Stc-1000+

[Spellman]

I don't have an open one close by, but since the unit can be powered when hooked up to an arduino, there is a good chance that it would be 5v to keep everything simple inside. Doesn't mean that I'm right, just my guess without having one in front of me.

 

[OneGlobe]

This one delivered a 'good' STC-1000:
http://www.amazon.co.uk/gp/product/B00IJ0F2OW/?tag=skimlinks_replacement-20

FYI, I also got a "good" one from the source above!

This is a fantastic project!!! 1000+ thanks @alphaomega and all contributors!

/anders

 

[jleiii]

I don't have an open one close by, but since the unit can be powered when hooked up to an arduino, there is a good chance that it would be 5v to keep everything simple inside. Doesn't mean that I'm right, just my guess without having one in front of me.

That would be my guess as well. My recollection is that there is only 1 voltage regulator on the main board, but the relay would be perfectly happy with the unregulated power feeding the 5v regulator. So it could go either way.

 

[alphaomega]

That is correct. I believe that from the transformer, there is a rectifier and smoothing caps that puts out dirty 12v (ish). Then a regulator feeds 5v to the logic. Then there is a transistor for each relay to drive the coil with the 12v.
That makes sense, as the mcu can't drive the relays directly and using the regulated 5v would put extra load on the regulator and might affect logic power.

 

[Bigdaddyale]

http://www.ebay.com/itm/Pro-Mini-at...ible-CP2102-USB-2-0-to-UART-TTL-/200937465025

 

[alphaomega]

Alpha, thanks for the e-bay pointer on the pro-mini/CP2102 combo. I couldn't help but order a few extras since they are so cheap.

Regarding the last post from StoneBriar, I'm still running 1.04 on my "production" units and haven't had the chance to open the cases up and update them.

On mine, if I soft power-off the unit, unplug them, and then plug them back up to mains, I see some junk like StoneBriar mentioned appear on the display for less than a second before the display goes blank. At that point, soft powering on turns the unit on fine.

Did you change anything that might relate to that between 1.04 and 1.05? Sounds like 1.05 might be leaving the junk on the display until you soft power the unit on. Was that intentional?

Thinking back, I seem to recall you saying that implementing an "off" display for a few seconds after applying mains power would take up too much code space.

Yes, I changed completely how the soft off was handled between those versions. From handling the condition in software, to turning off the timer that handles the logic. The display should be initialized, but I might have to review the code and check the order that stuff is done during init. That would be the probable cause. I'll have a look at it when I can.

Are ppl really using soft off?
Here are my arguments against it:

• it does not turn the unit off, it only blanks display and don't run logic, you really need to turn off mains to power off
• it is confusing (even if I fix it so screen would blank correctly at start up)
• it uses more codespace than I like for such a shi*ty feature, codespace that could be put to better use, I only included in the first place because the original firmware has it
• the button could be put to better use

I'm not unreasonable. If this really is a feature that ppl want, then ok. But I would really like to get second thermistor input to do something useful and need to free up code space to do so. The button could be really useful as well to switch between which temperature is shown.

 

[wilconrad]

My $.02: get rid of "soft off" and free up the code space. The feature creates more confusion than value. If I don't want the unit to run I can unplug it or build in a switch to disconnect power.


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[disney7]

+1 ^^^

 

[ejluttmann]

I have a situation where I use "soft off". I have four controllers in a single box, three of them each control a single conical fermentor. It's a glycol cooled system, so for cooling they simply turn on/off the flow of glycol. For heat they will control some heat tape. The forth one controls the glycol chiller. They are all fed from the same power source and the "soft off" allows me to turn off the conicals not in use. I may be the odd duck here, but maybe you can make it a compile option in the project?





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[krazydave]

I use it.
In my setup, I use several chest freezers for fermenting and they aren't always in use. All of my mains outlets are behind the freezers, so the soft off is the easiest option to keep the freezers and heaters from coming on when they aren't needed.
Without it, I'd have to mess with unplugging power cords which messes up my tidy wiring that I struggle so hard to keep in place.

However, I could live without it, but I do prefer it to be there.
Then again though if you came up with some other amazing feature to use that button and code space for (which you are very good at btw!), I doubt I'd miss it too much.

 

[disney7]

Would it work (and not use any more code space) to just have it display "OFF" in the soft power off state? That way you'd know it wasn't controlling anything and it would remove the blank/gibberish display confusion.

If you didn't want it wearing out your led display, you could still unplug it or put a switch in.

 

[DrunkleJon]

I have a situation where I use "soft off". I have four controllers in a single box, three of them each control a single conical fermentor. It's a glycol cooled system, so for cooling they simply turn on/off the flow of glycol. For heat they will control some heat tape. The forth one controls the glycol chiller. They are all fed from the same power source and the "soft off" allows me to turn off the conicals not in use. I may be the odd duck here, but maybe you can make it a compile option in the project?

