Storage Room Exhaust Control.

Hello,
I would be very appreciative of any help and willing to pay to get my project to completion.

This is my second project on the Arduino, I've made a bread board prototype that controls a PC Fan but I really need this to control an industrial exhaust fan.

So far I have the display working and printing the Temp.
I need Help programming so as it gets hotter in the room the fan will speed up to try and keep it under 90 degrees Fahrenheit.
The Fan should start at 80 degrees Fahrenheit and max out at 100 F.
An LED should light when it's above 100 F.

Project requirements,
Display current temperature and possible fan speed percentage and max temp LED.

My fan speed is driven by 0-10volts.

Parts I have,
1 Arduino R3
2 OLED 0.96 inch 128x64 Yellow Blue Display.
3 LM35 Temp sensor
4 Elegoo Mega 2560 Starter Kit
5 Elegoo 37 Sensor Kit
6 Bridgold 50pc 10 type transistor Assortment Kit
7 24 Value 500pcs Capacitor Kit .1uF - 1000uF
8 KNACRO PWM-to-Voltage Module 0% -100% PWM Converted to 0-10V Voltage (PWM-to-Voltage)
9 OctagonStar L293D Motor Drive Shield for Arduino or UNO R3 AVR

Thank you!
Brian.

Get one of these: Neuhold Elektronik die Fundgrube für den Hobby-Elektroniker Temperaturschalter TSM 125 - you'll find them almost everywhere.

Thank you, but I already have 3 of those controlling fans that are just on or off.

The Fan I'm controlling is Variable speed Fan.

Or I interpreted that wrong as the link was in German I believe.

It's on/off, but it's cheap, works .. and if you can use some of them to power your fan - just 1 diode + different supply voltage.