Brew computer Mk 2

[mitch]

Dallas 1 wire digital temperature sensors (which is a total lie as they need 3 wires)

If you power them parasitically you only use two lines.

[adm]

Dallas 1 wire digital temperature sensors (which is a total lie as they need 3 wires)

If you power them parasitically you only use two lines.

It's still not "1" wire though...... not that I really mind.....just bringing the marketing department to book.

Nonetheless....they are cool pieces of kit. And these guys:

http://www.earthshineelectronics.com/18 ... probe.html

have waterproof versions for £3.60 (although they are currently out of stock as I bought them all)....but I think in real life, they'd be best used in a thermowell.

[mitch]

It's still not "1" wire though

GND dosn't count . Remember that's two lines for the entire network of sensors, not two lines per sensor.

these guys have waterproof versions

The good thing about the normal (TO-92) ones is that they can make good thermal contact with the outside of vessels.

[Naich]

It's still not "1" wire though...... not that I really mind.....just bringing the marketing department to book.

You could use a copper stake in the ground at each end. Then it's only 1 wire

[adm]

It's still not "1" wire though

GND dosn't count . Remember that's two lines for the entire network of sensors, not two lines per sensor.

these guys have waterproof versions

The good thing about the normal (TO-92) ones is that they can make good thermal contact with the outside of vessels.

I think I'm still gonna stick 'em in thermowells though.....and as i don't really want to go through the walls of my vessels (ideally I want to be able to stir everything and whirlpool without banging into thermowells, and I don't trust the outside of a vessel as being particularly indicative of the internal temperature)[/color], I'll probably make them into long "dippable" wand type thingies. That way I can have them whereve in the mash/HLT I want.

Anyway....I'm not really bitching about the number of wires.....

Just this afternoon, I've managed to get a couple of the uncased versions up and running on the same single wire (+GND)...so it's all looking good.

To be honest, I'm having a lot of fun just playing around with the Arduino. I've just managed to get it playing "Smoke on the Water" via a piezo buzzer, so maybe the final brewery might sing to me as well...

[JamesE]

Sounds like you're making quick progress with the arduino, not sure how long mine would survive with the lass if I started knocking out guitar anthems on a piezo buzzer though

pump 50 litres from vessel A to vessel B

Given this requirement I would have thought a direct mass/volume measurement would have been easier (e.g. using scales/pressure/electrical capacitance etc.). A flow measurment would mean integrating the flow over time to compute the total volume. Errors in the measurment would accumulate over time which may or may not be acceptable for you. I know that RS has a range of reasonable flow meters some of which a designed for vending machines: http://tinyurl.com/2upooda

Not sure if these would meet you're requirements

[adm]

Interesting reading - thanks. I don't know enough about my requirements to figure out if they'd meet them yet

Right now I haven't really got as far as working out how best to do volumes and flows - still working on temperature....gas control and ignition comes next. The Brewtroller forum has some good threads on volume sensing which I'm still reading through.

Here's my breadboard circuit so far (this post is a dupe of another one about the brewery build from here on in.....) :



Arduino board, DS1307 real time clock, LCD display ( I need a bigger one) and DS18B20 digital temp sensor (only 1 wired, but the circuit supports multiple on the same1 wire bus )... the sensor had been immersed in my glass of scotch and soda (with lots of ice) and had read -0.44C at the lowest point, but was warming up again when the pic was taken.

All good so far - I can do the basics, which is read the temperatures on the sensors, log the temp and time and display it on the LCD. Next step is to actually get this lot driving solenoids and spark igniters (just bought two 4 port spark igniters from eBay for $24) and then to finesse those by using some PID code.....

It's all fun - if not the easiest way of doing things.

[howard]

Looking good - I would recommend a nice 4x20 display from China.

Be careful with the DS1820 with 2 wires, the specs indicates the parasitic powering stops working at high temperatures, I always run the +5v as well.

Big fatal fault in my system, I was away on business, got a 5 gal. batch in the fermentation fridge just before I left. Got home and found an un-fermented barrel of off tasting beer. We had had a power cut just after I left and the controller reset, so no heat. Being a cold May temperature dropped too low for Yeast to get going - rewriting the code now so it resets into brew fridge mode - some lessons are learnt the hard way

[boingy]

Big fatal fault in my system, I was away on business, got a 5 gal. batch in the fermentation fridge just before I left. Got home and found an un-fermented barrel of off tasting beer. We had had a power cut just after I left and the controller reset, so no heat. Being a cold May temperature dropped too low for Yeast to get going - rewriting the code now so it resets into brew fridge mode - some lessons are learnt the hard way

I dunno if that board has any NV storage but if it does you might want to look at adding some recovery code that will detect a reset after a power cut or brownout and retrieve its working parameters and operational mode (fermenting/heating/idle/whatever) from the NV store. This kind of stuff is standard on the military spec radios I used to code for (actually, they needed two copies of everything in case they were halfway through modifying the NV when the power went...)

One caution: if you do implement something like this, make sure you don't wear out the NV with too many unnecessary writes!

[howard]

Thanks - yes it does, and it's a good solution - I think we get a few 1000 writes, which will outlive my liver if I only need 1 write per brew.

[stringy]

What are the advantages to using the dallas 1-wire temp sensors?
My arduino starter kit came with an LM35, any reason why I'd not want to use that??

[asd]

As far as I know the DS18B20 one wire sensors each have an unique address, so they can be polled via the eponymous "one wire" bus, and thus many can be controlled via one processor.

I've bought an Arduino, and four of these DS18B20 http://www.ebay.co.uk/itm/180844405917? ... 2629wt_979, for £2.99 each, but haven't done anything with them yet.

Simon.

[JabbA]

No need to shell out for the DS18B20s, Maxim will send you free samples!!

Cheers,
Jamie