Portable heater

[Aug3r]

I'm designing and building a (somewhat) portable heater for mah job. I have a low voltage heating element and (hopefully) a sufficient power supply. The area I'm hoping someone can help me with here is a temperature sensing circuit. I like the low voltage specifications of a thermocouple...but this device needs to monitor temperature changes in a 1 cu.ft. area, and I'm unsure of a thermocouples exact application.
IN addition. the temperature sensor is going to determine the voltage (voltage regulator) requirements for the heating element as well as a couple led's to indicate if the temperature drops below freezing. I'll continue to look through the massive database here and elsewhere...any help at all would be greatly appreciated!
Ok..maybe more info is required...
I'm using an LM34 to sense the temperature change...my range is from 40 F to 70 F
A 7805 will regulate the voltage to the heating element.

 

[Cry_Wolf]

Yes I think LM34 or LM35A will work fine for the temprature range you have mentioned

 

[audioguru]

5V at 1A is only 5W. It isn't much heat.

 

[Sceadwian]

For 1 cubic foot? Sounds likes plenty, depends on insulation granted.

 

[Aug3r]

The box IS heavily insulated. I'm still learning, so forgive my lack of knowledge...how do I get from the LM34 to the 7805 voltage regulator...is a comparator needed and do I need an omp amp prior to the comparator?

 

[Gordz]

Depending on accuracy a thermistor, transistor and relay would do. Then again, a PIC, FET and an LM75 would be better.