Arduino Development Thread

[angus_grant]

I received my USB data acquisition device and have hooked up my DS18B20 temp and am reading temps from it. It is very easy as the temperature code has been built into the device. So I just tell the digital pin it is in temp mode and read back some ASCII text from the digital pin which gives me the temp. I have 7 other digital or analogue pins (I tell the pin which mode it is in) to control through simple serial port commands (which are so easy to do in C#). So I'll be able to control my 25A SSRs for heating element and pump.

I am planning on my C# app parsing BeerSmith or BeerMate recipe files and build up the schedule straight from the file instead of entering all the info again.

I'll hook up the Netduino to a flow controller I have and set up a display on my keg fridge to read how many litres of beer have been poured. Thus letting me know how little beer is left in the keg. At least I'll get some warning that the beer I am pouring will be my last from the keg. :'(

 

[Edak]

..
I'll hook up the Netduino to a flow controller I have and set up a display on my keg fridge to read how many litres of beer have been poured. Thus letting me know how little beer is left in the keg. At least I'll get some warning that the beer I am pouring will be my last from the keg. :'(

LOVE that idea!

 

[vortex]

Is it possible to wire up an STC1000 temp probe into an arduino, and then output that temp to the STC1000 so it continues to control the temps? I'd like to hook up the arduino to the fermenter probe to graph it's temperatures, but don't want to have multiple temp probes around the place if I don't have to...

I don't exactly understand how the temp probe works, so I don't know if this would actually work or not.

 

[Edak]

Is it possible to wire up an STC1000 temp probe into an arduino, and then output that temp to the STC1000 so it continues to control the temps? I'd like to hook up the arduino to the fermenter probe to graph it's temperatures, but don't want to have multiple temp probes around the place if I don't have to...

I don't exactly understand how the temp probe works, so I don't know if this would actually work or not.

Not really. Instead I wold recommend that you have a different sensor for logging.

 

[mILLrAT]

Is it possible to wire up an STC1000 temp probe into an arduino, and then output that temp to the STC1000 so it continues to control the temps? I'd like to hook up the arduino to the fermenter probe to graph it's temperatures, but don't want to have multiple temp probes around the place if I don't have to...

I don't exactly understand how the temp probe works, so I don't know if this would actually work or not.

The STC probe is a thermistor, that is the resistance of the probe changes in proportion to the temperature (logarithmic relationship). You can measure a thermistor on the arduino using a voltage divider circuit and an analog input. You then need a calibration equation to turn the measured resistance into a temperature. It is a lot of mucking around. Also the arduino only uses a 8 bit analog to digital convertor and at one end of the temp scale (low end from memory) you might find the resolution is one degree celsius.

I use an arduino for temp control of the fermenter fridge. I use a DS1820 probe that I tape to the outside of the fermenter and 2 solid state relays, one for the heater, one for cooling. A LCD for display. I am currently playing with a SD card for data logging.

 

[bonj]

The STC probe is a thermistor, that is the resistance of the probe changes in proportion to the temperature (logarithmic relationship). You can measure a thermistor on the arduino using a voltage divider circuit and an analog input. You then need a calibration equation to turn the measured resistance into a temperature. It is a lot of mucking around. Also the arduino only uses a 8 bit analog to digital convertor and at one end of the temp scale (low end from memory) you might find the resolution is one degree celsius.

I use an arduino for temp control of the fermenter fridge. I use a DS1820 probe that I tape to the outside of the fermenter and 2 solid state relays, one for the heater, one for cooling. A LCD for display. I am currently playing with a SD card for data logging.

I was not aware that the STC probe is a thermistor. That is interesting information.

I do however, have to correct you on the ADC on the arduino, as it is in fact a 10 bit unit.

 

[Edak]

I was not aware that the STC probe is a thermistor. That is interesting information.

I do however, have to correct you on the ADC on the arduino, as it is in fact a 10 bit unit.

Either way, it is a LOT of fuffing around and even if you can get the arduino to measure the thermistor. Do you know what the input impedances are of both measurement circuits? The suggestion of using a voltage divider will almost definitely stuff up the measurement of the non-arduino temperature controller. In other words it greatly depends on how the other device works...

The typical method for measuring these is to use a known current source, which is a great method for using voltage dividers.

It's ohms law (V=IR). If you change the resistance then you will change the current flow or the voltage. If you set the voltage and change the resistance then the current will change, but how is an arduino going to measure a change in current? By running it across another series of resistors. This is called a wheatstone bridge.

You will need a wheatstone bridge to measure fine differences in resistance, this is the ONLY method for strain gauges and other small resistance changes. This is not really basic stuff because you will then need to have balanced resistors and reference voltages, etc and as I said earlier it also depends on the measurement circuit of the other controller.

