This is a side project to build a wifi furnace temperature controller with ramp-soak function that will use a wifi website to set temperatures and display current temp readings. It had a delay of a few months before I realized the MAX31855K Ebay temperature sensor boards that I bought were all fakes and it wasn't poor programming on my part. Anyway I'm using well under $20 of parts: an ESP8266/ESP12F wifi module and the MAX31855K: cold junction compensated, K type thermocouple input, 14 bit SPI digital output IC. I'm not using the SPI interface but bit banging three IO pins which should allow a touch LCD screen to be used if desired. For the most part I'll have it accessed with a tablet or smartphone.
A bit more progress on a rainy afternoon: I can now use the unit's wifi to serve up a web page with changing temperature data. Making this web page interactive with ESP8266 is going to be fun!.
My car is French so anything electronic has to be stupidly over complicated and very unreliable!!! I think it was W3 that did it to control his burner many years back, he had quite an operation going making the cast CNC kits.
Those ESP8266's have a single channel of analogue to digital which could read a Lambda sensor. You could pulse width modulate a car fuel injector with a spare IO pin, although maybe a motor driven needle valve would be more useful. On a slightly related fuel mixture note: She looked deep into my eyes and said, with a husky voice "Talk dirty to me!!", so I leaned over close and whispered in her ear "Volkswagen diesel!".
Nope Jason, one of these.. It was cheap and features an 'adaptive automatic gearbox' quite wtf it adapts to I have no idea! Perhaps I should feed it red wine and brie every time it goes into limp mode. W3 used a perustal..prysta... per.... one of those metering pumps to regulate the oil to the burner and also the air from the blower and had quite a succesful set-up from what I remember, he was buying his petrobond by the tonne until the business side of vaping caught his eye and he shut it all down. Edit: That looks even more fugly in the marketing photo than it does in the flesh!
So after a steep learning curve I have a barely working WiFi connected temperature controller. This unit connects to my home router and dynamically updates the temperatures in realtime instead of constantly reloading the website. It's using a small 28 volt bulb as the heater and keeping it set to 32 degrees C with a MOSFET switch. Now I have to implement a decent interface to set the temperature and hysteresis settings and also metric/imperial units of measure. It'll eventually function as a password protected wifi website and switch a solid state relay. I'm pretty stoked so far! Heater element is the orange glowing lightbulb up the top with a thermocouple cable tied to it. The temp reading updates twice a second right now:
The creativity around here never ceases to amaze me. I'd love to sit my lazy duff on the couch and monitor my kiln. Instead I have to toss a security camera in front of the pid and watch the feed on my phone.
I'll have to put it online so people can make them once it's running well, I don't think there are very many similar projects out there. Not sure I want the liability of selling prebuilt units after someone uses it to warm a humidicrib or similar.
