Raspberry Pi

1848 Articles

Need A Tiny CRT? Karaoke Might Just Help

July 31, 2018 by 30 Comments

[Brett] is working on a video installation, and for the past few months, has been trying to get his hands on tiny CRTs any way he can. After initially coming up short, he happened across a karaoke machine from 2005, and got down to work.

Karaoke machines of this vintage are typically fairly low-rent affairs, built cheaply on simple PCBs. [Brett] found that the unit in question was easy to disassemble, having various modules on separate PCBs joined together with ribbon cables and headers. However, such machines rarely have video inputs, as they’re really only designed to display low-res graphics from CD-G format discs.

While investigating the machine, initial research online proved fruitless. In the end, a close look at the board revealed just what [Brett] was looking for – a pin labeled video in! After throwing in a Raspberry Pi Zero and soldering up the composite output to the karaoke machine’s input pin, the screen sprung to life first time! This initial success was followed by installing a Raspberry Pi 3 for more grunt, combined with a Screenly install – and a TRS adapter the likes of which we’ve never seen before. This allows video to be easily pushed to the device remotely over WiFi. [Brett] promises us there is more to come.

Karaoke is a sparse topic in the Hackaday archives, but we’ve seen a couple builds, like this vocal processor. If you’ve got the hacks, though? You know where to send ’em.

GTA: San Andreas Radio Earns Six-Star Wanted Level

July 25, 2018 by 14 Comments

[Raphaël Yancey] wanted to be able to jam to Bounce FM and Radio:X all the time, without having to steal a car or a street sweeper in San Andreas. As people who like to put on the sad piano building music from The Sims and write Hackaday posts, we can totally relate.

But this isn’t just another one of those jam-a-Pi-into-a-vintage-radio-and-call-it-a-sandwich projects (not that there’s anything wrong with those). This thing acts like a real radio. All the stations play continuously whether you’re tuned in or not, and they bleed into each other as you go up and down the dial.

After much trial and error, [Raphaël] found a Python mixer that would work, but it was no longer maintained. He forked it, squashed a bug or two, and wrote a module for KY040 rotary encoders to make them play nice with the Pi. The snake charming doesn’t stop there: the rock star of this project is [Raphaël]’s virtual radio software, which handles the audio blending as he tunes between stations. A step-by-step tutorial is coming soon, so watch [Raphaël]’s site for updates. Tune past the break to give it a listen.

Adventures in Raspi radio-ing don’t have to be one-way. Here’s how you can turn one into an AM/FM+ transmitter using a DVB-T dongle and SDR.

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Behind The Pin: How The Raspberry Pi Gets Its Audio

July 13, 2018 by 54 Comments

Single board computers have provided us with a revolution in the way we approach computing as hardware creators. We have grown accustomed to a world in which an entire microcomputer has become a component in its own right rather than a complex system, and we interface to them as amorphous entities through their exposed interfaces. But every pin or socket on a single board computer has something behind it, so following up on a recent news-inspired item in which we took a look at what lies behind the Ethernet jack on a Raspberry Pi, we’d like to continue that theme by looking behind more pins and interfaces. So today we’ll stay with the Raspberry Pi, and start with an easy target by taking a look down its audio jack.

All the main Raspberry Pi board releases since 2012 with the exception of the Pi Zero series, have featured a 3.5mm jack carrying line-level audio. The circuits are readily accessible via the Raspberry Pi website, and are easy enough to understand because of course all the really hard work is done within the silicon of the Broadcom system-on-chip. Looking at the audio circuitry, we’ll start by going back to the original Pi Model B from 2012 (PDF) because though more recent models have seen a few changes, this holds the essence of the circuitry.

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Old Time Traffic Signal Revived With A Raspberry Pi Controller

July 12, 2018 by 28 Comments

Anyone with even a passing familiarity with the classic animated shorts of the 1940s will recognize the traffic signal in the image above. Yes, such things actually existed in the real world, not just in the Looney world of [Bugs Bunny] et al. As sturdy as such devices were, they don’t last forever, though, which is why a restoration of this classic Acme traffic signal was necessary for a California museum. Yes, that Acme.

When you see a traffic signal from the early days of the automotive age like this one, it becomes quickly apparent how good the modern equivalent has become. Back in the day, with a mix of lights distributed all over the body of the signal, arms that extend out, and bells that ring when the state changes, it’s easy to see how things could get out of hand at an intersection. That complexity made the restoration project by [am1034481] and colleagues at the Southern California Traffic Museum all the more difficult. Each signal has three lights, a motor for the flag, and an annunciator bell, each requiring a relay. What’s more, the motor needs to run in both directions, so a reversing relay is needed, and the arm has a mechanism to keep it in position when motor power is removed, which needs yet another relay. With two signals, everything was doubled, so the new controller used a 16-channel relay board and a Raspberry Pi to run through various demos. To keep induced currents from wreaking havoc, zero-crossing solid state relays were used on the big AC motors and coils in the signal. It looks like a lot of work, but the end results are worth it.

Looking for more information on traffic signal controls? We talked about that a while back.

