionally, there are two heat sink fans that would come on shortly after the Peltiers come on and need cooling. They might be programmed to stay on for a bit shortly after the Peltiers go off. Two more fans, one for the top half, one for the bottom half, are located in the cabinet to pull air over the cold sinks and into the cooler. Ideally, they too, would be on slightly different schedules.
As if that weren't complicated enough, There are controls on the door display to change the settings. That would be another project altogether.
What I'm shooting for now is an initial cool-down from room temp, maybe 30 minutes, and then an concessional restart of the cooler as the temp begins to rise. So, maybe, run both Peltiers and all fans (as if they were one) for 30 minutes. That seems adequate to get around 58F or so. Then, shut down for maybe 20 minutes. It seems insulated well enough to maintain a temp no greater than 62F or so. After the 20 minutes shut down, everything comes back on for ten minutes.
So, on for 30minutes; off for 20 minutes; then repeated cycles of off for 20 minutes; on for 10. Hopefully, that crude arrangement would have the cooler functional. I could go back to simple projects no bigger than the top of my work bench. In time I would master skills needed to improve the wine cooler, even the door, with proper code. Having said all that, I'm unable to go beyond mostly psuedo code as follows:
<code>
unsigned long top_fans_and_pelt = 8;//pin 8 turns on relay for top peltier and all fans
unsigned long bot_pelt = 9;//pin 9 turns on relay for 2nd peltier
unsigned long previous = 0;
int interval30 = 1800000;//30 minutes
int interval20 = 1200000;//20 minutes
int interval10 = 600000;//10 minutes
void setup(){
pinMode(8,OUTPUT);
pinMode(9,OUTPUT);
}
void loop(){
current = millis();//start the clock
if(current > 0 || < 5){
digitalWrite(8,HIGH);
digitalWrite(9,HIGH);
}
after 30", shut down (one time)
then off 20"
then back on 10"
repeat over and over
}//end loop
</code>