1 Posted: Saturday, October 31, 2015 8:44 AM

I was reading up on the STC 1000+ hack of the STC and wondered if I could manage to perform this task.

The more I read about it, the benefits of fermentation temperature profiles outweighed the “this looks difficult” factor.

Then I decided that the 2 probe version would be good to build. The 1st probe monitors the temperature of the wort. The 2nd probe monitors the temperature of the fridge. You can set a temperature where the fridge/heater cuts out if the fridge's ambient temperature becomes too cold/warm compared to the current wort temperature.

This is designed to prevent temperature overshoots. So if you have the fridge set to 12 for a lager, as the wort temperature approaches 12 the fridge ambient temperature will drop colder. Once the wort hits 12 the fridge cuts out, but the cold air of the fridge continues to cool the wort…. a little more. This modification is to try to prevent any overshoot. Most people do not see detrimental overshoots and this mod is more “something nice” rather than “something critical”.

The benefit I see, is if fermenting at the lower temperature ranges of a yeast you are not going to accidentally cool the yeast out of suspension.

I ordered the correct version of the STC 1000 from the correct seller on Aliexpress and a Arduino clone from Fleabay along with the miscellaneous items. Not everything arrived yet but I have flashed the unit with the new firmware with fermentation profiles preloaded. And I desoldered and removed a screw terminal.

I am waiting for the new screw terminals, chip resistors and spare temperature probes to arrive to complete the job.












More reading here if you are interested.
https://github.com/matsstaff/stc1000p

https://github.com/matsstaff/stc1000p/blob/master/usermanual/README.md

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2 Posted: Saturday, October 31, 2015 9:38 AM

Looks like a good project. Most things like this are on the fence in terms of value proposition, but I reckon if it related to something you enjoy (brewing) and you learn stuff in the process then it tips the scales every time towards being worth it.

Interested to hear more as it progresses.

3 Posted: Saturday, October 31, 2015 10:47 AM

The aliexpress store had them back in stock? Thanks!

4 Posted: Saturday, October 31, 2015 12:44 PM

zargonb:

Looks like a good project. Most things like this are on the fence in terms of value proposition, but I reckon if it related to something you enjoy (brewing) and you learn stuff in the process then it tips the scales every time towards being worth it.

Interested to hear more as it progresses.


Given the actual cost to flash the new firmware is $7.10 for an Arduino Uno compatible board and some wires $2.30, 5 pin header was $1.57 for 10; the extra functionality of temperature profiles is well worth the cost. I could have done it cheaper if I bought the Arduino Nano.

The benefit of 2 probes is probably debatable, but the 3 pole screw terminal was $3.19 for 10, the extra temperature probes $5.85 for 5, the chip resistors were $3.65 for 200 and $2.59 for tweezers. And I have left overs. I'll probably make up 1 more 2 probe unit. However, I'll report back on how it works out.

I have decided to mount an Arduino Nano compatible board inside the final project box ($3.75) and a diode to protect it while connected to mains ($4.45 for 10). This way I can update firmware if updates become available. Or if I want to change fermentation profiles it will be quicker to re-flash the firmware with the profiles set to begin with rather than push a bunch of buttons to set the temperature set points and durations.

And as you say the learning about something connected to brewing is rewarding.

I'm also currently planning an Urn based 1 vessel system for all grain and am likely to use the OVBSC version so the gear will get repeated uses.

5 Posted: Saturday, October 31, 2015 9:01 PM

Bit beyond my skill but I did see someone hooked up a port purely for flashing. May be an option instead of mounting the aduino in the case as well.

6 Posted: Sunday, November 01, 2015 11:06 AM

Quadricorn:

Bit beyond my skill but I did see someone hooked up a port purely for flashing. May be an option instead of mounting the aduino in the case as well.


That was my original plan.

But I figured I could do this for a couple of bucks and only have to plug in my STC 1000 black box into the computer.

Either are good solutions. I don't fancy having to take the STC unit out of its case if flashing is required.

7 Posted: Tuesday, November 03, 2015 8:05 PM

Looks like they sent me the wrong chip resistors. They sent 10 ohm instead of 10K Ohm. I kept getting wrong readings on the 2nd probe. I thought it was my soldering so kept trying and ruined the soldering point. I got frustrated and broke out the mutimeter to check the resistance…. that's when I found out.

These things are as small as fleas and a PITA to work with. I'll try again to try for the neater result next time and I'll verify the resistance 1st.

So in the wash up I have to use the alternative, less neat and tidy, but easier way.

Update soon.

8 Posted: Tuesday, November 03, 2015 11:08 PM

Make sure you do keep us up to date

9 Posted: Friday, November 06, 2015 10:33 PM

I have success.

The STC 1000+ is now two probe.

