Raspberry Pi Control Box

[BrunDog]

Hi guys,

I realize that a commercial solution will draw ire when proposed in a freeware thread. I respect that and avoid providing advice on such threads when someone asks for potential solutions. I sincerely appreciate @augiedoggy's endorsement, and I'll affirm that he is not formally affiliated with BruControl. He is a user who I think has had a good experience - hopefully because we provided technical support for his build and help ensure his success.

That said, since you called him out for an inappropriate recommendation @golfindia, I will do likewise and state your continual highlight of a plastic toolbox as an acceptable enclosure for a high voltage/current control system is misguided. Many homebrewers stray from electrical codes or industrial standards due to funds, knowledge, and time, and that is understandable. However, actively demonstrating a dangerous design (flimsy, hole in top, fire hazard, etc.) which others may look to emulate may put them in harm's way should they follow your path as an experienced builder. Homebrewing is awesome that people are always willing to share and help out - but we need to be mindful of the risks that someone could get hurt with unsafe advice.

 

[jangevaa]

Sorry your thread has gotten derailed a bit @beer2d2, we should move on. How is the build/planning going?

 

[hethacker]

View attachment 705998View attachment 705997View attachment 705999View attachment 706000

I built something similar. The element rocker switches control the 3.3V DC signal from the RPI (which I have custom NodeJS web server with PID running on the Raspberry Pi).

I don't have any fuses, but it is attached to a GFCI 60A breaker. Maybe I should add fuses. I ran the 120V line to the contactor through both the key switch and the main power switch on the front power - but I think hindsight that it's overkill.

Mistakes:

• Original SSRs would NOT TURN OFF after they got hot! Very scary on the kettle getting a boil-over. I eventually found ones that I haven't had any trouble. Amazon.com I recommend a pull-down resistor ~10K for each 3.3V DC signal from the RPi.
• I put the 30A 240V plugs too close together. The large diameter plug on the cord interfered and I had to re-drill the hole location.
• OneWire temperature sensors (DS18B20) needed a real-time clock, so I had to make custom ATTiny85 microcontrollers with I2C communicating back to the RPi (calculate pull-up resistors as the ATTiny85 has too-high resistance build-in pull-up resistor).
• Attaching btween 1-3 OneWire temp sensors required lower pull-up resistor or I got erroneous readings. I think I settled around 2K instead of 4.7K. I don't recommend using OneWire temperature sensors for the only benefit that you can plug any temp sensor into any RJ45 connector.
• I connected a 7ft 6/3 power cord to my box. Very annoying to move the box around with a 10lb cord attached. I recommend putting a 240V 50A plug on the box itself.

Suggestions:

• Use 3.5mm Audio cables/connectors for the temperature sensors at both ends - I try to walk off with a hot/heavy mashtun and only to realize it's still attached (RJ45s do not pull out!)
• I use 5500 watt ULWD elements. For a 14 gallon batch a 50-60% duty on 240V will keep a rolling boil indoors. I hard-coded a separate boil power setting when kettle temp is over 205°F to prevent boil-overs. Defaults to 50% and does not use PID over 205°F, but is configurable via my web interface touchscreen.
• Get a screw terminal hat for the RPi - super convenient!

Notes:

• I used a dual port USB power for the dual fans (one in, one out) and the RPi. The 1/4" female spade crimp connectors fit over the 120V prongs very nicely.
• As mentioned in previous comments, the SSRs need the two terminals shorted (as in with elements) because they bleed a small amount of voltage and will dimly light your signal lamp when the power cords are not connected to the elements. I don't mind it as it's super dim and not confusing with "ON". Also tells me that the 30A 240V cords are not plugged into the kettles.

-Joel

That looks amazing! I love that RPi touchscreen, what is the software that you are using for it?

 

[craigmw]

View attachment 705998View attachment 705997View attachment 705999View attachment 706000

I built something similar. The element rocker switches control the 3.3V DC signal from the RPI (which I have custom NodeJS web server with PID running on the Raspberry Pi).

I don't have any fuses, but it is attached to a GFCI 60A breaker. Maybe I should add fuses. I ran the 120V line to the contactor through both the key switch and the main power switch on the front power - but I think hindsight that it's overkill.

Mistakes:

• Original SSRs would NOT TURN OFF after they got hot! Very scary on the kettle getting a boil-over. I eventually found ones that I haven't had any trouble. Amazon.com I recommend a pull-down resistor ~10K for each 3.3V DC signal from the RPi.
• I put the 30A 240V plugs too close together. The large diameter plug on the cord interfered and I had to re-drill the hole location.
• OneWire temperature sensors (DS18B20) needed a real-time clock, so I had to make custom ATTiny85 microcontrollers with I2C communicating back to the RPi (calculate pull-up resistors as the ATTiny85 has too-high resistance build-in pull-up resistor).
• Attaching btween 1-3 OneWire temp sensors required lower pull-up resistor or I got erroneous readings. I think I settled around 2K instead of 4.7K. I don't recommend using OneWire temperature sensors for the only benefit that you can plug any temp sensor into any RJ45 connector.
• I connected a 7ft 6/3 power cord to my box. Very annoying to move the box around with a 10lb cord attached. I recommend putting a 240V 50A plug on the box itself.

