RockfordWhite
Well-Known Member
- Joined
- Dec 3, 2007
- Messages
- 473
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- 11
Due to the awesomeness of the system I will have to let your naming conventions slide.... THIS TIME
I used trial and error to determine a pulse width that would keep a rolling boil. Using temperature as a gauge really doesn't work well, since the temperature of a violent boil is nearly identical to the temperature of a simmer. I found that throttling back to about 50% kept the boil rolling really well.Did you determine your pulse width experimentally or did you use a feedback loop with a variable setpoint? I'm wondering if setting the boil to 212, 213, or some other temp would be optimal for a good steady boil without overdriving the element.
Using temperature as a gauge really doesn't work well, since the temperature of a violent boil is nearly identical to the temperature of a simmer.
That's exactly what I was thinking. Perhaps a PID algorithm isn't really needed at all. Simply 100% duty cycle until 212 (adjusted for altitude) and then go to 50%. I wouldn't think it would need allowance for a small amount of overshoot.
By the way, awesome brew hut! I'll be building in the basement but I don't think I'll be hitting your standard. I haven't finished rebuilding the entire inside of my house yet.![]()
You know, I'm really regretting not putting a temp sensor in the boil kettle. In fact, I nearly wrote the code to do exactly what you suggested, Fingers, until I remembered that "tempKettle" didn't exist! I think I'll probably add another thermocouple soon.
I think 'sugar water' will boil a little higher, at least in the little I've done.
That sounds like a fine approach. I would use the following conditions: temp greater than 200° AND stable over a long enough period of time to assure that the temperature rise is complete. That way there's no chance that you'll throttle the element back at a low temp. I have not specifically measured and charted the rise time, but I think you can be reasonably assured that the temperature will stabilize +/- one degree once a boil is achieved.I am going to try the changing temperature approach, when the BK temp is the same for 3 cycles 30 seconds apart then boil is true. I was wondering if you have had the time to monitor BK temp to see if temperature rise stops at boil.
Looking forward to "free day." Thanks for the mention because I was about to forget!
I'm using the 168 in the brew hut. The standard Arduino has 6 analog inputs and 15 digital input/output pins. If you use multiplexers or one-wire/serial devices, your options become greatly increased. If you really need more pins, use an Arduino Mega (or Sanguino), which has roughly double the number of analog and digital pins.
Here is the enclosure that I built to house the Ping))) sensor. I calibrated it today. It appears accurate to at least +/- one quart. I can live with that for now.
It is to measure volume in either the mash tun or the kettle (will work with both). With the right sensors and setup, measuring mass could take the place of measuring distance as a means to determine volume.