A $5 Graphics Card For Homebrew Computers

March 14, 2016 by Brian Benchoff 39 Comments

While not very popular, building a homebrew computer can be a fun and rewarding process. Most of the time, though, the video capabilities of these computers is as bare bones as it can get – running headless, connected to a terminal. While this is an accurate reproduction of the homebrew computers of the 1970s and 80s, there’s a lot to be said about a DIY computer with an HDMI-out port.

[spencer] built a Z-80-based homebrew computer a few years ago, and while connecting it to a terminal was sufficient, it was a build that could use a little more pizzazz. How did he manage to stuff a terminal in a tiny project box? With everyone’s favorite five dollar computer, the Raspberry Pi Zero.

The computer [spencer] built already had serial inputs, outputs, power, and ground rails – basically, a serial port. The Raspberry Pi also has TX and RX pins available on the 40-pin header, and with a stupidly simple board that [spencer] whipped up in KiCad, he could plug a Pi into the backplane of his homebrew computer. A few setup scripts, and a few seconds after turning this computer on [spencer] could mash a keyboard and wail away on some old school BASIC.

This isn’t a use case that is the sole domain of the Pi Zero. A Parallax Propeller chip makes for a great video terminal with inputs for PS/2 keyboards and mice. A largish AVR, with the requisite NTSC video library, also makes for a great video interface for a homebrew computer. The Pi Zero is only five dollars, though.

The Raspberry Pi Zero contest is presented by Hackaday and Adafruit. Prizes include Raspberry Pi Zeros from Adafruit and gift cards to The Hackaday Store!
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A Pi Powered Recording Studio

March 13, 2016 by Brian Benchoff 48 Comments

In the mid-90s, you recorded your band’s demo on a Tascam cassette tape deck. These surprisingly cheap four-track portable studios were just low tech enough to lend an air of authenticity to a band that calls itself, ‘something like Pearl Jam, but with a piano’. These tape decks disappeared a decade later, just like your dreams of being a rock star, replaced with portable digital recording studios.

The Raspberry Pi exists, the Linux audio stack is in much better shape than it was ten years ago, and now it’s possible to build your own standalone recording studio. That’s exactly what [Daniel] is doing for our Raspberry Pi Zero contest, and somewhat predictably he’s calling it the piStudio.

Although the technology has moved from cassette tapes to CompactFlash cards to hard drives, the design of these four-track mini recording studios hasn’t really changed since their introduction in the 1980s. There are four channels, each with a fader, balance, EQ, and a line in and XLR jack. There are master controls, a few VU meters, and if the technology is digital, a pair of MIDI jacks. Since [Daniel] is using a Raspberry Pi for this project, he threw in an LCD for a great user interface.

As with all digital recorders, the money is in the analog to digital converters. [Daniel] is using a 24-bit, 216kHz, four-channel chip, Texas Instruments’ PCM4204. That’s more than enough to confuse the ears of an audiophile, although that much data will require a hard drive. Good thing there will be SATA.

Although you can buy an eight-channel solid state recorder for a few hundred dollars – and [Daniel] will assuredly put more than that into this project, it’s a great application of a ubiquitous Linux computer for a device that’s very, very useful.

The Raspberry Pi Zero contest is presented by Hackaday and Adafruit. Prizes include Raspberry Pi Zeros from Adafruit and gift cards to The Hackaday Store!
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One Man’s Quest To Spend Less TIme In The Basement

March 12, 2016 by Brian Benchoff 45 Comments

[Lars] has a second floor apartment, and the washing machines and clothes dryers are in the basement. This means [Lars] has spent too much time walking down to the basement to collect his laundry, only to find out there is 15 minutes left in on the cycle. There are a few solutions to this: leave your load in the washer like an inconsiderate animal, buy a new, fancy washer and dryer with proprietary Internet of Things™ software, or hack together a washer and dryer monitoring solution. We all know what option [Lars] chose.

