Temperature Monitoring

[Greenbeast]

My first thought is to have a more detailed picture of the tank temp, i obviously have the top and bottom sensors on the TDC3 but would like 5 readings ideally

I already have a slug although that is doing duty as its original intended purpose

i was looking for an extremely low powered device that would sit in the airing cupboard showing me 5-6 temp readings

[desperate]

Thanks for the links chaps, much obliged.
Have had a read through some of it and some of it makes sense, but it looks a little more complex than I really want, I think?? Like GB all I want is some thermometers that I can read remotely, no computer, no data logging , just a number display, I dont know if that is even possible, so I am sorry for being dense............think Osmium

Thanks again

Desperate

[Alan]

Meter £17.83 Got loads here, only one never worked from new.

Extra sensors £2.19

Maybe a five position rotary switch

Accuracy 0 to 400 Deg C is 1% + 3

Resolution 1 Deg C

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Test-Equipment/Multimeters/328-Digital-LCD-multimeter/31051/kw/test+meter

Regards

Alan

[wyleu]

Apologies, last night was a little hectic. I will try to get something together for the weekend.

[ericw]

As no-one has come up with a ready built system that measures and displays (except the meter) it looks as though you may need to consider building you own 1 wire master with in built display.

I would suggest an Arduino with plug-in LCD shield (2 lines of 16 chars) which would need very little in the way of hardware tweaking and, depending on how pretty you want it, could display up to 8 temperatures simultaneously.

However it would need to be programmed but there are libraries and examples available in the Arduino playground for the functions needed - scan 1 wire bus, convert to temperature and drive the LCD - so it would be largely a copy and paste job.

Relating the displayed results to specific sensors is rather more tedious, especially if you want to add/change sensors later without reprogramming. The obvious KISS solution to this would be a set of sticky labels around the display.

[Greenbeast]

Yes i started looking at arduino last night, so that can act as the 'computer' that interfaces with the 1 wire network?

I see they even sell a nice little LCD from the nokia 3310 that can be used, that way i could have my temps list vertically with a label next to them.
admittedly without further research i don't know how much more complicated it would be.

[JamesGreen]

There are several options if you wish the DIY route and wish to use BASIC.
PICAXE and PIC to name but two.
PICAXE editor is free and has a specific command for the DS sensor.
RF is pretty easy.
PCBs for LCD and GLCD also available with PICAXE.
(Note, I have no links to Rev-Education the makers of PICAXE. I'm simply pointing out an option)

[Greenbeast]

ah we use picaxe at my school, perhaps i should talk to the DT department

[desperate]

Nah,see you lost me when you got to picaxe, you say picaxe and I think pointy ended mattock, I'm sorry chaps none of the jargon means a thing to me

Alan, maybe that meter and sensors kit is for me, thanks.

Desperate

[dhaslam]

The metre looks like a good option with multiple sensors.

I have two of these wireless systems with two extra sensor/transmitters.    They are handy because they can be moved around but expensive and only read up to 70C.   
www.aquariumguys.com/pinpoint.html

I am going to try the one wire system  shortly.    One reservation I have  is the reliability , specially when used as a controller,  or has this been improved in  more recent equipment?     

[ericw]

For a really cheap solution try a whole bank of this type of thing

 http://cgi.ebay.co.uk/Digital-LCD-Thermometer-for-Refrigerator-Freezer_W0QQitemZ320433266103QQcmdZViewItemQQptZUK_Gadgets?hash=item4a9b4f9db7

If you were short of display space, you could cut off the sensors from all but one and connect via a switch to the remaining display. As I expect they use themistors (large resistance change with temperature) you would be able to extend the sensor cables without too many problems.
Stupid as it seems I bet the replacement batteries would cost you more than the whole item.

[Greenbeast]

i actually have one of those, bought for testing my chest fridge project was getting to temp.

It has a quirk that i can't decide whether it is a design feature or cheapo product flaw, you have to press the battery cover hard to get the display up.
I'm going with flaw although it does mean i can't be draining the battery too much

I think the 1-wire/arduino with lcd is going to be the best bet for me, i can mount it in the airing cupboard next to the TDC3 and it will give a constant temp display for 5 sensors on the cylinder. so we can estimate how much hot water we have for showering/clothes washing

[wookey]

I am going to try the one wire system  shortly.    One reservation I have  is the reliability , specially when used as a controller,  or has this been improved in  more recent equipment?     

my 1-wire system (doing control as well as logging) has been entirely reliable for the last year. I had one of my 5 tank sensors stop working - that's all. And I have cooked my panel sensors to stagnation a couple of times too with no ill effects.

I see no problems with 1-wire reliability, even when used for control purposes.

[langstroth2]

ditto, also for just over 12 months, all sensors still working. One sensor outside so has been down to -6C, one cooked once on a stagnating panel, the others have had to stand 365 daily changes of 20C - 60C - 20C (upto 80 in the summer). The only fault has been the wireless card on the data logger laptop that occasionally needs a stop/restart to get it to work again.

[Greenbeast]

Well i've bought an arduino and lcd display for it, now for the tinkering!
I've already got some lm35 temp sensors to play with, but i might stray into 1wire after i've familiarised myself with the hardware

Desp - if i come up with something before you've found your own solution, we can sort you out.