Usb Thermometer & Controllers?

[Tim F]

Hey all,

I have written a PID controller in visual basic and now I'm looking for a way to read temperature and operate an element accordingly via USB. Does anyone know of a USB thermometer that would let me read live temp values? And same for a controller - I don't know what I'm looking for there but need some way to turn an element on and off. Any advice? I thought I'd see if using my lappy for the controller was cheaper than buying a standalone controller and it lets me log temps easily too which is nice.

Cheers!

 

[mh971]

Hey all,

I have written a PID controller in visual basic and now I'm looking for a way to read temperature and operate an element accordingly via USB. Does anyone know of a USB thermometer that would let me read live temp values? And same for a controller - I don't know what I'm looking for there but need some way to turn an element on and off. Any advice? I thought I'd see if using my lappy for the controller was cheaper than buying a standalone controller and it lets me log temps easily too which is nice.

Cheers!

something like this could do the control, but is not much help with temp input

http://cgi.ebay.com.au/Geovision-GV-I-O-US...=item20b558c110

 

[mh971]

something like this could do the control, but is not much help with temp input

http://cgi.ebay.com.au/Geovision-GV-I-O-US...=item20b558c110

http://www.temperaturealert.com/Temperatur...FQlspAodPHAvgQ#

and the temp input but you'd need usb ext lead

 

[outbackbob]

Hey,

I'm building up a brew controller now using an arduino as the brains, Dallas Ds1820 temp sensors and some 240v solid state relays for switching elements on and off.

All parts available on eBay and pretty cheap too!

Let me know if you want more info.

My brewing hobby has taken a back seat while I play with electronics for now

Cheers.

 

[Yob]

not sure if this helps but I use one of these

 

[Tim F]

Cheers all! Will read through all those links.

 

[mh971]

not sure if this helps but I use one of these

Me too, pretty hard to beat for price quality and ability in my opinion.

I think Tim is talking about automation of brew day rather than ferment though - not sure.

 

[Tim F]

Yeah I have a similar fridgemate and it is easily my fave bit of brewing equipment. But this is for intelligently controlling a heat exchanger for the mash tun if I ever get around to making one

 

[rich_lamb]

Yeah, it's pretty easy to write software for a PC but then you find the problem is connectivity! USB isn't that useful - you're stuck hoping somebody has implemented a solution to your problem (but they make pretty much everything for USB don't they!), and when you do find it if it's any good it costs a fortune.

The cheapest and most flexible way to do this is with an embedded controller; like a lot of guys have done with little arduino boards or whatever. Have a look at sparkfun for a good range of options.
Incidentally - sparkfun have a few little USB enviromnent monitors for reading temperature on a USB port. But you'd prolly find it's not much more to by a fully featured controller and use it for the heater as well.

You can still control an embedded board from your PC; just using it as a dumb switching thing, but you'll probably figure its better to put your PID control in the gadget and free up the laptop for reading AHB...
(there are also USB based I/O boxes, like the Labjack, which you could get for less than a couple of hundred $ - still more exxy than a full embedded controller, but no software to write).

The next big problem is switching mains from whatever controller you use. Somebody's probably selling some sort of USB controlled switch - though I've never seen them. Most guys with a controller will just use solid-state relays as they are very simple, and if you spend at least a couple of bucks on them they are fairly reliable. I use Triacs myself, as they're cheaper and smaller, but I need to build PCB's for those. Whatever option you use - be careful. It's not worth dying to control brewhouse temperature, so treat mains voltage with respect.

hope thats of some use...

 

[dmerrick]

I'veused some of the gear from phidgets, lots of diffent i/o options and they provide the SDK. Just had a quick look and they have thermocouple inputs but no RTD inputs. www.phidgets.com

 

[Tim F]

you'd prolly find it's not much more to by a fully featured controller and use it for the heater as well

After checking out some of the links it's looking that way - Seems like I can get a standalone controller and an SSR from ebay for under $50. But cheers again for all the advice.