Raspberry Pi Home Automation For The Holidays

January 13, 2017 by Elliot Williams 2 Comments

When you want to play around with a new technology, do you jump straight to production machinery? Nope. Nothing beats a simplified model as proof of concept. And the only thing better than a good proof of concept is an amusing proof of concept. In that spirit [Eric Tsai], alias [electronichamsters], built the world’s most complicated electronic gingerbread house this Christmas, because a home-automated gingerbread house is still simpler than a home-automated home.

Yeah, there are blinky lights and it’s all controlled by his smartphone. That’s just the basics. The crux of the demo, however, is the Bluetooth-to-MQTT gateway that he built along the way. A Raspberry Pi with a BTLE radio receives local data from BTLE sensors and pushes them off to an MQTT server, where they can in principle be read from anywhere in the world. If you’ve tried to network battery-powered ESP8266 nodes, you know that battery life is the Achilles heel. Swapping over to BTLE for the radio layer makes a lot of sense.

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Portable RetroPie Builds On The Shoulders Of Giants

January 12, 2017 by Bryan Cockfield 36 Comments

For anyone wanting to get that shot of nostalgia without the hassle of finding an NES Classic, the Retropie project is a great starting point. Of course, it’s not too noteworthy to grab a Raspberry Pi, throw a pre-built distribution on it, and plug in an SNES to USB converter. What is noteworthy, however, is building a Retropie that’s portable and that has the quality and polish of the latest build from [fancymenofcornwood].

For starters, the laser cut wood case was custom-made. From there, all of the PCBs were fitted including specific ones to handle each set of buttons (complete sets of D-pads, shoulder buttons, and joysticks) and another for the 5″ HDMI screen. It has stereo speakers and its own headphone jack (to the envy of all new iPhone owners), and is powered from a Raspberry Pi 2 running Retropie 4.1. The battery pack shouldn’t leave you stranded, either, especially not if you grew up playing the Sega Game Gear.

The quality of the build here is outstanding, and its creator made a design choice to make it easily replicable, so if you’ve wanted to play N64 or PS1 games while on the go, this might be what you’ve been waiting for. There are lots of other options for getting some fun from a Retropie going though, from building one into a coffee table to re-purposing that infamous Game Gear.

Obligatory clip of this portable playing Doom is found after the break.

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Give Your Raspberry Pi A Good Hammering

January 9, 2017 by Jenny List 196 Comments

One of the features of the Raspberry Pi Zero is that it arrives with no GPIO header pins installed. The missing pins reduce the price of the little computer, as well as its shipping volume. A task facing most new Pi Zero owners has therefore been to solder a set of pins into the holes, and indeed many suppliers will sell you the pins alongside your new Zero.

The British Pi accessories supplier Pimoroni think they may have a solution to this problem, with a set of solderless pins that the user is expected to fit by tapping both pins and Pi with a hammer. Each pin is designed to deform under pressure, and grip the through-plated walls of the hole in the PCB. In reality they are push-fit pins designed to be fitted with a press or a special tool, but since the average Zero buyer will have neither they supply a small laser-cut jig and give instructions to tap carefully with a pin hammer or similar. They have a demonstration as part of their regular Bilge Tank podcast, which we’ve included below the break.

Pins like these can be quite reliable when installed with the proper tools. They are often used in military and aerospace systems. In this case though, we expect that a chorus of you will be limbering up to comment that it would be far better to solder the connector, and we can’t help agreeing with you. Of course this product isn’t really marketed at Hackaday readers. Instead, the target market of a board like the Zero are children. For them soldering may well be a step too far. We can’t help wondering though whether hammer installation will deliver a reliable enough contact, and whether we’ll see a horde of youngsters whose Pi HATs don’t work due to dodgy connectors. Aside from the ones who’ve broken their Zeros with hammering that was a bit enthusiastic, that is.

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Air Conditioner Speaks Serial, Just Like Everything Else

January 6, 2017 by Lewin Day 26 Comments

Like so many other home appliances, it’s likely that even your air conditioner has a serial interface buried inside it. If you’re wondering why, it’s because virtually every microcontroller on the planet has a UART built in, and it’s highly useful for debugging during the development process, so it makes sense to use it. Thus, it was only a matter of time before we saw a hacked airconditioner controlled by a Raspberry Pi.

