Back near Christmas last year, I purchased my first Raspberry Pi as a test to see if I could build a Minecraft Server for our family. It worked, but the 1GB version I purchased would only support one player at a time. It could support two if the household LAN had little other traffic.
This past weekend, I purchased the 4GB Raspberry Pi 4 in the hopes that would solve much of my problems. It did. I think we can now support the five total players that I care to admin.
However, lo and behold, it left me with this perfectly good Raspberry Pi 4 left over. What will I ever do now? You can bet your sweet bippy that I'm going to put it to work doing something.
In perusing Raspberry Pi's downloads, I discover that there is now an Ubuntu Server version just for my Pi. I have nothing against Raspbian. It serves our needs on the MinePi server well, but for my own uses, I'd rather use Ubuntu. I downloaded the image, got it stuck onto my microSD card and loaded up the Pi.
I had a little difficulty as I didn't have an HDMI monitor, nor a keyboard at home to use. I did manage it with a tweak to /etc/netplan (yes, dangerous move) and an Ethernet cable. It worked and I'll try to write that article later today, if time permits.
I am up early this morning (because I'm always up early) and decided to start the work of configuring my new Pi server. After getting aptitude loaded, I wanted to see about CPU temp. I'm not running this one with a fan or box just yet. It's just a test bed, but that means I need to watch the temperature closely.
I found out quickly that vcgencmd isn't in the repository and regular sensor apps probably wouldn't work. This is an ARM, not an Intel clone.
Did some digging and found a bash script on NixCraft that showed where the CPU temp is kept in the file system. They offered a small bash script to convert the stored integer into Celsius. I tried it out on my Pi and it worked. But...
I'm not a Celsius person. I'm a Fahrenheit person.
Not to mention, I discovered on the article that vcgendcmd gives you the GPU temp, not the CPU temp. I still have that one to figure out. But at least I have one of the pair. Considering they are on the same chip, probably shouldn't matter, but better safe than sorry.
In any case, with a little bash tweaking, I came up with the following script:
echo "Raspberry Pi CPU Temp"
cpu=$(</sys/class/thermal/thermal_zone0/temp)
celsius=$((cpu/1000))
echo "Temp in Celsius"
echo "$((cpu/1000)) C"
echo "Temp in Fahrenheit"
echo "$((celsius*9/5+32)) F"
It worked! My CPU, sitting vertical on the kitchen counter, is running a balmy 111 degF (44 degC). I also added a little extra wording so that I can read it well with my bad eyes.
So, use it if you like. I think I might change it into a C program or python program later, just for practice; maybe even a temperature logger and alarm?
I've included a link to the NixCraft article below as well as a link to Raspberry Pi's download page that has links to the OS's one can use on the Pi.
Happy Monday!
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