Meshtastic And Owntracks To Kick Your Google Habit

I have an admission to make. I have a Google addiction. Not the normal addiction — I have a problem with Google Maps, and the timeline feature. I know, I’m giving my location data to Google, who does who-knows-what-all with it. But it’s convenient to have an easy way to share location with my wife, and very useful to track my business related travel for each month. What we could really use is a self-hosted, open source system to track locations and display location history. And for bonus points, let’s include some extra features, like the ability to track vehicles, kids, and pets that aren’t carrying a dedicated Internet connection.

You can read the title — you know where we’re going with this. We’re setting up an Owntracks service, and then tying it to Meshtastic for off-Internet usability. The backbone that makes this work is MQTT, a network message bus that has really found its niche in the Home Assistant project among others. It’s a simple protocol, where clients send brief messages labeled by topic, and can also subscribe to specific topics. For this little endeavor we’ll use the Mosquito MQTT broker.

One of the nice things about MQTT is that the messages are all text strings, and often take the form of JSON. When trying to get two applications to talking using a shared MQTT server, there may need to be a bit of translation. One application may label a field latitude, and the other shortens it to lat. The glue code to put these together is often known as an MQTT translator, or sometimes an MQTT bridge. This is a program that listens to a given topic, ingests each message, and sends it back to the MQTT server in a different format and topic name.

The last piece is Owntracks, which has a recorder project, which pulls locations from the MQTT server, and stores it locally. Then there’s Owntracks Frontend, which is a much nicer user interface, with some nice features like viewing movement a day at a time. Continue reading “Meshtastic And Owntracks To Kick Your Google Habit”

Tiny Linux On A No-MMU RISC-V Microcontroller

In the vast majority of cases, running a Linux-based operating system involves a pretty powerful processor with a lot of memory on hand, and perhaps most importantly, a memory management unit, or MMU. This is a piece of hardware which manages virtual memory, seamlessly giving each process its own memory sandbox in which it shouldn’t be able to rain on its neighbours’ parade. If there’s no MMU all is not lost though, and [Uros Popovic] gives us a complete guide to building the MMU-less μClinux on a RISC-V microcontroller.

The result is something of a Linux-from-scratch for this platform and kernel flavour, but it’s so much more than that aside from its step-by-step explanation. It’s probable that most of us have heard something of μClinux but have little direct knowledge of it, and he leads us through its workings as well as its limitations. As examples, standard ELF binaries aren’t suitable for these systems, and programmers need to use memory-safe techniques.

Whether or not any of you will run with this guide and build a tiny MMU-less Linux system, anything which expands our knowledge on the subject has to be a good thing. it’s not the first time we’ve seen a RISC-V microcontroller turned to this task, with a nifty trick to get round the limitations of a particular architecture.

Dumping Spacecraft In The Middle Of Nowhere

The BBC has an interesting article on Point Nemo, AKA the Oceanic Pole of Inaccessibility, AKA the spacecraft graveyard. This is the place in the ocean that is furthest from land, in the middle of the usually stormy South Pacific. It’s as far out there as you can get without leaving the planet: about 2,688 kilometers (1670 miles) from the nearest dry land. Even the ocean floor is 4 km (2.5 miles) down; the closest human life is the International Space Station (ISS) astronauts flying 415 km (260 miles) above it. It is not near any shipping lanes or transport routes. It is, to put it bluntly, the middle of goddam nowhere. So, it is a perfect place to dump derelict spacecraft.

Since 1971, over 160 spacecraft have met their end in these chilly waters, from the fiery public end of the Mir space station to the secret death of numerous secret spy satellites. The article in question focuses on the Soviet satellites, but plenty of other countries dump their end-of-life satellites there, including trash from the ISS. The Chinese Taingong-1 space station crashed nearby, although that was more by accident than design. The ISS is scheduled to join its trash in a few years: the current plan is that the massive space station will be de-orbited and crashed near Point Nemo in 2030.

Will there be anyone to see it? When the Mir space station was de-orbited, some entrepreneurial companies offered flights to the area to catch a glimpse, but the best view was from the island of Fiji. So, start planning your trip now…

Continue reading “Dumping Spacecraft In The Middle Of Nowhere”