[Hadley] was growing frustrated with the IR remote for his Mitsubishi air conditioner; it can issue commands, but it’s a one way interface – there’s no feedback on current status or whether commands are received, other then the occasional beep or two. Deciding there had to be a better way, [Hadley] grabbed a Saleae Logic Analyser and started probing around, determining that the unit spoke 5 V TTL at 2400 bps with even parity. The next step was to start talking back.

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Alexa Robot Coffee Maker Brews Coffee, Speaks For Itself

January 6, 2017 by Steven Dufresne 16 Comments

To keep hackers fueled and hacking, why not hack a coffee maker into a coffee brewing robot? [Carter Hurd] and [David Frank] did just that at The Ohio State’s Hack OHI/O 24 hour Hackathon. They even won the “Best Hardware Hack”. The video below shows it in action but the guys sent us some extra details on how it’s made.

Alexa coffee maker robot

The electronics

To give it a voice they put Alexa on a Raspberry Pi. Using an audio splitter they have the voice go both to a speaker and to an Arduino. The Arduino then uses the amplitude of the audio signal’s positive values to determine how much to open the “mouth”, the coffee maker’s hinged cover. As is usually the case, there’s some lag, but the result is still quite good.

The brewing is also controlled by the Arduino. They plan to add voice control so that they can simply ask, “Alexa, make me coffee”, but for now they added a switch on the side to start the brewing. That switch tells the Arduino to work one servo to open the cover, another to insert a coffee filter, and two more to scoop up some coffee from a container and dump it into the filter.

They replaced the coffee maker’s on/off switch with a relay so that after the Arduino closes the cover again, it uses the relay to start the brewing. The result is surprisingly human-like. We especially like the graceful movement achieved by the two servos for scooping up and dumping the coffee. Full disclosure: they did admit that it would often either not scoop enough coffee or scoop enough but spill a bunch on the group.

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Pick-And-Place Machine For Candy

December 29, 2016 by Bryan Cockfield No comments

Every December and May the senior design projects from engineering schools start to roll in. Since the students aren’t yet encumbered with real-world detractors (like management) the projects are often exceptional, unique, and solve problems we never even thought we had. Such is the case with [Mark] and [Peter]’s senior design project: a pick and place machine that promises to solve all of life’s problems.

Of course we’ve seen pick-and-place machines before, but this one is different. Rather than identifying resistors and capacitors to set on a PCB, this machine is able to identify and sort candies. The robot — a version of the MeARM — has three degrees of freedom and a computer vision system to alert the arm as to what it’s picking up and where it should place it. A Raspberry Pi handles the computer vision and feeds data to a PIC32 which interfaces with the hardware.

One of the requirements for the senior design class was to keep the budget under $100, which they were able to accomplish using pre-built solutions wherever possible. Robot arms with dependable precision can’t even come close to that price restraint. But this project overcomes the lack of precision in the MeArm by using incremental correcting steps to reach proper alignment. This is covered in the video demo below.

Senior design classes are a great way to teach students how to integrate all of their knowledge into a final class, and the professors often include limits they might find in the real world (like the budget limit in this project). The requirement to thoroughly document the build process is also a lesson that more people could stand to learn. Senior design classes have attempted to solve a lot of life’s other problems, too; from autonomous vehicles to bartenders, there’s been a solution for almost every problem.

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Improving Raspberry Pi Disk Performance

December 29, 2016 by Al Williams 31 Comments

Usually, you think of solid state storage as faster than a rotating hard drive. However, in the case of the Raspberry Pi, the solid state “disk drive” is a memory card that uses a serial interface. So while a 7200 RPM SATA drive might get speeds in excess of 100MB/s, the Pi’s performance is significantly less.

[Rusher] uses the Gluster distributed file system and Docker on his Raspberry Pi. He measured write performance to be a sluggish 1MB/s (and the root file system was clocking in at just over 40MB/s).

There are an endless number of settings you could tweak, but [Rusher] heuristically picked a few he thought would have an impact. After some experimentation, he managed 5MB/s on Gluster and increased the normal file system to 46 MB/s.

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