measuring the temperature of a fry pan

My name is yuval and my arduino project focuses on helping blind people cook. The prototype is helping them fry an omelet. I need to measure the temperature of a fry pan to know when she is hot and i can start cooking. what sensor do you think i should use? there are plenty of temperature sensors and i am not sure about the differences. if anyone has a code or part of a code that seems relevant and he can upload it to here it will be very helpful for us :)

At those temperatures you have 2 choices, RTD (resistance temperature detectors) or thermocouples.

Either will need extra electronics to interface with an Arduino. RTDs need an amplifier and thermocouples need amplification and cold junction compensation.

One more type of sensor https://en.wikipedia.org/wiki/Infrared_thermometer.

I would go for a Panasonic Grid-Eye sensor in a fixed position above the stove. Then it can see the status of all 4 burners and you could program some nice warnings when the stove is hot, with no pan on it.

For a school project, I would not attempt to do that - just measure the hottest point on the Grid-Eye and report that. But you can show to the teacher how it can be extended to do more than just one frypan and get extra credit for that without actually doing the (hard) work.

Whandall:
One more type of sensor Infrared thermometer - Wikipedia.

One proviso: for a plain metal pan without a coating, IR is no use for measuring temperature, metal
just reflects IR. For a non-stick coating it probably will work fine, and the sensor can be permanently
mounted over the cooker which is much more convenient.

MarkT: One proviso: for a plain metal pan without a coating, IR is no use for measuring temperature, metal just reflects IR.

Basically it is not the reflected IR that is should be measured, it is the emitted IR. Other sources of IR may be reflected on the metal and make the measurement hard to impossible.