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Me and a RaspberryPi: Introduction

People who follow me on Google+ might have noticed last night that I ordered a RaspberryPi board. This might sound strange, but the reason is simple: I needed a very small, very low power computer to set up a friend of mine with, for a project that we’ve decided to work on together, but let’s put this in order.

My friend owns a Davis Vantage Pro2 weather station, and he publishes on his website the data coming from it — up to now he’s been doing that with the software that comes with the station itself, which runs on Windows, and in particular on his laptop. So no update if he’s not at home.

So, what has this to do with a RaspberryPi board? Well, the station connects to a PC via an USB cable, connected in turn to an USB-to-serial adapter, which means that there is no low-level protocol to reverse engineer, and not only that, but Davis publishes the protocol specifications as well as a number of other documentation and SDKs for Windows and Macintosh.

It is strange that Davis does not publish anything for Linux themselves, but I found an old project and a newer one that seems to do exactly what my friend needs — the latter in particular does exactly what we need, which means that my task in all this is to set up a Gentoo Linux install (cross-compiled, of course) to run on that Pi and have wview to actually work on Gentoo — it requires some packaging, and more likely than not, some fixing.

Thankfully, I don’t have to start from scratch; Elias pointed out that we have a good page on the wiki with the instructions, even though they do not include cross-compilation pointers and other things like that that could be extremely useful. I’ll probably extend from there with whatever I’ll find useful beside the general cross compilation. Depending on whether I’ll need non-cross-compilable software I might end up experimenting with qemu-user for ARM chroots..

At any rate, this post serves as an introduction of what you might end up reading in this blog in the future, which might or might not end up on Planet Gentoo depending on what the topic of the single post is.

Comments 11
  1. You’ll want to check out proot as an alternative to chroot. It recently went into the tree.

  2. I have a very similar setup to this. There’s really very little to set up.I’ve got a David VPro2 as well, interfaced to a Raspberri PI. I did have it set up with my main Gentoo server earlier on but moved this to the PI when I moved the Weatherstation to not be sitting on top of my (warm) comms cabinet.The weatherstation will talk to Linux via a ttyUSB0 interface, using the cp210x kernel module.The software you’ll need to get data out of it is this:…This superseeds the Joe Jaworski version you have linked above, and is maintained and current. It compiles on x86_64 and arm (the PI). You won’t need to reverse engineer the protocol, because this app has it already all figured out.I just run vproweather over ssh (using rsa keys) to get real time data between the two devices.What would be very cool is if you could get vproweather pulled into portage though. That’s the main missing piece of the puzzle at the moment..

  3. Sounds cool. I’ve bought a Raspberry Pi for a similar reason. As you will go cross-compiling maybe some packages, maybe there will come some fixes on packages not cross-compilable.

  4. Have a friend I helped learn to build PC’s 12 years ago. He called me a couple weeks ago and has bought 3 of these PI’s (free shipping he said). Anyway he informs me he has asterisk working with a Google phone number and Ice Cream Sandwich on one of these. Also a PBX system installed and working (though the PBX voice menu needs some work), Oh yeah he said they have the wireless module on them and he uses wifi to his router on them. Apparently there is also a SIP program available thru Google Play and he can connect with and use a wireless handset.Anyway, lots of potential on that little device.

  5. Gentoo on the RPi is interesting, I think.I’ve just started getting stuff working as well. I’ve had a lot of help from the ambro-cross-overlay (….It doesn’t work out of the box with the instructions. But by making portage prefer the packages from the overlay you get a an arm environment cross-compiled.I’m thinking a somewhat working crossdev environment might aid me in making some binary packages for the Pi in the cases when distcc doesn’t work.

  6. I got a Pi a few weeks back and set it up with a cross-compiled Gentoo as well (basically following the Wiki Page you linked and the Gentoo Embedded Handbook). I use it as a simple NAS vith a pretty minimal setup.Back then I had trouble with the firmware in the git repo linked on the Wiki, the Pi would not boot at all and basic error blink codes did not work. I ended up using the firmware files (not the kernel) included in Raspian. It is probably fixed by now/I made a mistake somewhere and did not find. Just in case you need it, cost me quite some time to troubleshoot.

  7. Correcting the first comment.Pat runs a Debian for ARM on one Pi and has Asterisk on it. The SIP program is a d’load from Google Play for an Android phone. Using the Google Voice he recommended creating a mail account just for the phone so incoming chat and mail does not interfere.But then Asterisk can just PBX to the phone direct as well.

  8. P-L-E-A-S-E document this project as a How-To. I’m begging here. Two years ago I tried an ARM project and only succeeding in polluting the build computer with ATM code and the ATM partitiion with AMD64 code. Using qemu sounds incredibly slow, but I’ll do it if that’s what it takes. I once built gentoo native for a K-6 and it took four days to complete, but I do have a spare computer (AMD64) to devote to the build.

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