raspberry pi

1627 Articles

Bathroom Status Reporting Hack Eliminates Lines, Frustration

September 4, 2016 by 20 Comments

In a lot of ways, portable toilets are superior to standard indoor-plumbing-style toilets. This is mostly due to the fact that they have a status indicator on the door. It’s a shame that no indoor bathrooms have figured this out yet, especially in office buildings where your awkward coworkers bang on every door rather than just check for feet in the huge gap that for some reason exists between the floor and the stall door. Anyway, [Chris] and [Daniel] came up with a solution for this issue, which also eliminates wait time for bathrooms in their office.

Their system is an automated bathroom status indicator that reports information about the bathroom’s use over WiFi. Since the bathrooms at their facility are spread out, it was helpful to be able to look up which bathroom would be free at any given moment. Several Raspberry Pis form the nerves of the project. Custom sensors were attached to a variety of different door locks to detect status. Each Pi reports back over WiFi. This accomplishes their goal of being subtle and simple. They also point out that they had to write very little code for this project since there are so many Unix and embedded hardware tools available to them. Checking the status of the bathroom can be as simple as running netcat.

If you’re looking to roll out your own bathroom status monitor solution, [Chris] and [Daniel] have made their code available on GitHub. There are a number of other ways to automate your bathroom, too, like switching the exhaust fan on when it gets too smelly or humid, or even creating a device that dispenses your toilet paper for you.

 

How To Use Docker To Cross Compile For Raspberry Pi (and More)

September 1, 2016 by 17 Comments

It used to be tedious to set up a cross compile environment. Sure you can compile on the Raspberry Pi itself, but sometimes you want to use your big computer — and you can use it when your Pi is not on hand like when on an airplane with a laptop. It can be tricky to set up a cross compiler for any build tools, but if you go through one simple step, it becomes super easy regardless of what your real computer looks like. That one step is to install Docker.

Docker is available for Linux, Windows, and Mac OS. It allows developers to build images that are essentially preconfigured Linux environments that run some service. Like a virtual machine, these images can run together without interfering with each other. Unlike a virtual machine, Docker containers (the running software) are lightweight because they share the same underlying kernel and hardware of the computer.

The reality is, setting up the Raspberry Pi build environment isn’t any easier. It is just that with Docker, someone else has already done the work for you and you can automatically grab their setup and keep it up to date. If you are already running Linux, your package manager probably makes the process pretty easy too (see [Rud Merriam’s] post on that process). However, the nice thing about the images is it is a complete isolated environment that can move from machine to machine and from platform to platform (the Windows and Mac platforms use a variety of techniques to run the Linux software, but it is done transparently).

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Internet Of Things Woodworking

August 31, 2016 by 18 Comments

Woodworking is the fine art of building jigs. Even though we have Internet-connected toasters, thermostats, cars, and coffee makers, the Internet of Things hasn’t really appeared in the woodshop quite yet. That’s changing, though, and [Ben Brandt]’s Internet of Things box joint jig shows off exactly what cheap computers with a connection to the Internet can do. He’s fully automated the process of making box joints, all with the help of a stepper motor and a Raspberry Pi.

[Ben]’s electronic box joint jig is heavily inspired by [Matthias Wandel]’s fantastic screw advance box joint jig. [Matthias]’ build, which has become one of the ‘must build’ jigs in the modern woodshop, uses wooden gears to advance the carriage and stock across the kerf of a saw blade. It works fantastically, but to use this manual version correctly, you need to do a bit of math before hand, and in the worst-case scenario, cut another gear on the bandsaw.

[Ben]’s electronic box joint jig doesn’t use gears to move a piece of stock along a threaded rod. Stepper motors are cheap, after all, and with a Raspberry Pi, a stepper motor driver, a couple of limit switches, and a few LEDs, [Ben] built an Internet-enabled box joint jig that’s able to create perfect joints.

The build uses a Raspberry Pi 3 and Windows IoT Core to serve up a web page where different box joint profiles are stored. By lining the workpiece up with the blade and pressing start, this electronic box joint jig automatically advances the carriage to the next required cut. All [Ben] needs to do is watch the red and green LEDs and push the sled back and forth.

You can check out [Ben]’s video below. Thanks [Michael] for the tip.

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Pan And Tilt With Dual Controllers

August 30, 2016 by 14 Comments

It wasn’t long ago that faced with a controller project, you might shop for something with just the right features and try to minimize the cost. These days, if you are just doing a one-off, it might be just as easy to throw commodity hardware at it. After all, a Raspberry Pi costs less than a nice meal and it is more powerful than a full PC would have been not long ago.