Connecting a Pi to the Internet and serving up a few bits of data is a solved problem. The hard part is deciding which bits to serve. Washers and dryers all have a few things in common: they both use power, they both move and shake, they make noise, and their interfaces change during the wash cycle. [Lars] wanted a device that could be used with washers and dryers, and could be used with other machines in the future. He first experimented with a microphone, capturing the low rumble of a washer sloshing about and a dryer tumbling a load of laundry. It turns out an accelerometer works just as well, and with a sensor securely fastened to a washer or dryer, [Lars] can get a pretty good idea if it’s running or not.

With a reliable way to tell if a washer or dryer is still running, [Lars] only had to put this information on his smartphone. He ended up using PushBullet, and quickly had an app on his phone that told him if his laundry was done.

Raspberry Pi Zero Round 1 Winners!

March 1, 2016 by Adam Fabio 27 Comments

The Raspberry Pi Zero Contest presented by Adafruit and Hackaday has been going incredibly well! We currently have 132 projects entered, and there is still time for YOU to get in on the fun! The only problem entrants have had is getting their hands on these amazing $5 computers. We’ve made that easy by giving away ten Raspberry Pi Zero boards. The following projects were well documented, well thought out projects were selected by the judges. We’ve already informed the winners through Hackaday.io, and will be shipping out the Pi Zero boards to them right away.

[Ajlitt] with RPi WiFi
[Die, Master Monkey!] with IQ Zero: Evolving Stupid, Imperfect Robots
[spencer] with $5 Graphics Card For Homebrew Z80
[JohSchneider] with PiGrrl-Zero
[Patrick Van Oosterwijck] with LiFePO4wered/Pi
[Erland Lewin] with Pi Chart
[Lars Knudsen] with Monitoring washing machines
[Daniel Frausto] with piStudio
[Markus Dieterle] with TextEye: Raspberry Pi (Zero) Mobile Textreader
[Brook Patten] with Mr. Gibbs

Please join the judges and the entire Hackaday staff in congratulating the winners of the Pi Zero boards!

If you didn’t win, all is not lost! There is still time to enter the contest. The deadline is 11:59 pm PST on March 13, 2016. You’ll be in the running for one of three $100 gift certificates to The Hackaday Store!

Giving The Pi Zero USB, Ethernet, And Serial Over USB

February 25, 2016 by Brian Benchoff 55 Comments

Just as the USB port on your phone can serve as a serial connection, mass storage device, and a network connection, the Pi Zero can do the same. We’ve seen a few people turn the Zero into a single USB gadget, but what about turning the Zero into a USB HID device, network connection, and serial port all at the same time? That’s what [Tobias] did, and his method is even easier than the old one.

The old method of turning the Pi Zero into a USB device required the user to modify and recompile the kernel. Obviously, this isn’t an ideal solution. [Tobias]’ implementation fixes this by putting everything into userland. Everything is configurable through a script and a few tweaks to how the Pi starts up.

The result is a Raspberry Pi Zero that will appear as any USB peripheral. [Tobias] goes through the usual examples: setting the Pi up as a serial device for hacking and code cracking in a terminal, as an Ethernet device to give the Pi Zero networking capabilities, as a keyboard to send keypresses to another computer, and as a mass storage device so that other computers can read a small portion of the Pi’s SD card.

There are plenty more USB gadgets the Pi can emulate, from printers to audio devices to MIDI adapters to webcams. If you can wrap your head around what a Pi Zero could do when configured as one of these devices, drop a note in the comments.

Hacklet 96 – Pi Zero Contest Projects Week 3

February 20, 2016 by Adam Fabio 3 Comments

The calendar is rolling through the third week of the house that Hackaday and Adafruit built: The Raspberry Pi Zero Contest. We’re nearly at 100 entries! Each project is competing for one of 10 Raspberry Pi Zeros, and one of three $100 gift certificates to The Hackaday Store. This week on The Hacklet, we’re going to take a look at a few more contest entries.

