temperature control help

hi guys
i have a project to design a solution that will maintain the temp of a living space with a volume of 400m3 between 25-30 degrees centigrade.

i can use the following components.

LM35 Temperature sensor
LM358 operational amplifier
3x LM311 Comparators
74LS32 quad or gate
74LS04 hex NOT gate
2X12 volt relay

any help on a circuit design would be really appreciated.
THANKS

You didn't clearly describe the project.

A constant temperature of 25 to 30 deg/C means nothing but constant cooling in Thailand, at higher latitudes it certainly means heating.

What are you using for cooling/heating?

What is the required accuracy of the control device?

Boncuk

when the temperature rises above 30 we need a fan to kick in and when under 25 a heater. any ideas on a circuit using the components listed.

thanks

temperature help said:

when the temperature rises above 30 we need a fan to kick in and when under 25 a heater. any ideas on a circuit using the components listed.

thanks

Click to expand...

hi,
It should be possible to make a tempr controller using the parts you have listed.

You have not given details of the relay contacts or how much heating power/current you want to control.

Can you use different parts?

One part of your listed will do the job besides two low power transistors (to activate the relays).

Use the LM385 and make it a window comparator. Above window means temperature >30deg/C -> activate cooling fan, below window <25deg/C means heating.

Boncuk