When [Joe Coburn] wanted to make a pan and tilt webcam he didn’t try to find a minimal configuration. He just threw a Raspberry Pi in for interfacing to the Internet and an Arduino in to control two RC servo motors. A zip tie holds the servos together and potentially the web cam, too.

You can see the result in the video below. It is a simple matter to set up the camera with the Pi, send some commands to the Arduino and hook up to the Internet.

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Raspberry Pi Hive Mind

August 29, 2016 by 34 Comments

Setting up a cluster of computers used to be a high-end trick used in big data centers and labs. After all, buying a bunch of, say, VAX computers runs into money pretty quickly (not even counting the operating expense). Today, though, most of us have a slew of Raspberry Pi computers.

Because the Pi runs Linux (or, at least, can run Linux), there are a wealth of tools out there for doing just about anything. The trick is figuring out how to install it. Clustering several Linux boxes isn’t necessarily difficult, but it does take a lot of work unless you use a special tool. One of those tools is Docker, particularly Docker Swarm Mode. [Alex Ellis] has a good video (see below) showing the details of a 28 CPU cluster.

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Hackaday Links: August 28, 2016

August 28, 2016 by 19 Comments

E-paper looks awesome, but it’s a pain to work with. You need only look at the homebrew implementations of e-paper drivers and the mess of SMD components for proof of that. [jarek] wanted to play around with e-paper and developed this tiny little driver for a Teensy. It’s a fun toy, and the simplest possible circuit necessary to drive this particular e-paper module.

I am once again asking if anyone knows where to buy this computer case. No, not a complete system – I just want the case, folding keyboard, and monitor integrated into an mATX enclosure.

Back in 1985, a young [Matthias Wandel] built a remote control forklift out of a few windshield wiper motors, wood, and not much else. He’s rebuilt this toy recently, just to prove you can build anything with a stack of plywood and a wood gear template generator.

More Adafruit muppets they probably can’t call muppets. Yaaay. This time it’s J is for Joule. Watts that? A second.

The Raspberry Pi Project, one of our favorite projects in the Hackaday Prize that uses a Raspberry Pi, one of the most liked, viewed, and followed projects on Hackaday.io, and a technological tour de force the likes of which have not been seen since the invention of the steam engine got an update this week. [Arsenijs] and the rest of the Raspberry Pi Project team have released a version of their Raspberry Pi pinout helper. Previously, this tool was only used internally to the project, but since this pinout helper has such far-reaching utility they’ve decided to release a public version. Truly, they are kings among men.

This is possibly the coolest use of stacked plywood I’ve ever seen. It’s a spiral staircase, with each step made of 12 layers of plywood. The ‘spine’ of this staircase is a 3″ sch 40 steel pipe, with a proper foundation. The layer of ply are adhered to the pipe with construction adhesive, and each layer of ply is glued together with wood glue. No, it’s not up to code yet, but it was cheaper to build than just buying a spiral staircase.

[Brek] wrote a graphics library for the ubiquitous 128×64 monochromatic LCDs. It’s written for PICs, but damned if we can’t find a link to the library itself. Hopefully [Brek] will jump in the comments below.

Those really, really cheap ESP8266 modules only have 512kB of Flash in them. Here’s how you upgrade those modules to 4MB. You can do it without a hot air gun, and all you need is a few cheap Flash chips.

Here’s a sound card for a Raspberry Pi. No, that’s not a completely dumb idea. This sound card uses quality op-amps, 24-bit ADCs and DACs, and has MIDI. If you’re experimenting with Pure Data or any other Linux audio toy, this could be a useful addition to your Pi stack.

Weather-aware Shoe Rack Helps You Get Ready For The Day

August 27, 2016 by 8 Comments

If you’re anything like us, your complete shoe collection consists of a pair of work boots and a pair of ratty sneakers that need to wait until the next household haz-mat day to be retired. But some people have a thing for shoes, and knowing which pair is suitable for the weather on any given day is such a bother. And that’s the rationale behind this Raspberry Pi-driven weather-enabled shoe rack.

The rack itself is [zealen]’s first woodworking project, and for a serious shoeaholic it’s probably too small by an order of magnitude. But for proof of principle it does just fine. The rack holds six pairs, each with an LED to light it up. A PIR sensor on the top triggers the Raspberry Pi to light up a particular pair based on the weather, which we assume is scraped off the web somehow. [zealen] admits that the fit and finish leave a bit to be desired, but for a first Rasp Pi project, it’s pretty accomplished. There’s plenty of room for improvement, of course – RFID tags in the shoes to allow them to be placed anywhere in the rack springs to mind.

[via r/raspberry_pi]