DIY I2C Devices With ATtiny85

November 7, 2016 by Elliot Williams 31 Comments

[Pawel] has a weather station, and its nerve-center is a Raspberry Pi. He wanted to include a light sensor but the problem is, the Pi doesn’t have a built-in ADC to read the voltage off the light-dependent resistor that he (presumably) had in his junk box. You can, of course, buy I2C ADC chips and modules, but when you’ve already got a microcontroller that has ADC peripherals on board, why bother?

[Pawel] wired up a tremendously simple circuit, downloaded some I2C slave-mode code, and added an LED for good measure. It’s all up on GitHub if you’re interested.

cropped_shot_2016-10-21-112958 — Bright by Day, Dark by Night!

We’re covering this because we rarely see people coding for I2C slave devices. Everyone and their mom uses I2C to connect to sensors, for which the Arduino “Wire” library or “i2c-tools” on the Pi do just fine. But what do you do when you want to make the I2C device? [Pawel]’s project makes use of TinyWireS, a slave-mode SPI and I2C library for AVR ATtiny Arduino projects.

Here, [Pawel] just wanted a light sensor. But if you’re building your own devices, the sky is the limit. What’s the most esoteric I2C sensor that you can imagine? (And is it really the case that we haven’t seen an I2C slave device hack since 2010?)

Hackenings: Retro Gaming And Computing

November 5, 2016 by Elliot Williams 5 Comments

[Strages] contacted us via IRC on the #Hackerspaces channel to let us know that Makers Local 256, his hackerspace in Huntsville Alabama, is having their annual Retro Gaming and Computing Night this week: November 12th from 4pm to 11pm.

Nothing makes us feel old like seeing Starcraft tossed in with the "retro" games category, but if they set up a LAN for three-way Zerg-Terran-Protoss action, we’ll abide. If you’re anywhere near Huntsville, you should head on down and show off your hard-earned skills.

Hackenings

"Hackenings" is our weekly roundup of what’s going on in hackerspaces around the world. If you’ve got an event that you’d like to see on these pages, write to tips@hackaday.com with [Hackenings] in the subject line, and awesome images or graphics if you’ve got ’em. And tune in again next Saturday to see what’s going on in (y)our world.

Hackit: Laser Cut Your Own Jigsaw Puzzle

November 5, 2016 by Elliot Williams 19 Comments

If you have a laser printer, you’ve got your Christmas presents sorted out. At least if your family likes jigsaw puzzles. The idea is very simple, laminate a photograph onto some laser-cuttable board, and then run the laser over the outline of the pieces. Bam! Instant puzzle.

The trick is generating the puzzle outline, and of course there’s an online application for that. It’s got options that let you customize the piece count and shapes, and then download the result as an SVG image.

Unfortunately, it’s closed-source and makes the pieces a little bit too uniform for our liking — many of the pieces have exactly the same shape as each other. Are you up to the challenge of writing a better one? We’d love to see it, because the idea of a simple puzzle overlay for laser cutters is too good. Help us get started with some brainstorming in the comments below. How do you go about generating meaningfully unique jigsaw edges algorithmically?

Once you’ve got the puzzle cut out, you can seal up the surface nicely, toss it in a box, and then you’ve got a personalized present. To put it together, we suggest an accompanying DIY pick-and-place tool. (And kudos to [Kristina] for the best headline of 2015 on that one!)

Thanks to Hackaday alum [George Graves] for the tip!

ESP32 Modules Popping Up Everywhere, In Stock Almost Nowhere

November 2, 2016 by Elliot Williams 46 Comments

We know what it’s like to wait for newly released electronic parts. Clicking refresh every day at your favorite online retailers, reading reviews published by the press who got preview units, and maybe even daring to order implausibly cheap devices from foreign lands. The ESP32 has many of us playing the waiting game, and we’ll level with you — they’re out of stock most places. But, if you look hard enough you can find one. At least, you could find them before we wrote this quick roundup of ESP32 hardware. If hearing about parts that are just out of reach is your sort of thing, then read on, you masochist!

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FingerRing Is Simplest Multichannel Mixer

November 1, 2016 by Elliot Williams 16 Comments

It’s hard to make an audio mixer with any less technology than FingerRing (YouTube video, embedded below). We’re pretty sure that [Sergey Kasich] isn’t going to get a patent on this one. But what he does get is our admiration for pushing a simple idea far enough that it’s obviously useful.

The basic idea is transmitting signals using the human body as a conductor. What [Sergey] does is lay out multiple sound sources and sinks on the table, and then play them like a mixer made musical instrument. Pressing harder reduces the resistance, and makes the sound louder. Connecting to two sources mixes them (in you). Watch the video — he gets a lot of mileage out of this one trick.

Continue reading “FingerRing Is Simplest Multichannel Mixer” →

What’s New, ESP-32? Testing The Arduino Library

October 31, 2016 by Elliot Williams 30 Comments

In case you missed it, the big news is that a minimal Arduino core is up and working on the ESP32. There’s still lots left to do, but the core functionality — GPIO, UART, SPI, I2C, and WiFi — are all up and ready to be tested out. Installing the library is as easy as checking out the code from GitHub into your Arduino install, so that’s exactly what I did.

I then spent a couple days playing around with it. It’s a work in progress, but it’s getting to the point of being useful, and the codebase itself contains some hidden gems. Come on along and take a sneak peek.

Continue reading “What’s New, ESP-32? Testing The Arduino Library” →

Put That Amateur Radio License To Use On 915 MHz

October 31, 2016 by Elliot Williams 106 Comments

Amateur radio enthusiasts in the US will be interested in Faraday, an open-source digital radio that runs on 915 MHz, which amateur radio enthusiasts may know better as the 33 cm band.

You can transmit on 915 MHz without a license (in the US), taking advantage of the Industrial, Scientific, and Medical (ISM) exemption. This means that there’s commodity hardware available for sending and receiving, which is a plus. But you can’t do so with any real power unless you have an amateur radio license. And that’s what makes Faraday interesting — it makes it very easy to transmit and receive digital data, with decent power and range, if you’re licensed. The band is currently under-utilized, so go nuts!

The hardware design and documentation is online, and so is the firmware. The founders of the project would like you to build out a big network of these devices, possibly meshing them together. Our only regret is that the 33 cm band is only really open for use in the US, both with a license and without. Of course, there’s very little the Faraday team can do about that.

We’re no strangers to digital-mode amateur radio around here. But if you’re an amateur who hasn’t played around with digital modes yet, this might be a good way to get your feet wet.

Thanks to [Daniel] for the tip!