View attachment 216375
View attachment 216376


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Thats purdy. As a n option, individual rocker switches could be a solution if the soft off is removed.

 

[ejluttmann]

Yes displaying OFF works. I'd prob prefer that vs blank screen anyhow. Really just use the soft off functionality


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[ejluttmann]

Thats purdy. As a n option, individual rocker switches could be a solution if the soft off is removed.

Yes, i was originally going to add power switches but then realized I didn't need to


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[Spellman]

I'm another soft off guy. I have individual hard-wired switches for the functions, but not the units. I like the soft off simply because it will silence the alarm if no sensor is plugged in. In my experience they only display the gibberish if they loose main power and it comes back on when they are in soft off mode. Turning them on then soft off again clears the display and the world is right again. I really like this feature for fermentation, and I'm not sure there is really any more features that I could think of to add to justify removing the code, but then again I'm not the coder and don't know what is in the realm of possibilities. It may be something that could be removed for the mash versions where there might be more gain and they wouldn't be run all the time.

 

[alphaomega]

I have a situation where I use "soft off". I have four controllers in a single box, three of them each control a single conical fermentor. It's a glycol cooled system, so for cooling they simply turn on/off the flow of glycol. For heat they will control some heat tape. The forth one controls the glycol chiller. They are all fed from the same power source and the "soft off" allows me to turn off the conicals not in use. I may be the odd duck here, but maybe you can make it a compile option in the project?

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Holy freakin' moly...
That is insane. Props!

Displaying "off" won't help much. If anything it will add, a bit of code (to show "off"). The biggest part is actually the state machine to detect the key press and duration.
Even removing the soft off functionality won't save an awful lot of codespace. But I'm really tight on it so every word counts.
Ok, so I'll try and keep the functionality if possible, and if possible show "off".
I'm trying to refactor the code to see if I can free up some space, but I it pretty well written from the start

 

[alphaomega]

And thanks for posting the pictures by the way! Awesome to see your builds! And furthermore, it is nice to see that there are STC-1000+ units in use. I haven't had a lot of feedback, so I was under the impression no one really uses it

 

[Spellman]

I think it is quite the opposite, it works and there is nothing to complain about!

BTW the word "excess" is not in my vocabulary. I had been thinking about doing fermentation control, but your firmware is what kick-started my build. Right now I have a mini fridge with a coolant tank and individual pumps for the fermenters. It works ok, but later this fall when I get some time I'm going to do it up right with a glycol chiller made from a window ac unit. I have dupont cables soldered into the boards all with the same color wire, so all I have to do is pop the front off and hook the same colors up to the corresponding cables on my arduino. Here is a shot of the inside when it was about 90% done (note that the top unit measuring coolant temp isn't an actual stc-1000). Everything is very low amperage, so I don't worry too much about everything being on one circuit. Someday I hope to start a new thread with my build and things that I found that have worked and didn't work. Once again I went down this path because of what you did with the firmware, and that really sparked my imagination on what could be done. I have a commercial grade eherms system I built last December, and now I have a commercial grade fermentation control.

 

[ejluttmann]

Agreed ... It just works for me. I actually have two others that I have wired up individually to control a freezer fermentor and a "cold box".

Plus I've also programmed several for folks in the neighborhood as well.

There is the possibility that I might someday replace a few of them with a Arduino like setup if it would allow for remote monitoring - but everything I've seen so far are a project in itself and looks to be a maintenance nightmare ... But these work so well, cheap and so easy to use, I'm in no hurry - if ever.


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[bigvalen]

I likely missed it somewhere back...but what's the problem with the v1.1 units ? Not able to get the board into a flashable mode ?

(I bought two on Amazon, one turned out to be a WK7016C1, which seems to be a copy without cooling ability, the second is a v1.1, so I'm .. a little irritated).

 

[disney7]

I likely missed it somewhere back...but what's the problem with the v1.1 units ? Not able to get the board into a flashable mode ?

(I bought two on Amazon, one turned out to be a WK7016C1, which seems to be a copy without cooling ability, the second is a v1.1, so I'm .. a little irritated).

The other flavors of STC are a completely different processor, so Alpha's code won't work on them.

 

[alphaomega]

Hi guys!

I have pushed the initial changes for v1.06 to the work branch.

I have added support for a second temp probe. I have added 'OFF' display when in soft off mode and it should work even after power is cut

This version adds a couple of items to the 'Set' menu

• tc2 - temp correction for probe 2
• hy2 - hysteresis for probe 2
• Pb - Enable/disable probe 2 (disabled by default)

With probe 2 enabled, the control algorithm will also cut heating or cooling, when temp2 exceeds setpoint +- hysteresis2.
The idea is that it should measure ambient fridge temp (or a smaller thermal mass) and with a correctly set hystereris2, cut heating and/or cooling before beer reaches setpoint and limit under/overshoot. You will need to experiment with the setting to find what suits your system.

