New project!!!!!!

Starting a new project soon and need a bit of input. I would like to monitor the temps in 4 different vessels and have an alarm sound and flash the 7 segment display to indicate a temp is out of the set range. I would also like to run a 115 VAC pump on a demand on/off switch, a water line control to manage a n immersion chiller and a Reverse Osmosis Boost pump too. Ideally I would like to interlock the power off of the panel till the air legs have fully extended. Once fully extended I would like for the start-up procedure to require a setting in each monitored temp area. The Piezo buzzer should beep 1 to 4 times and repeat to indicate which vessel is out of range either too high or too low temps indicated by red, green, and blue led segments near each 7 seg temp readout. I understand the DS18B20's can all communicate on single wire on one pin only on the processor. Once I get all the input from the single wire units can I then use different outputs to control what I do with each reading? I would also like to add an RTC to do countdown and alarm functions for a one hour boil time. The DS18B20's run on 5 volts, the 40X2 runs on 5, the air solenoid switches run on 100 VAC, the Boost pump came with a transformer to step it down from 115 VAC to 24VDC. The air interlock solenoids will also need an indicator LED to signal when to use the second stage of the extenders. I could only find 6.75 inch travel cylinders for a reasonable price so I just bought enough to do each leg in two stages. I also ordered several 40 Amp SSRs with 3-32VDC input signal sides and up to 240 VAC on the output sides. I have a HUGE box full of photocouplers and small parts like caps, resistors, cables, connectors and LED's, pots and basic components. This device is for home brewing beer so I need accuracy and durability as well as water resistance and humidity rejection at higher than ambient Florida temps/humidity. I would love to discuss the basics and finer points of this system before I start building boards and soldering so I can make sure I have everything covered and properly addressed. Thanks in advance for your thoughts and inputs. It's a major newcomers project but I have plenty of time so I can hopefully get it right the first time.

"Wheelchair Bob"


Senior Member
Wow, that is a project,

everything is completely do-able and sounds like you have all the right parts. Personal preference says that since you are using a 40 pin micro, the need to use the one wire network may not be needed. It would be much easier (for a beginner) to use "readtemp" on the 4 different lines. I would also (and do) use the SSR's you have mentioned as they are very reasonably priced (in the USA anyway) for the wide range of applications they can be used for. But my best piece of advice is break it down into multiple sections and get each piece of the puzzle working the way you want then add the pieces to the whole one at a time rather than trying to write everything at once.

Good luck and keep us upto date!!!! :)


Technical Support
Staff member
As buntay says, quite a project, and best approached in parts.

I'd start with getting the temperature monitoring working using READTEMP or READTEMP12 with Programming Editor Terminal display first, then adding the temperature display and status indicators. Then you can use OWIN and OWOUT commands to improve the speed of temperature reading if you want that.

You can run your temperature monitoring in parallel with what you already have and then it's just incremental development turning what you have into a fully PICAXE controlled production system. There is nothing I can see that isn't doable.


Senior Member
This device is for home brewing beer
Sounds quite an interesting project, and as already said it's perfectly doable, just work on one aspect at a time.

However, I can't visualise the whole thing. Why has a brewing setup got telescopic legs ?
The original space to store the brewer was very limited and the foot print of the machine was deemed(by me during mock up phase) to be unsafe due to high temp water at heights above my shoulders. So rather than rebuild as a larger device I simply added a set of telescoping legs to allow the footprint to go from 7.5 to 17.0 square feet. When the device is not in use I can retract the legs and allow it to be stored in a minimal amount of precious space in my "man cave/Mad scientists work shop", but when in use I can extend the legs fully and not be very concerned about tipping or sloshing in an unstable design. This way I get the best of both worlds and I remain safe from a possibly serious burn while in my wheelchair. The Reverse Osmosis system and the March pump system are just because I wanted to explore water chemistry and flow characteristics. The rest of the temp monitoring is because brewing has several very critical temps that must be reached or maintained for the end result to be consistent and repeatable. So I was thinking since I have a spare 40 pin chip, why not explore some system integration and electronics in the over all equation too. Unfortunately this is what happens when a fertile mind (full of shot) and a project collide. The project explodes into a study of whats possible, just because you can. This at least is what has happened to the original simple three tier brew stand I started out to build. It is now comparable to "Brew Complex 39A" at Kennedy space center in Florida. At least it sort of looks like a launch pad anyway. Have fun and enjoy, I will post pics soon as the build progresses.

"Bobber in a hobber"

Ummmmm, Houston....we have a problem.....Were out of beer!!!!
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