johnkeefe.net

I like what's possible with triangles.

Playing with rectangular blinky grids is super fun, and I've made a weather monitor and a pulse-oximeter with those.

But there's something additionally awesome about the pattern possibilities with triangle pixels.

So when I saw a Hackaday post about building a clock display with LED triangles, I was hooked.

The short story is that I made it! It now lights up my living room with dazzling animations and a funky time display.

The longer story involves perseverance made possible by my coronavirus lockdown.

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At-home pulse oximeters, those fingertip devices doctors use to measure the oxygen saturation in your blood, have been selling out everywhere thanks to the Covid-19 pandemic.

But as my Quartz colleague Amirta Khalid points out in this great article, most people don't need 'em. If your oxygen level is worryingly low, you'll know — you don't need a machine to tell you. Folks with some existing conditions, however, can use a pulse oximeter to help a remote doctor monitor their vitals or to adjust supplementary oxygen devices.

When Khalid mentioned she was working the story, it reminded me of the DIY "pulse ox" sensor Sparkfun sells. It, like other pulse oximeters, shines light into the skin and makes measurements based on how that light is absorbed. I've built heartbeat-driven projects before and had been exploring new ways to monitor pulse rates. So I got one.

Sparkfun warns in red letters that "this device is not intended to diagnose or treat any conditions," and I offer the same caution if you're tempted to build one. The process wasn't hard at all. I got it running quickly ... and then added an LED display for fun and flourish.

Here's how I made it, and the code, too.

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Buy a new aquarium, and you often get hood lights that are ... meh. They're good enough, but not great.

There are plenty of high-quality replacement lights out there, but none of them had the nice, low profile of the plastic covers that came with this tank. So I decided to spruce up the existing illumination with some DYI lights — and even make them programmable with an Arduino.

That was more than a year ago. Now in coronavirus isolation, I finally made it happen.

Here's how.

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Several friends recently planned a party for maker, e-textiler and all-around awesome person Liza Stark — and I wanted to celebrate her with blinkies appropriate for the occasion.

The event was to take place in a rented house with a porch overlooking a slice of woods.

I decided to fill the trees with digital fireflies.

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How hot is a Harlem apartment?

We're trying to find out.

There are now DIY sensors in about 20 apartments, measuring the indoor heat and humidity -- in the middle of a heat wave.

It's the latest sensor journalism project from WNYC's Data News Team, in a collaboration with blog AdaptNY, community group WEACT and observation platform ISeeChange. 

And this week we worked with maker space HackManhattan, which hosted a soldering party to build more sensors.

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Between the last post and this one, I made a book!

Family Projects for Smart Objects is a collection of 11 projects based on Arduino hobby computers. They’re DIY activities designed for beginners who want to learn about sensors and make “Internet of Things” things.

Or just make stuff with people you love.

The book is currently with a team of designers who are working to make it beautiful, useful and fun.

Game plan is to publish in time for the World Maker Faire in New York this fall. If you’d like a note when it’s published, just jump onto my mailing list.

Ridiculously, that’s not all I’ve been doing. More posts ahead about cool (and hot) things I’m exploring at work and on the side.

Here's the high-wire act in which I describe the West Virginia University sensor-journalism project with 20 slides that advance automatically every 15 seconds. This took place in a room of brilliant thinkers at Newsgeist 2015 earlier this month in Phoenix.

More details about the sensor project are available on the StreamLab site and in an earlier blog post.

I stumbled on a fun, visceral way to show how Arduinos can sense and respond.

In preparation for a presentation at the Online News Association Conference in Los Angeles, I grabbed a Ping distance sensor I had in a bin. The Ping works like a bat — it emits an inaudible, high-frequency sound, and listens for the sound to bounce off an object. The round-trip time between ping and reflection reveals the distance.

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Yesterday the Streamlab class put do-it-yourself water monitors into Gatorade bottles and anchored them in the Monongahela River near Morgantown, West Virginia. They’re now texting their data readings live.

The link to the live chart is here, and the raw data is here.

We’re sensing conductivity, which is a good indicator of dissolved solids in the water, and temperature. The locations are: upstream of an industrial site, downstream of the same site and further downstream below the Morgantown lock and dam. 

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A summer of tinkering has culminated with a conductivity and temperature sensor that texts its data from inside a Gatorade bottle.

The contraption consists of a Riffle, which is an Arduino-like board designed to fit through the mouth of a water bottle and a Fona cell-phone board. And a bottle.

The plan is to submerge several of these along a stretch of the Monongahela River as part of a sensor-journalism class at West Virginia University. It’s a work in progress, but you can [see how things are going]. My job was to build a working conductivity sensor that would report its findings live. Here are the components and how I made it go.

Update: We actually deployed some of these sensors in a river!

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