To connect an extra probe, you need (apart from the probe) a 10kOhm resistor (preferably 1% tolerance). All the connections needed are available on the programming header, so it is easiest to hook it up there.
From above the board, the connectors on the header (left to right, starting closest to the transformer) are:
ICSPCLK, ICSPDAT, GND, VCC, nMCLR

Connect the resistor between ICSPCLK and GND. Connect the probe between ICSPCLK and VCC.
You can have the probe attached and still program the STC, but if you (like me) want to power the stc's logic from the programming header and do testing, you must disconnect the ICSPCLK line after programming, as having it connected affects the temp reading otherwise.

If you do not have an extra temp sensor, you need a 10k NTC with beta 3435 (25-75 I think, but retailers seldom specify). I've been using these, cheap as dirt, but with wires that are very thin. But they work well. You might want to add a capacitor in parallel with the resistor (for noise suppression) 10-100nF should be the range. With the cap in place, programming wont work, so you might as well have a different header/connector for the the extra probe that you can remove when programming. The cap is not necessary, but would be good (I have not tried yet with a cap myself).

I've had to do a bunch of refactoring to be able to free up the codespace needed to pull this off (it is tight as <insert dirty joke here> now!!!!). And as always, I have only written the code, but not done much more, I need your help testing it! I hope/think the controller algorithm is ok, I think highest probability of bugs lies in handling EEPROM variables and menus. That reminds me, this version has slightly new EEPROM layout, so you'd do best in reinitializing EEPROM, but if you have profiles you want to keep, you can retain it but then you would need to check/set every item in the 'Set' menu.

*Phew*.... Long, post. I hope I got everything down.

In short, please, please. Help testing this version, both with and without the extra probe. Report any bugs. As I said it is tight now, but if there is anything you think should be tweaked or changed. Do tell. I really think this might be the final version, (that is there will be no more features only bug fixes, if they appear).

Thanks and cheers!
//mats

Edit: Dang it! I forgot one thing. With temp probe 2 enabled, you can switch between which temp is displayed by doing a short press on the power button. An additional LED will indicate that you are watching temp 2.

 

[ejluttmann]

Cool ... I'm thinking this 2nd temp probe could come in handy for my "cold box" ... It is chilled by using a modified air conditioner (temp control has been overridden allowing for colder temps) which works great but will sometimes freeze up at lower temperatures. When the coils freeze up it blocks the flow of air and it actually gets warmer in the box, this prevents the air conditioner from getting turned off and the coils never get a chance to 'thaw'.

I'm thinking I can solve my problem by using this second temp probe and placing it on the coils of the AC - this would shut off the the air conditioner if they get too cold and should prevent the coils from freezing up on me. This should allow me to actually run it at lower temps than I can now. At least might be worth a try

 

[Spellman]

That's a great idea, might have to pick up a 5th stc for when I build my chiller. Please let us know if it works as well as it does in theory!

 

[ejluttmann]

I just ordered a 10pack of those temp probes ... I'd actually like to see if they work better in my thermowells too ...

 

[stoneBriar]

Are ppl really using soft off?

I use it, but I'm not sure I'd miss it. The only time I do it is on brew day between fermenters moving in and out. I turn off the unit so that it won't cycle the fridge/heater on and off as I drastically change the temps and have the fridge door open a lot. I can just as easily unplug the unit in these situations.

 

[alphaomega]

Well, the soft off functionality stays. I managed to scrape together enough space by refactoring the code. And I think displaying 'OFF' was the correct move. Less confusing and it shows that the unit is powered, but not active.

Has anyone tried flashing 1.06? And has anyone had a chance to play with the mashing firmware?

 

[wilconrad]

Well, the soft off functionality stays. I managed to scrape together enough space by refactoring the code. And I think displaying 'OFF' was the correct move. Less confusing and it shows that the unit is powered, but not active.

Has anyone tried flashing 1.06? And has anyone had a chance to play with the mashing firmware?

I've flashed the mashing firmware and poked through the menus, still waiting for my RIMS tube to arrive from Brewers Hardware to give it a proper try.

Quick question, though: how does the constant output mode work and what am I adjusting with it? A pulse width?


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[alphaomega]

The way output works is that it takes the chosen timeperiod and divides it in 255 pieces. 0 is totally off, 255 constantly on, and 127 on for half the period and off the other half. Constant output lets you set it yourself, instead of the regulator updating it based on temp.
It can be useful, to set correct power level to maintain boil if you run eBIAB for example.

 

[wilconrad]

The way output works is that it takes the chosen timeperiod and divides it in 255 pieces. 0 is totally off, 255 constantly on, and 127 on for half the period and off the other half. Constant output lets you set it yourself, instead of the regulator updating it based on temp.
It can be useful, to set correct power level to maintain boil if you run eBIAB for example.

That's awesome, looking forward to testing it out!