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i think it is not too difficult.for example,a temprature logger,you need a sensor,which can be a diode ,or a chip such as LM334.so you can get a temp-voltage signal,then you can conver the voltage signal to digital signal,use a AD converter.it is a good idea to use a cpu that can do that job.then you need a low power CPU,depends on what link power you use.if you use a big power supply such as a car battery,a cpu like 8251 is enough.if you use AAA size battery,you must use a low power cpu,such as TMS430 from TI(w*w.ti.com).the w*w.microchip.com also have good cpu for this design.then you need a memory to record the data,which can be a flash memory or a eeprom ,the size you can decide from the data you want to record.you can use a lcd to display the result ,if you can,design a sample keyboard ,can do many things.then do not forget a rs232 ,which can interface with your PC.if so ,you can get the data in your PC,then you can do a lot of things using the data in the PC platform.
can this help you?i hope so.
Maxim/Dallas do a logger that is exactly what you need. No interfacng from a micro. All youu need is a DS1615 chip (or similar in the raange) and a rs232 to ttl convertor. Do a simple program in visual basic and you can get temperature data. There is also a rtc on board, battery info. I built one with a lithium cell and it has been running for almost 3 years!
I have a routine that i wrote in visual basic that you can use to get the information off the device.
Other than that you can use a MCU and this same device or a descrete temperature IC. See microchips appnotes. There is a way to do a crude temperature measurement using the watchdog timer. I guess it all depends on the accuracy you are requiring.
I agree with Bagster, Maxim/Dallas have a couple of good application notes that could help you. In particular look for there PC Printer Port Controls Data Logger app note, under there website "h**p://www.maxim-ic.com/appnotes.cfm/appnote_number/142" it does not require a MicroController and they are good about sampling you all the needed IC's.