Sorry, this is not about raspberry pie, but a computer, here is a link to what I am talking about https://www.raspberrypi.org/ . I was thing the today about the issue of tracking temperature and other related things. Could a raspberry pi be set up for less than $100 that could track temperature over a two week period or longer? Also could this run for about a week or two without the need of a human to check in on it?
You should never forget that every creature has its purpose in the cycle of nature and can also be very important to humans. Sepp Holzer's Permaculture
I have seen a lot of sensors that plug into a Raspberry Pi. A friend of mine used one to monitor his greenhouse temps while he was at work. He did the programming himself, in Python (?), as I vaguely recall. I don't recall if he logged data on the Pi itself, but with the right programming I would guess there's no reason why it can't be done. I have no idea about cost, though.
I've seen tiny data loggers with thermometers or other instruments attached for research. Would love to find something simple and effective that can monitor and record temp, and possibly other things as well.
I have a Raspberry Pi, but I'm currently using it for other things (it's plugged into my router providing DNS and DHCP, as well as a web server). I've thought about doing what you're suggesting, though I haven't taken much time to dig into it yet.
I'm sure it can be done, provided that you have the time and patience to learn how to set it all up.
Newegg has a temp/humidity sensor for $15 -https://www.newegg.com/p/2DS-007X-00659
You might need longer cables for the sensors, depending on the conditions in the place you're trying to monitor (I doubt the Pi would appreciate excessive temperature swings or humidity, though a more robust case could probably mitigate some of that). The components above are just examples, no idea if they are the best options price-wise or otherwise. The big expense will be the Pi itself...the peripherals are (generally) cheap.
It would be a decent amount of work on your part, you have to plan out where the sensors will be, where the Pi would be installed, and how to connect them to power (and probably your LAN). You then have to learn how to read data from the sensors and write it out to a data file. After that, you can decide how you want to process the data - there are various libraries out there to help with data visualization, or you could just feed it into a spreadsheet and manually process it (but what's the fun in that, when you could make the computer do it for you?). As far as timing goes, there's really no limit. As long as your power stays on and nothing eats the wires or anything, you're "constrained" by the size of the SD card that you installed, which, unless you buy a tiny card that can barely hold the operating system, should hold plenty of data - text is small, and it can be compressed to even smaller sizes. If you run out of space on the pi, just push it over the LAN to another computer, or get a bigger SD card, or plug a drive into the pi (though be careful with that, though, you may run yourself out of power).
I would love to actually do this someday, but I have kids and chickens and gardens and a house to take care of, so it probably won't make it near the priority list for a while.
I experimented with using a raspberry pi for temperature and humidity monitoring about 4 years ago, it seems like my goals may have been similar to yours. I wanted to log temperatures and humidity from a few different locations on my farm in california, and I didn't want to pay for one of the expensive monitoring subscription systems. I never got the system working very well, and spent many hours and about 350 dollars in parts, and I am somewhat competent programmer. Keep in mind that this is a bit outdated now, but I settled on using the raspi as the hub, and arduinos for the sensors (they are smaller and cheaper). I bought most of it from sparkfun. I was using BTLE (low energy blue tooth) chips to communicate because I figured I could get all of my devices within a couple hundred feet of the hub. I bought small Li-Ion battery packs for each arduino and planned to have the hub in my office at the center of the property. I also bought a breadboard, some resistors, and some other things to help me learn how to build and program the sensors. I got everything working fairly well, but ended up getting distracted with other projects, and haven't gotten back to it (even though it's still on "the list"). Now i'm building a batch box, and have a 9 week old puppy, and I've been trapped on the Canadian side of the border for a year and have no idea when I'll get back to my projects in California..
From my experience I would say that it may be possible to do this for under 100 dollars in some form with enough time investment and expertise in microcontrollers, but that is a stretch. I spent 350 dollars, and about 20 hours on it, with no direct experience but 13 years of Linux programming and I didn't quite get there. I believe I left the project at the phase of figuring out a housing for the arduinos, with their battery packs, BTLE chips and temp/humidity sensors. I duct taped one of them into a ball, but disconnected a sensor in the process and I don't think that would last for very long with high humidity anyway. I know there are tons of designs for printing housings for raspis online, and I think that would be a good way to go if one were to pursue this project more seriously.