simple in theory

[papa_lazerous]

I'm looking for something that I am sure must be eaily available and easy to find with a bit of googling, but I've come up with nothing.

I want to have a temp probe in my system which diplays the temp on an LCD that I can mod into my case, I must be able to set it so that when the temp reaches an upper limit it switches a load like a fan and once the temp has gone down to the lower level it turns it off.

Pretty much the same idea as a thermostat....

So I am sure there must be controllers made for this I cant find anything.

I would settle for buying some kind of probe and LCD setup that worked to show temps and then make a simple device that switched at the required temps but I've got limited resources mainly Maplin Electronics which arent very helpful nowdays So any constructive help or ectronically minded people that are interested in showing me the right direction to go in will definately be helping me allot

[STEvil]

edit - n/m mercury switch wouldnt work.. ;)

[crodan85]

A microcontroller would be your best bet. I have seen a few projects using temp IC's with LCD's but It shouldn't be overly difficult to modify for you needs.

[papa_lazerous]

KNow who I need to talk to by any chance?

[crodan85]

Erm I can point you in the right direction but I don't think you will find ready made solution. I can think of 5 different ways to do it but as you said simple in theory not so simple in construction/programing.

Using a PIC LCD and DS1621/DS1631 Temp IC
http://www.geocities.com/jbfullen/Electronic/PRJ1/PRJ1.htm

[crodan85]

Here is another one
http://www.geocities.com/jbfullen/Electronic/PRJ2/PRJ2.htm

[IYP]

go to fCPU and look thru the fan controler section...then try to find it somewhere else...while they have one of the largest selections, they are pricey

[papa_lazerous]

go to fCPU and look thru the fan controler section...then try to find it somewhere else...while they have one of the largest selections, they are pricey

fCPU?? Care to share a link with me

[IYP]

http://frozencpu.com/

;)

[papa_lazerous]

I think the easiest way round this problem is to simpy but a temp probe that can display the temp via a display, which there are plenty available. And somehow get a thermostat that I can fit a probe to so it will monitor the temp of something specific rather than air and set it at a temp and keep the 2 systems seperate that way it may be easier for me to build something myself. without the need for too many IC's that I dont understand

[IYP]

http://www.frozencpu.com/bus-53.html?id=BQUi3Sro

http://www.frozencpu.com/bus-74.html?id=BQUi3Sro

all found here
http://www.frozencpu.com/scan/se=Fan%20Accessories/se=Fan%20Controlling%20Devices/mp=menu_search.html

[papa_lazerous]

I've looked at them all before making my last post, non of them are suitable becasue they are for controlling fans and monitor the RPM of the fans which they control, but i want to be able to switch a load at a set temp which would be either on-off but the fan controllers will just increase or reduce the voltage and will alarm out when they know there isnt a fan connected as they monitor RPM I want to be able to use the switched output to trigger a relay that turns on the PSU for my pletiers

Hmmm thinking about it I could make this simple. I culd power the pletier's via a relay where it is always off so the water would just circulate and have a probe that reacted at a temperature so that the resistance changed and then triggered the relay on so that i ad the cooling power of the pelts once the temp got lower the probe would no longer have the temp to hold the relay on and then it would continue like that, all I need to do is get some kind of probe or thermistor (am I right in thinking thats a resistor that reacts to temperature) and build a small circuit to make it react to a cirtain temp then I am in business I know ther are people here with this knolwedge

[eddieate]

get a DFI motherboard like the Ultra-D for example you can control up to 3 fans off it in the way you want and its a damn nice board anyways.
/Ed

[IYP]

are we controling fans or pelts here?

[papa_lazerous]

I am not controlling fans it may have been misleading to use that as an example in the original post. I was using it as an example.

It doesnt matter though what I am switching I just want a simple on/off once a temp has been satisfied. temp hot=switch on temp low=switch off. simple its just a thermostat with a probe on it. i dont even care about an LCD anymore I just want the simplest of things that must be out there

[eddieate]

ahh ok the motherboard won't be much help then, i'll give it a think tomorrow, its a bit late now :)
I know what you mean about maplins takes ages to get stuff for a project from there not all the stores seem to have everything in the catalouge so you pick everything out and go to get it and when you get there they don't have it and you have to rethink the whole thing in the shop, i always take a pen and paper now.
/Ed

[papa_lazerous]

My maplins used to have intelligent people that understood wht they where selling and the applications for them and could give advise, now its a toy shop with an electronics counter at the rear with some spotty faced till operator, no knoledge anywhere... :(

[papa_lazerous]

ok I thought about it and come up with this

http://www.screwfix.com/app/sfd/cat/pro.jsp;jsessionid=PZKPNXANDT3XYCSTHZOSFFI?cId=101 628&ts=42546&id=39460#

Its a thermostat but not a standard room stat its for underfloor heating so comes with a probe. I put the probe where I need it on my system and then set te temp on the LCD control panel and it will switch on and off to keep the temp as set. I will take it out of the case and mount it properly in adrive bay. Happy at last