Category: Computers

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Maker Programming

Home Automation Mix-and-Match

This week I got a Wio Link prototype from a friend at Seeed Studio. It is an ESP8266-based little Internet of Things board with 6 Grove connectors for easy device connectivity, wifi networking, and controlled over an app & the Internet. For a quick project I wanted to hook it up with Home Assistant, an open source home automation platform that I read a lot about lately. The main focus was to have a first impression of both parts, and build up some experience for future, more serious projects.

The target solution: light up an LED if a particular person is at home location. Sort of a basic alarm system, though notice that the location of the LED was not mentioned – it can actually be anywhere in the world, as long as there’s Internet connectivity.

I’ve used the Wio Link, a Grove LED light, an Olimex OLinuXino Lime2 board running ArchLinux for the server, and a Buffalo router with DD-WRT system installed.

Wio Link

Wio Link was introduced in Seeed’s Kickstarter campaign, where they have raised more than 8x of their original target. It looks like a neat little board, and was happy to try out when I got my hands on one.

Their wiki page has quite a bit of information, so it was easy to get started. Connect to power, hold down the configure button till the LED lights up in a “breathing” pattern, connect through their Wio Link app, set up the wireless network settings and so on. Once connected, can define what kind of devices are attached to the board, and it looks like most of Grove devices are represented there. I only had a Grove LED at hand, so added it (“Generic Digital Output”), updated it, which created a new firmware and pushed onto the device.

Wio Link setup process (left to right): add device, update firmware, check status
Wio Link setup process (left to right): add device, update firmware, check status

The first update took a couple of minutes, but it’s pretty straightforward. The device then also has an API link, which brings up a web page with all the options to query, control, and reset the attached accessories (in my case that’s the one digital output).

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Maker Programming

Scratch Your Robot Itch

Recently I’ve been experimenting with the Scratch programming language, created by the Lifelong Kindergarten Group at MIT. It’s a fun environment that uses visual programming: drag-and-drop pieces of code blocks, and control objects on a stage, and the stage itself. It has quite a bit more depth to it, than the expression “visual programming language” implies, with it’s internal messaging system, multitasking, and event-driven approach. While it was originally aimed at creating interactive graphics and animations (see this TEDx talk by Prof. Mitch Resnick on the background), it is now evolving into new territories with the Scratch Experimental Extensions.

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Programming

Language of the Month: Rust, the results

Every now and then I do a “Language of the Month” feature when I spend one month to learn a new programming language. This last month in November I’ve spent with Rust, and it’s time to take stock. Will look at the impression I had in this short time, show one project that I get done in Rust, and some ideas what I’d like to do with Rust in the future!

Experience

According to my time log, I have spent about 20 hours this month learning Rust. That’s way too little to have a good understanding, but definitely enough to have some educated guesses (and excitement, and horror , as appropriate). This time I’m generally very impressed as Rust comes across as indeed a very modern and smart language, although that modernness is mostly in the tooling and non-essential parts. It is also changing very quickly, for good and bad. Here are some, admittedly subjective and incomplete list of observations. Good is what I like, Bad what’s less nice IMHO, and Ugly is what’s imperfect or confusing (at this stage of my Rust learning):

Good

It’s great to see that documentation is a not an afterthought, but a core part, that is making use a lot of modern development experience. Having a standard way to include example code in docstrings and actual tests are run on them to make sure the examples are also up-to-date with the code is a very cool concept. Also being able to auto-generate HTML documentation from the code is probably going to be standard in most new languages (I think Go does that also, and other languages have gained similar optional tools)

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Computers Lab

Dual Satellite NTP server with Navspark

A friend from NIST recently told me about a Raspberry Pi Stratum-1 NTP server project, and that reminded me of the experiments I did with the Navspark dual GPS+Beidou receiver module. Navspark is a small, Arduino-compatible module that besides GPS can also receive data from China’s Beidou 北斗 satellite navigation system , that is currently being built. I thought it would be fun to build a Beidou-powered Stratum-1 NTP server to see how does it compare to GPS.

Hardware

To have a really good really good, satellite-powered reference clock, I have to have access to a 1-pulse-per-second (1PPS) signal from the receiver. The pure USB-connected receivers don’t really seem to do that yet (looks like plenty of opportunities there!), instead I have to use separate hardware for it.

The Navspark module has a 1PPS pin (GPO3 below), and the only other pin I’ll really need is a serial pin to receive the NMEA stream of the satellite lock data (TXD1 below).

Detailed Navspark pinout with pin functions
Navspark pinout from the User Manual
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Learning Programming

Language of the Month: Rust

I found it hard to believe, that it’s been 4 years now since I finished the previous installment of “language of the month” column, in which I pick a programming language and dive in for a month to see something new. In that 4 years I have learned a lot of programming for sure – though probably very little computer science, and barely any new languages. It’s time to chance, and for the revival of this I’m checking out Rust.

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