Who is interested in Custom Temp. Controllers?

[Garak]

I'm putting together an order in the next few days for parts and I'd like to get an idea of how many people are interested.

Each one will be custom built for the application. They can be used for heating, cooling, or both. Most of the sensor options can handle 0-100 degrees Celsius. Outside of that range is going to take a little different approach but is doable. I'm ordering both mechanical relays(for compressors) and solid state relays(SSR, for heating elements). USB control is optional, I'm also looking at a few LCD options. Currently its just a thermostat but I'm working on developing full PID functionality. I'm also working on a brew timer.

I build this stuff as a hobby so throw some curve balls my way. I love a good challenge.

My cost in parts is around $20 for the basic cooling version. Maybe $30 for controlling 20A+ heating element.

I would to build these for trade but I would accept cash if it came down to it. Things I'm looking for: Stainless steel kegs of all types and sizes, grolsch bottles, a CO2 tank, CO2 regulator, small deep freezes, a friend with truck, machining and/or welding, hot wort pumps, vacuum pump, solenoid/motorized valves, ~30' 8/4 SOOW or similar cable, weather proof electrical boxes, 30-50A GFCI breaker, etc... Most of these items are worth way more than one temp controller.

I should also say. I'm not a professional engineer or electrician. How you use these controllers is up to you. I cannot be held responsible for any damages or injuries. Don't assume that any of this is safe.

[akr71]

I'm interested in a heating element. I'd like to know a little more, though. Is it intended for regulating mash temp or could I use it to boil? If boiling is doable, care to hazard a guess on how much wort it could bring up to a boil? I'd be happy enough using it for step mashes and decoctions, though if I can brew indoors in winter that would be sweet!

I have a pile of Grolsh & Fischer bottles which I won't need once my kegerator is finished.

[jason.loxton]

Garak:

Curious to know what it would cost to get this up and running again? http://halifax.kijiji.ca/c-buy-and-sell ... Z260378519

I just cracked my coolant line and lost my refrigerant, and am rather desperate (need beer!!!!) for a new mini fridge. I have been trolling the interwebs and there's nothing available right now. If I could get this one cheap, it could be a solution.

[John G]

As long as the compressor runs, it will work. I have a similar model to that fridge, and have the thermostat set to maximum and have the power to the compressor controlled by a temperature controller with a temp sensor inside the fridge. If the thermostat is stuck on, a controller will be fine, or you can bypass the thermostat altogether and just use the temp controller.

[chalmers]

I'd be interested in a couple, maybe more? Something for a brew belt/fermentation chamber, and working towards a fully electronically-controlled gas-free system (HERMES, etc).

[Garak]

akr71:
The controller can be programmed for to do both HLT and boil pot at the same time. How much you can boil depends on how big of an heating element you use. For my build I'm using 4700watt elements which should easily bring 7.5 gallons to a boil. In an insulated keggle you would likely be able to boil even more.

For HLT applications your going to want the USB option or LCD option so you can change the temperature settings for each step in the process.

The controller could also control a RIMS setup, control pumps, etc...

jason.loxton:
As John G says the the temperature controls I make can replace the thermostat. My parts cost is around $20 to do that.

Here is a mock up of what the controller boards might look like. I haven't firmly decided if I'm going to use this type of protoboard(the brown part).

2011-02-20 11.22.36_Halifax_Nova Scotia_CA.jpg

This is the functioning prototype and other circuits I've been toying with. This is what I test the firmware on.

2011-02-20 11.17.07.jpg

[ratchet]

you could always make some printed and etched copper boards if you didn't want to use the protoboard.

[Garak]

If there is enough interest I may design an PCB and get it manufactured in china for like $2 a board. Etching boards at home is more trouble than its worth.

[maltster]

I'd be interested in a controller for an electric HLT, MLT and maybe boil kettle. I just started building a new boil kettle using a 55l keg and a 4500w element. Can one controller be used for more than one process? I looked at PID controllers but they seem pricey. I'd like a temp display or maybe just the USB option as it would be easy to connect to a netbook.

[akr71]

akr71:
The controller can be programmed for to do both HLT and boil pot at the same time. How much you can boil depends on how big of an heating element you use. For my build I'm using 4700watt elements which should easily bring 7.5 gallons to a boil. In an insulated keggle you would likely be able to boil even more.

For HLT applications your going to want the USB option or LCD option so you can change the temperature settings for each step in the process.

The controller could also control a RIMS setup, control pumps, etc...

Sounds good to me, I still would like one. The cooling thermostat sounds interesting too, but I have one already and only one freezer (so far).

Will it be 120V or 220V? It doesn't really matter since I'd use it in the laundry room.

[Garak]

One controller can have up to 6 analog inputs(temperature sensors) and 6 or more timer outputs. The possibilities are endless. More IO can be added as needed.

For 220v stuff the expensive bits are the mechanical relays and solid state relays(SSR) that are used to switch high current. The electronics that I'm developing are the cheap parts. Don't forget the cost of cable, breakers, connectors, enclosure, etc... that stuff adds up really quick. I'm ordering 25A SSR's from china for about $7 each and they need a $5 heat sink. That is good to control a 220v heating element up to 6000 watts but its best not to run them at max current so anything under 5000 watts should be ok. All electronics and wiring should be encased in grounded metal and/or you should use a GFCI breaker to power everything. For a 4700watt element you would want at least a 30A breaker and with a 30A breaker everything should be wired with #10 or bigger wire. 30A+ GFCI breakers start at like $130. I'm searching for a cheaper source.

