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Hackaday Links: September 24, 2017

This is it. After twelve years we finally have a new Star Trek. Star Trek: Discovery (we’re using ST:DSC as the abbreviation) is airing right about when this post goes up. Next week, you’ll have to pay CBS $6USD a month to get your Star Trek fix, and today might be the last time a new episode of Star Trek is aired on broadcast TV ever. Enjoy it now, and hope the theme song doesn’t have lyrics. Also, hope The Orville is a tenth as good as a Galaxy Quest series could be.

What’s the best way to describe Delta Sigma PLLs? The Cat In The Hat (PDF, page 31). [Dr. Tune] found a Seuss reference in a TI app note. Personally, I’m a fan of hand-drawn cartoons, but we’ll take what we can get.

This weekend the Prusa I3 MK3 was announced. A good printer just got better. Now here’s the video.

The Raspberry Pi is a great media storage device, but it’s absolutely insufficient for audiophile tomfoolery. Here’s a neat Pi DAC/amp/DSP thingy. The VoltaStream turns the Raspberry Pi into a WiFi-connected pair of speakers with low-latency audio in and a TOSLINK connector.

SpaceX! There is serious consideration being given to starting an ‘Elon Musk column’ here on Hackaday. There will be SpaceX updates coming this week from the International Astronautical Congress in Adelaide. What will we find out? I don’t know bruh, but I just got back from Burning Man and I realized it was a whole lot like Mars and I was wondering Elon, like, have you ever been to Burning Man because it’s really dusty and a whole lot like Mars and there’s not much water… Please, organizers of the IAC, I implore you: give more idiots microphones. That was hilarious.

How was the World Maker Faire in New York this weekend? In one word, empty. Abnormally so. Maker Faire was not as crowded as last year, and you could actually move around. My agoraphobia didn’t kick in until the afterparties, and lines for the $5 bottles of water were short. Bay Area Faire attendance was down 16% from 2016-2017, and I would bet attendance for the NY Faire would be down a similar amount. Even a 10% decline in attendance would be noteworthy; the weather last year was cold and rainy and this year was beautiful. There are rumors, speculation, and people wondering how long Maker Faire will continue, but except for Intel pulling out of the maker market, no actual information. Millennials are killing the Maker Faire industry?

8-Channel ADC For The Raspberry Pi

The Raspberry Pi is a powerful embedded computing platform. However, for all its Linux-based muscle, it lacks one thing that even the simplest 8-bit microcontrollers usually have – analog-to-digital conversion. There are a great many ways to rectify this shortcoming, and [Chris Burgess] has brought us another – with an 8-channel ADC for the Raspberry Pi.

For the ADC, [Chris] chose the MCP3008, for its low cost and availability. In this configuration it offers 10-bit resolution and a maximum sampling rate of 200 kilosamples per second. Adafruit has a great guide on working with the MCP3008, too. With such a useful resource to hand, [Chris] was able to spin up a PCB to interface the chip to the Raspberry Pi using SPI. [Chris] took care to try to make the board to the official HAT specifications. As far as the physical aspects go, the board is to spec, however [Chris] omitted the EEPROM required for auto-configuration purposes. That said, the pads are on the board if someone wants to take the initiative to install one.

It’s a tidy build that provides something sorely missing from the Raspberry Pi, for a reasonable cost. [Chris]’s goal was to build something that would enable the measurement of analog sensors for a robot project; we’d love to hear your ideas for potential uses in the comments!

Arduino And Pi Breathe New Life Into Jukebox

What do you do when someone gives you a Wurlitzer 3100 jukebox from 1969, but keeps all the records? If you are like [Tijuana Rick], you grab an Arduino and a Rasberry Pi and turn it into a really awesome digital music player.

We’ll grant you, making a music player out of a Raspberry Pi isn’t all that cutting edge, but restoration and integration work is really impressive. The machine had many broken switches that had been hastily repaired, so [Rick] had to learn to create silicone molds and cast resin to create replacements. You can see and hear the end result in the video below.

[Rick] was frustrated with jukebox software he could find, until he found some Python code from [Thomas Sprinkmeier]. [Rick] used that code as a base and customized it for his needs.

There’s not much “how to” detail about the castings for the switches, but there are lots of photos and the results were great. We wondered if he considered putting fake 45s in the machine so it at least looked like it was playing vinyl.

Of course, you don’t need an old piece of hardware to make a jukebox. Or, you can compromise and build out a replica.

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Hackaday Prize Entry: The $50 Raspberry Pi Smartphone

The Hackaday Prize is a challenge to create hardware, and the ZeroPhone is quite possibly the most popular project entered in the Hackaday Prize. What is it? It’s a mobile phone built around the Raspberry Pi Zero that can be assembled for about $50 in parts. Already, it’s a finalist in the Hackaday Prize best product competition, a finalist for the grand prize of $50,000, and one of the most popular projects on Hackaday.io of all time.

We took a look at the ZeroPhone early this year, and while there have been significant advances in this project, the philosophy is still pretty much the same. This is a mobile phone with a numeric keypad and a 128 x 64 pixel OLED display — basically the same user interface as a Nokia brick. The brain of the phone is a Raspberry Pi Zero wrapped in a PCB sandwich, with options for WiFi, Bluetooth, HDMI and audio outputs, a USB port, battery charging, and a ton of GPIOs that include ISM band radios, infrared receivers and transmitters, more flash storage, and anything else you can imagine. Basically, we’re looking at one of those modular, reconfigurable smartphone ideas, using a Raspberry Pi as the brains. Tech journos should be creaming themselves over this. We’re looking forward to [Arsenijs]’ cover story in Wired.