Suggestions:

• Use 3.5mm Audio cables/connectors for the temperature sensors at both ends - I try to walk off with a hot/heavy mashtun and only to realize it's still attached (RJ45s do not pull out!)
• I use 5500 watt ULWD elements. For a 14 gallon batch a 50-60% duty on 240V will keep a rolling boil indoors. I hard-coded a separate boil power setting when kettle temp is over 205°F to prevent boil-overs. Defaults to 50% and does not use PID over 205°F, but is configurable via my web interface touchscreen.
• Get a screw terminal hat for the RPi - super convenient!

Notes:

• I used a dual port USB power for the dual fans (one in, one out) and the RPi. The 1/4" female spade crimp connectors fit over the 120V prongs very nicely.
• As mentioned in previous comments, the SSRs need the two terminals shorted (as in with elements) because they bleed a small amount of voltage and will dimly light your signal lamp when the power cords are not connected to the elements. I don't mind it as it's super dim and not confusing with "ON". Also tells me that the 30A 240V cords are not plugged into the kettles.

-Joel

I like this implementation because it incorporates design features of industrial control panels with a GUI front end. I built my 1V/240 volt panel around a DSPR320, but at some point would like to upgrade it to RPi control. In my case, I'll probably adapt my CellarWarden software to allow for control of the brewing process. It also uses a Node.js-based server that links to a javascript front end, so it could be presented on a touchscreen on the front of the panel (or controlled remotely via any browser). I just need to find some time

 

[beer2d2]

Some things never change. You know when I made my last post with my recommendation based on what I use I figured you would chime in again with your incorrect assumptions that I have some affiliation with Brucontrol. Why is it ok for you to make recommendations based on what you have experience with but when I do the same you accuse me of advertising? I mentioned it because he might not be aware it exists or how it works and it always helps to be aware of your options before starting down any path. arduino setups are very similiar to the raspberry pi setups so its worth mentioning, especially when the OP just learned that CBPi is a discontinued piece of software. I have no motivations here other than sharing my experiences with the different setups Ive built and used.

I appreciate the alternative points of view, and feel that all commentary is beneficial. i also dislike when people get their panties in a twist and start calling people out. if it isn't what they are looking for they just need to hold their tongues.

 

[beer2d2]

Sorry your thread has gotten derailed a bit @beer2d2, we should move on. How is the build/planning going?

currently finalizing construction of the brew space, and will then start putting the kettles, pumps, steam hood in place, and will then concentrate on the electronics. ill post pictures soon

 

[beer2d2]

After studying your latest drawing update a bit more, it looks great! Adding the relay after the SSR is a great improvement. If you have auxiliary 120V available, such as a power strip on your brew bench, I wouldn't even bother adding it to your box. Then you could even get away with 6/2 wire since the neutral isn't necessary for anything. USB "wall warts" will take 240V just fine. FWIW, I have my two pumps mounted under my bench to a dual light switch box instead of taking room up in my control box.

-Joel

so I realized the power cord I am using is not 4 wire, its three wire L5 plug(stupid oversight). To your point then, I am going to have to take the 120v accessory circuit out of the box. I do have 120 on the wall already, so i can plug the pump into that. The problem i see now is that my relays require a neutral to switch the 120v coil. Should i pull the wire from the circuit panel and replace with a 4 wire L14 plug? or should i rework my control box to include 240v switched relays?

 

[RabbitHole]

Just to touch on one thing of your wiring. If I see it right your pumps are both pulling power off of the same buss bar in your panel... its almost not even worth mentioning in this small scale but its best practice to balance your loads across both sides of your incoming 220 both going back to neutral but both pulling from a different leg of power!

hmm, that does pose a situation now doesn't it.. what is the current Raspberry PI solution for brew controller then?

like above said. best to keep this to the point. but i would hate to see you go doen the CBPI road and then have to rewire. dont waste your time. its a dea project and the community is drifting!!

This is such an issue in my eyes. i was a CBPI user for three years. and just made the switch to BrewBlox With Brewpi.com... The community is amazing an issues that you have or find with the software will be fixed and updated within a few weeks sometimes even hours if it is a bad enough bug, but that's so rare...

Brewblox is lightyears ahead of everything that is out there in my eyes for the average homebrewer. Just the ability to automatically control the temp of your grain bed by itself, by using a pid to drive another pid in eiter your herms,rims, or kettle in BIAB... and the ability to automatically balance two elements on one 30amp circuit!!! I run both my kettle and rims tube at the exact same time and it balances the load and never fires either at the same time, just switches fast maintaining what ever % of duty that it needs to do its job that you are asking of it!!!

 

[doug293cz]

Just to touch on one thing of your wiring. If I see it right your pumps are both pulling power off of the same buss bar in your panel... its almost not even worth mentioning in this small scale but its best practice to balance your loads across both sides of your incoming 220 both going back to neutral but both pulling from a different leg of power!
...

There are some reasons in small panels where it makes sense to run both pumps from the same hot leg:

• You can protect the wiring for two pumps with a single 10A fuse, and use 16AWG wire for the pump circuits
• If you use an ammeter to measure the total current draw in your panel (not just the element), this becomes way more complex if you don't power all the 120V loads from the same hot leg

Brew on