When there is a constant current source (which is how the devices I work with every day) then changing the resistance directly translates to a change in the voltage across the resistor, which is EASILY measured with a standard ADC.

My 2c is not to bother with it, use a DS18B20.

Speaking of which, I just received my awesome temp probe from sure electronics, the one with the DS18B20 in a stainless thermowell. NIIIICE!

 

[bonj]

I totally agree on the DS18B20. They're good little units and simple to use. I have some stainless thermowells I got from http://www.brewershardware.com/ which are awesome.

 

[Edak]

I totally agree on the DS18B20. They're good little units and simple to use. I have some stainless thermowells I got from http://www.brewershardware.com/ which are awesome.

Yes but these DS18B20 sensors had the perfect thermowell already attached.
Cool sensor

edit:I like the link you provided, cheap fittings!

 

[bonj]

Yes but these DS18B20 sensors had the perfect thermowell already attached.
Cool sensor

edit:I like the link you provided, cheap fittings!

They those premade sensor ones you linked look awesome! Brewers Hardware does some premade ones, but not as cheap as the ones you linked from Sure Electronics. Nice find.

 

[angus_grant]

OUCH. Have a look at the shipping costs though. $US60 for shipping, and that was only for 3 cam fittings... :-O

 

[Edak]

OUCH. Have a look at the shipping costs though. $US60 for shipping, and that was only for 3 cam fittings... :-O

From where?

 

[angus_grant]

From where?

Brewers Hardware in the US.

 

[matho]

been thinking of adding a small proto area to the brauduino so it can bring out the spare pins and ppl can use them something like this



thoughts?

cheers steve

 

[MastersBrewery]

matho would that be for like add an input or output or i2c? (think its called i2c) :blink:

 

[matho]

wasn't the plan but I suppose you could, I was just thinking there are 4 spare pins and they could be used for other things like controlling another SSR or adding volume sensing via load cells.

I am thinking adding wireless comms of some sort so i can make up a "pager" type device for the brauduino so you don't have to stay in ear shot of it when brewing, but I'm still thinking about it and haven't designed anything yet.

cheers steve

 

[matho]

Ok after receiving the PCB's yesterday they look good so I have decided to post the EAGLE files that I used to create them. I don't want ownership of the Brauduino so here they are do with them as you please, maybe develop it further.

View attachment ahb_brauduino.zip

cheers steve

 

[dmac80]

wasn't the plan but I suppose you could, I was just thinking there are 4 spare pins and they could be used for other things like controlling another SSR or adding volume sensing via load cells.

I am thinking adding wireless comms of some sort so i can make up a "pager" type device for the brauduino so you don't have to stay in ear shot of it when brewing, but I'm still thinking about it and haven't designed anything yet.

cheers steve

I've been working on a similar setup with ethernet, i've modified your code to add a webpage that i can access though my home network. It will show number of steps selected, current step, current set temp, actual temp, and a few other things. It's still a work in progress and increases the program size somewhat, but it will be handy for me as i can do some parenting inside and know the status of the brew out in the shed.
I also added a start delay timer and pre heat routine to allow setup the night before and have water at mash in temp when i wake up.

Cheers Dan

 

[matho]

I've been working on a similar setup with ethernet, i've modified your code to add a webpage that i can access though my home network. It will show number of steps selected, current step, current set temp, actual temp, and a few other things. It's still a work in progress and increases the program size somewhat, but it will be handy for me as i can do some parenting inside and know the status of the brew out in the shed.
I also added a start delay timer and pre heat routine to allow setup the night before and have water at mash in temp when i wake up.

Cheers Dan

sounds awesome Dan can wait to see pics, I have a delay setup in the original braumiser but I have never used it so I left it out on the brauduino. Thats the beauty of the arduino very easy for people to change the code to suite them, when you have it up and running I would love to see some of the code

cheers steve

 

[dmac80]

sounds awesome Dan can wait to see pics, I have a delay setup in the original braumiser but I have never used it so I left it out on the brauduino. Thats the beauty of the arduino very easy for people to change the code to suite them, when you have it up and running I would love to see some of the code

cheers steve

Yeah Steve, programming the Arduino is fairly straight forward once you get your head around the syntax (for most simple functions). I haven't got any pics of the webpage at the moment (left the arduino at work), but it is very basic html text, no frills.

View attachment DodgyBrau.txt

It helps that your code was well written. I can guarantee that mine won't be though. I changed the button assignment also as i had bought a freetronics display (probably wouldn't buy another) with 5 buttons with dropping resistors that go into analog 0.

I've been looking at adding mash and boil programming to the ethernet interface, but the program was getting a bit large.

Got a cheap Arduino Mega off ebay with an ethernet shield so i might still do it.

Cheers