[Phil “RzR” Coval] is trying to Port Tizen to the Raspberry Pi Zero. For those not in the know, Tizen is an open source operating system for everything. Billed as a go-to OS for everything from wearables to tablets to smartphones to in-vehicle entertainment systems, Tizen is managed by the Linux Foundation and a the Tizen Association. While Tizen works on a lot of devices, the Raspberry Pi and Pi 2 are still considered “works in progress”. Folks are having trouble just getting a pre-built binary to run. [Phil] is taking the source and porting it to the limited Pi Zero platform. So far he’s gotten the Yocto-based build to run, and the system starts to boot. Unfortunately, the Pi crashes before the boot is complete. We’re hoping [Phil] keeps at it and gets Tizen up and running on the Pi Zero!

Next up is [shlonkin] with Classroom music teaching aid. Guitar Hero has taught a generation of kids to translate flashing lights to playing notes on toy instruments. [Shlonkin] is using similar ideas to teach students how to play real music on a harmonica. The Pi Zero will control a large display model of a harmonica at the front of the classroom. Each hole will light up when that note is to be played. Harmonica’s have two notes per hole. [Shlonkin] worked around this with color. Red LEDs mean blow (exhale), and Blue LEDs mean draw (inhale). The Pi Zero can do plenty more than blink LEDs and play music, so [shlonkin] plans to have the board analyze the notes played by the students. With a bit of software magic, this teaching tool can provide real-time feedback as the students play.

[Spencer] is putting the Pi Zero to work as a $5 Graphics Card For Homebrew Z80. The Z80 in this case is RC2014, his DIY retro computer. RC2014 was built as part of the 2014 RetroChallenge. While the computer works, it only has an RS-232 serial port for communication to the outside world. Unless you have a PC running terminal software nearby, the RC2014 isn’t very useful. [Spencer] is fixing that by using the Pi Zero as a front end for his retro battle station. The Pi handles USB keyboard input, translates to serial for the RC2014, and then displays the output via HDMI or the composite video connection. The final design fits into the RC2014 backplane through a custom PCB [Spencer] created with a little help from kicad and OSHPark.

Finally we have [txdo.msk] with 8 Leaf Pi Zero Bramble. At $5 each, people are scrambling to build massively parallel supercomputers using the Raspberry Pi Zero. Sure, these aren’t practical machines, but they are a great way to learn parallel computing fundamentals. It only takes a couple of connectors to get the Pi Zero up and running. However, 8 interconnected boards quickly makes for a messy desk. [Txdo.msk] is designing a 3D printed modular case to hold each of the leaves. The leaves slip into a bramble box which keeps everything from shorting out. [Txdo.msk] has gone through several iterations already. We hope he has enough PLA stocked up to print his final design!

If you want to see more entrants to Hackaday and Adafruit’s Pi Zero contest, check out the submissions list! If you don’t see your project on that list, you don’t have to contact me, just submit it to the Pi Zero Contest! That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

A Quadcopter Controlled By A Pi Zero

February 16, 2016 by Brian Benchoff 57 Comments

Flight controllers for quadcopters and other drones are incredible pieces of engineering. Not only do these boards keep an aircraft level, they do so while keeping the drone in one place, or reading a GPS sensor and flying it from waypoint to waypoint. The latest of these flight controllers is built on everyone’s favorite $5 computer, the Raspberry Pi Zero.

The PXFmini controller and autopilot shield is the latest project from Erle Robotics that puts eight servo outputs on the Pi, barometer and IMU sensors, a power supply, and all the adapters to turn the Raspberry Pi Zero into a capable flight controller. Since the Pi Zero will have some computational horsepower left over after keeping a quadcopter level, there’s a possibility of some very cool peripherals. Erle Robotics has been working with depth cameras and Lidar on more than a few drones. This makes for some interesting applications we can only imagine now.

The schematics for the PXFmini are open source in the best traditions of the RC and drone community and will be available soon. You can check out a video of the FXPmini flying around an office below.

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