As with any Open Source / DIY cell phone, the big question surrounding the ZeroPhone is the cellular radio. 2G radios are cheap and plentiful, but the infrastructure is either coming down shortly, or already is down. A 3G radio is a must for a minimum viable product, and [Arsenijs] says there are provisions for replacing the 2G radio with a 3G module. Of course, 3G modules aren’t as capital-‘O’-Open as their technological predecessors, but that’s a discussion for another time.

Already the ZeroPhone is a huge success. There’s an actual team working on this project, the ZeroPhone subreddit is bigger than the Hackaday subreddit, there are newsletters, a wiki, and there will be a crowdfunding campaign ‘shortly’. This is one to look out for, and a very worthy project in the running for the 2017 Hackaday Prize.

Table-Top Self Driving With The Pi Zero

Self-driving technologies are a hot button topic right now, as major companies scramble to be the first to market with more capable autonomous vehicles. There’s a high barrier to entry at the top of the game, but that doesn’t mean you can’t tinker at home. [Richard Crowder] has been building a self-driving car at home with the Raspberry Pi Zero.

The self-driving model is trained by first learning from the human driver.

[Richard]’s project is based on the EOgma Neo machine learning library. Using a type of machine learning known as Sparse Predictive Hierarchies, or SPH, the algorithm is first trained with user input. [Richard] trained the model by driving it around a small track. The algorithm takes into account the steering and throttle inputs from the human driver and also monitors the feed from the Raspberry Pi camera. After training the model for a few laps, the car is then ready to drive itself.

Fundamentally, this is working on a much simpler level than a full-sized self-driving car. As the video indicates, the steering angle is predicted based on the grayscale pixel data from the camera feed. The track is very simple and the contrast of the walls to the driving surface makes it easier for the machine learning algorithm to figure out where it should be going. Watching the video feed reminds us of simple line-following robots of years past; this project achieves a similar effect in a completely different way. As it stands, it’s a great learning project on how to work with machine learning systems.

[Richard]’s write-up includes instructions on how to replicate the build, which is great if you’re just starting out with machine learning projects. What’s impressive is that this build achieves what it does with only the horsepower of the minute Raspberry Pi Zero, and putting it all in a package of just 102 grams. We’ve seen similar builds before that rely on much more horsepower – in processing and propulsion.

Hackaday Prize Entry: Dementia-Friendly Music Player

The loss of memory is an extremely difficult situation, not just for those afflicted, but also for immediate family, close friends, and care givers. With no cure available for dementia, providing care is an extremely demanding task for everyone involved – both mentally and physically. Patients are unable to retain recent events and information, but will most likely be able to recall some amount of past memories. This presents serious challenges when they encounter “modern” technology and cannot figure out how to use and operate everyday devices that normal people take for granted.

[rosswesleyporter]’s Dad had trouble using modern iPods and CD players, so he built DQMusicBox — a Dementia friendly music player. It’s very simple interface resembling a radio from half a century ago. There are just two large, clearly marked rotary dials — one for Volume, the other for Songs, and a headphone socket. The inspiration came from a very moving documentary called “Alive Inside” which explores how music brings extreme joy to people with dementia.

The device is built around a Raspberry Pi, enclosed in a laser cut enclosure and requires no soldering — making it easy for anyone to build one for themselves using easily available parts. The Raspberry Pi runs on a lightweight, optimized version of Raspbian called DietPi. The music playback is handled by VLC ensuring support for a large number of music formats. A Python script looks for music files, sets up the VLC-NOX player and handles knob and button events. A bundled image file for the software includes everything needed to get it running, making setup easy and quick. Since Raspberry Pi’s are prone to OS corruption when power is disconnected without performing a proper shutdown, [Ross] uses write protection on the SD-card and walks you through the process of how it works.

Between his Project page, Github and DQMusicBox website, you will be able to get all the information needed to replicate this excellent project. And for his next version, he already has a few ideas for improvement and would like to hear if other hackers have suggestions.

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The World’s Thinnest Raspberry Pi 3

We’ve become used to readily available single board computers of significant power in form factors that would have seemed impossibly small only a few years ago. But even with a board the size of a credit card such as a Raspberry Pi, there are still moments when the available space is just too small to fit the computer.

The solution resorted to by enterprising hardware hackers is often to remove extraneous components from the board. If there is no need for a full-size USB port or an Ethernet jack, for example, they can safely be taken away. And since sometimes these attempts result in the unintended destruction of the board, yonder pirates at Pimoroni have taken viewers of their Bilge Tank series of videos through the procedure, creating in the process what they describe as “The World’s Thinnest Raspberry Pi 3“.

The USB and Ethernet ports, as large through-hole components, were the easiest to tackle. Some snipping and snapping removed the tinware and plastic, then the remains could be hand-desoldered. The GPIO pins resisted attempts to remove their plastic for easy desoldering, so for them they had to resort to a hot air gun. Then for the remaining camera, HDMI, and display ports the only option was hot air. Some cleaning up with desoldering braid, and they had their super-thin Pi. They weren’t quite done though, they then took the reader through modifying a Raspbian Lite distribution to deactivate support those components that have been removed. This has the handy effect not only of freeing up computer resources, it also saves some power consumption.

You might point out that they could have just used a Pi Zero, which with its SD card on the top surface is even a little bit thinner. And aside from the question of extra computing power, you’d be right. But their point is valid, that people are doing this and not always achieving a good result, so their presenting it as a HOWTO is a useful contribution. We suspect that a super-thin Pi 3 will still require attention to heat management though.

Take a look at the video, we’ve put it below the break.

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