I soldered in the 10K ohm normal resistor in the programming header then replaced the wires. I soldered in a wire which I will use to connect the plug jack to on my project box. Then I have temporarily soldered on the temperature probe.

I re-flashed the unit to make sure the connections are secure. All good.

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10 Posted: Monday, December 14, 2015 3:52 PM

I used the picture on this page to work out wiring for a red blue common cathode LED.
https://github.com/matsstaff/stc1000-datalogger/blob/master/README.md

This is to show when a signal is being sent to each relay.
The LED lights up red when heating and blue when cooling.

I got the LED from eBay, they arrived today. I soldered a 100 ohm resistor to the leg for blue, 150 ohm resistor for the leg for red and a wire on the common -ve leg. The red led leg was wired to terminal 9 on the STC 1000 display header, blue was wired to terminal 10 and the common leg was grounded on the last terminal.

I threw the probes in the fridge. And it works!

Now I have to work out attachments to show the evidence.

11 Posted: Monday, December 14, 2015 8:21 PM

Fired up photo bucket to do pics.






12 Posted: Monday, December 14, 2015 8:50 PM

Nice work! I was going to go down this road but in the end I purchased a down and dirty digital thermometer from my local Jaycar store, for under $20.00.

After confirming that my STC-1000 and my newly purchased unit were as near as dammit in agreement with each other I immersed the sensor of the Jaycar unit into my FV (filled with water to negate the risk of contaminating a brew) and used the STC-1000 to read the temperature of the air in the fridge. I then manually ran the fridge by hand-operating the switch to the mains AC supply, turning the fridge off when the FV liquid was “on temperature”.

It didn't take long to work out what the hysteresis was and I was able to prevent overruns by switching off the fridge when the air temp was 0.3C below the required wort temp and then adjusting my delay for the restart of the fridge.

Obviously this will vary from fridge to fridge, FV to FV etc, but I was able to work out the settings for my most frequently used fermenting temps and now have a little table of settings stuck to the door of the fridge. Now it's just a simple matter of setting the STC-1000 to match the brew I'm making. All up it took me around an hour to suss it all out.

I was an electronics tech in a former life and, frankly, I'm well and truly over the “tinkering” stage. But that doesn't stop me from admiring people who have a crack. Well done.

Cheers

13 Posted: Monday, December 14, 2015 9:18 PM

Be aware that DIY electrical work is not legal. Any issues arising will not be covered by house insurance - eg an electrical fire and a house burning down.

14 Posted: Monday, December 14, 2015 10:32 PM

Ben 10:

Be aware that DIY electrical work is not legal. Any issues arising will not be covered by house insurance - eg an electrical fire and a house burning down.


It's not electrical work. It's an appliance.

15 Posted: Tuesday, December 15, 2015 2:03 PM

…waste of time mentioning it Ben….I got abused quite substantially on another site for mentioning such things back when STC1000 was a new product! I was concerned by some of the questions people asked in regards to how things should be wired. I am a sparkie but when I mentioned the legalities I was severely chastised!…..

16 Posted: Tuesday, December 15, 2015 5:42 PM

rossm:

…waste of time mentioning it Ben….I got abused quite substantially on another site for mentioning such things back when STC1000 was a new product! I was concerned by some of the questions people asked in regards to how things should be wired. I am a sparkie but when I mentioned the legalities I was severely chastised!…..


I'm not being flippant with electricity and I got the 240V side checked out when I wired up the my 1st one.

These hacks are all on the low voltage side and are not going to cause a fire.

I'd be more concerned about STC 1000's being wired up in systema style lunch boxes than a properly wired unit in a project box, which has been modified to temperature ramp, use 2 probes and light up red and blue when the signal is being sent to the relays.

And it is still an appliance not hard wired electrical work in a building.

17 Posted: Wednesday, December 16, 2015 10:45 AM

…not doubting your work or your attitude Matt, in fact the pics indicate that you are pretty competent, it is worth noting though, we are in an age where common sense has been replaced by duty of care and various liabilities!

18 Posted: Friday, December 18, 2015 5:29 PM

I got 2 more flashable A400_P versions of the STC 1000 today.


It is very possible to solder in the flea sized SMD resistors and get a 3 pole terminal soldered in.


Here is the temp of probe 1.


Here is the temp for probe 2.


A much cleaner way to do it.

19 Posted: Saturday, December 19, 2015 9:42 AM

I got the LED attached to this new unit and wired up the Arduino Nano. I used a couple of zip ties for tension relief on the wires. I also put a Bat85 Schottky diode on the 5V wire.

A little tidy up with some heat shrink and it will be ready to go in the box.

20 Posted: Thursday, January 07, 2016 11:40 PM

I got it all in a case finally. Here are some pics.

I graunched the case a bit cutting holes. Oops.