For 110v lower current stuff like heat belts and small fridge compressors the extra cost are minimal. You don't need much more than my controller board, a relay and a wall wort power supply(old cell phone charger?).

[ratchet]

If there is enough interest I may design an PCB and get it manufactured in china for like $2 a board. Etching boards at home is more trouble than its worth.

it's not all that bad... we made quite a few boards using the laser-printer and iron method.

[Garak]

Ratchet:
Its just that is so easy to get professional manufactured boards made these days.

Alot of work goes into etching boards, then drilling them and then you end up with an ugly PCB. Getting double sided boards to line up properly is a PITA. The holes are not plated. etc...

A batch of 10 5cmx5cm double sided boards cost $20, 10x10cm is $40. At that price you can't even buy the supplies to etch at home.

http://www.seeedstudio.com/depot/fusion ... ?cPath=185

I've ordered parts from these guys before. Free shipping on orders over $50. Takes no more than a week to arrive. This will be the first time I used the PCB service.

[ratchet]

fair enough.

We were using single-sided, with 28ga jumpers on the back

[Jmac00]

how much for a controller to run a keezer? either price, or grolsch bottles for trade, pending how many you're looking for. but i'd have to find a way to get them to you.

[Jayme]

I might be interested in a partial controller... I'm an Electronics Tech myself and happen to have access to a pretty sweet "junk room" (aka heaven!) at work where I can usually get all the wire, relays, fuses, etc. But if you're willing to work out some sort of deal, I'd be in! I've been meaning to make a few controllers but haven't had the time.

[mr x]

I love these mad electronics skills we are bringing onboard here. Nice work!

[maltster]

I'd like to get a controller with 2 temp sensor inputs and 2 x 25A SSR outputs with the option to add more I/O later on. I probably have suitable heatsinks here. (lots of cpu heatsinks w/fans) How large a heatsink is needed? My load is a 4500w element, approx 18A @ 240v. How much would the temp display cost? And how much for the USB option?
Is possible to modify the code/firmware later on? I'm a retired electronics tech myself. Is special development software requirement?

[Garak]

malster:
The heat dissipation from SSR is something like 36watts at 18 amps, based on an estimated 2volt drop across the SSR. Not a lot to dissipate, you might be able to get away with just using an aluminum enclosure as a heat sink. I'm just going to use the ones that are designed for the SSR to attach to, its just nice neat and clean looking.

I just found a serial LCD display for less than $15, which is about the same cost as the USB to serial board. Its one or the other, as there is only one serial port(UART) on the atmega168. It is possible to bit bang out a second serial port if you really wanted both USB and an LCD.

I'm writing all the code in c and using the free AVR-GCC compiler and avr-libc libraries. You will need an in circuit programmer(ISP) which sparkfun sells for like $15. Its just a USB to SPI interface with an additional IO line(Reset) to put the atmega into programming mode. I'll give my source code to whom ever wants it. I may even release it under the GPL at some point.

Jmac00:
Around $20. Do you want to replace the freezers thermostat or just have a box that the freezer plugs into?

[Jmac00]

Jmac00:
Around $20. Do you want to replace the freezers thermostat or just have a box that the freezer plugs into?

box that the freezer plugs into....similar to a johnson controller i guess.

[Garak]

I ordered the parts today. I have enough parts coming to build 10 temperature controllers rated for 10A 120v. I also have 6 25A SSR coming for high current 220V heating elements. I'll build the relay controllers for controlling keezers, kegerators and heat belts first. I should have a few ready within a week of the parts showing up. Those parts are coming from dipmicro.ca in Canada so it shouldn't take long for them to show up.

The parts cost for the relay controllers is around $20 each. I'm recycling old computer power supplies for the case. I can also build it inside of a plastic electrical box if you want something nice and small. They sell for around $10. Ideally you supply the case, I have a few computer PSU cases kicking around if your ok with them.

2011-02-23 16.40.21.jpg

2011-02-23 16.40.02.jpg

For the heat belt controllers I can easily add more sensor inputs and relay outputs. For about $10 a set. The controller has analog 6 inputs for temperature sensors and lots extra outputs.

I've decided not to design a PCB at this point. Maybe down the road. I've found a proto board that is pretty close to what I would make, it just has a few extra holes. Its not the one pictured above, but similar and red.

[mr x]

How are these coming along? I am becoming interested in fermentation temperature controllers so I can free up my PID...

[Garak]

Still waiting on parts. They only shipped on Friday. Paypal now uses some sort of eCheque that takes like a week to clear before they advise the seller to ship. Its shipped Ontario, so it should only take a few days to get here.

--
Chris

[Garak]

The parts arrived yesterday. The relays have an odd foot print that won't fit on the boards. Its not a big deal, its just not going to look a neat and tidy as I would like. The relays will have to be glued to the bottom of the case.

I've figured out that I have enough IO pins on the micro-controllers to run a cheap LCD with two temperature probes and two relay/SSR outputs. The LCD displays are $5 each with two lines of 16 characters and a blue back light. They can run in 4 bit which only uses 7 IO lines. Now I just need to write the software to drive the LCD.

[gyorke]

Assuming the LCD is a hd44780 compatible I have source code I would be happy to share. Just send me a PM and I will email it to you.