Smart Power Strip Revived With Raspberry Pi

July 6, 2018 by 19 Comments

We’re all for buying broken stuff from eBay to save yourself a few bucks: buy it cheap, fix it, and reap the rewards of being a step ahead of the average consumer. Searching through the “For parts or not working” categories is nearly the official pastime here at the Hackaday Bunker. But buying an eBay find only to have it give up the ghost in a couple weeks? That hurts.

That’s precisely what happened to [idaresiwins] when he bought this beefy looking “Web Power Switch” on the Electronic Bay. After two weeks, the controller board blew and his “smart” power strip became very stupid indeed. But with the addition of a Raspberry Pi, he’s got it back up and running. Not only that, but given the extra horsepower this device now contains, it now doubles as a basic server for the home lab.

This conversion was helped by the fact that the original controller was on a separate board from the relays, and connected with a small ribbon cable. All [idaresiwins] had to do was figure out which wire in the cable went to each of the eight relays, and fire them off with the Pi’s GPIO pins. In an interesting detail, he opened up one of the ends of the ribbon cable and used it as a punch down block of sorts to easily hook the wires up to the Pi’s pins. We might suggest some hot glue to keep everything from moving around, but otherwise it’s a neat tip.

[idaresiwins] found some information online about making a web-based GPIO interface, which he adapted to control the outlets on the power strip. He then wrapped the Pi up in plastic to keep it from shorting out, and tucked it inside the case. Note that he was able to pull 5 VDC from the relay board and run it to the Pi over the ribbon cable, so he didn’t need to bother with hacking a USB adapter in there.

Controlling AC devices over the Interwebs is an extremely popular project, and we’ve even seen a DIY device that looks quite similar to this product. Most of them are now using the ESP8266, but with the Pi onboard this hack is more like a super-sized version of the PowerPwn.

Solar Pi Cluster Scours Internet For Nudes

July 6, 2018 by 50 Comments

There seems to be a universal truth on the Internet: if you open up a service to the world, eventually somebody will come in and try to mess it up. If you have a comment section, trolls will come in and fill it with pedantic complaints (so we’ve heard anyway, naturally we have no experience with such matters). If you have a service where people can upload files, then it’s a guarantee that something unsavory is eventually going to take up residence on your server.

Unfortunately, that’s exactly what [Christian Haschek] found while developing his open source image hosting platform, PictShare. He was alerted to some unsavory pictures on PictShare, and after he dealt with them he realized these could be the proverbial tip of the iceberg. But there were far too many pictures on the system to check manually. He decided to build a system that could search for NSFW images using a trained neural network.

The nude-sniffing cluster is made up of a trio of Raspberry Pi computers, each with its own Movidius neural compute stick to perform the heavy lifting. [Christian] explains how he installed the compute stick SDK and Yahoo’s open source learning module for identifying questionable images, the aptly named open_nsfw. The system can be scaled up by adding more Pis to the system, and since it’s all ARM processors and compute sticks, it’s energy efficient enough the whole system can run off a 10 watt solar panel.

After opening up the system with a public web interface where users can scan their own images, he offered his system’s services to a large image hosting provider to see what it would find. Shockingly, the system was able to find over 3,000 images that contained suspected child pornography. The appropriate authorities were notified, and [Christian] encourages anyone else looking to search their servers for this kind of content to drop him a line. Truly hacking for good.

This isn’t the first time we’ve seen Intel’s Movidius compute stick in the wild., and of course we’ve seen our fair share of Raspberry Pi clusters. From 750 node monsters down to builds which are far more show than go.

Shooting For The First Time With Help From A Raspberry Pi

July 5, 2018 by 15 Comments

Like many people, [Mike] has a list of things he wants to do in life. One of them is “fire a gun with a switch,” and with a little help from some hacker friends, he knocked this item off last weekend.

For those wondering why the specificity of the item, the backstory will help explain. [Mike] has spinal muscular atrophy, a disease that was supposed to end his life shortly after it began. Thirty-seven years later, [Mike] is still ticking items off his list, but since he only has voluntary control of his right eyebrow, he faces challenges getting some of them done. Enter [Bill] and the crew at ATMakers. The “AT” stands for “assistive technologies,” and [Bill] took on the task of building a rig to safely fire a Glock 17 upon [Mike]’s command.

Before even beginning the project, [Bill] did his due diligence, going so far as to consult the Bureau of Alcohol, Tobacco, and Firearms (ATF) and arranging for private time at a local indoor gun range. The business end of the rig is a commercially available bench rest designed to control recoil from the pistol, which is fired by a servo connected to the trigger. The interface with [Mike]’s system is via a Raspberry Pi and a Crikit linked together by a custom PCB. A PiCam allowed [Mike] to look down the sights and fire the gun with his eyebrow. The videos below show the development process and the day at the range; to say that [Mike] was pleased is an understatement.

We’re not sure what else is on [Mike]’s list, but we see a lot of assistive tech projects around here — we even had a whole category of the 2017 Hackaday Prize devoted to them. Maybe there’s something else the Hackaday community can help him check off.

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