Sweet Stepper of [Jeremy]‘s Rocks Out with its Box Out

Stepper motor MIDI music boxInspired by the floppy drive orchestras of others, [Jeremy] has built a Pi-driven MIDI music box with stepper motor resonators and outlined the build on hackaday.io.

Control for the motors comes from an Iteaduino Mega 2560. The music starts as a MIDI file, gets processed into a text file, and is played over serial by a Raspberry Pi. He’s added percussion using K’NEX instruments and 9g servos, which we think is a nice touch. It can be powered via LiPo or from the wall, and [Jeremy] baked in protection against blowing up the battery. As he explains in the tour video after the break, the box is clamped to a wooden table to provide richer sound.

[Jeremy]‘s favorite part of the build was enclosing the thing as it was his first time using panel-mount components. Stick around to see a walk-through of the guts and a second video demonstrating its musical prowess.

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LEDs Turn This Paper Map into a Tram Tracker

Subway radar

Public transit can be a wonderful thing. It can also be annoying if the trains are running behind schedule. These days, many public transit systems are connected to the Internet. This means you can check if your train will be on time at any moment using a computer or smart phone. [Christoph] wanted to take this concept one step further for the Devlol hackerspace is Linz, Austria, so he built himself an electronic tracking system (Google translate).

[Christoph] started with a printed paper map of the train system. This was placed inside what began as an ordinary picture frame. Then, [Christoph] strung together a series of BulletPixel2 LEDs in parallel. The BulletPixel2 LEDs are 8mm tri-color LEDs that also contain a small controller chip. This allows them to be controlled serially using just one wire. It’s similar to having an RGB LED strip, minus the actual strip. [Christoph] used 50 LEDs when all was said and done. The LEDs were mounted into the photo frame along the three main train lines; red, green, and blue. The color of the LED obviously corresponds to the color of the train line.

The train location data is pulled from the Internet using a Raspberry Pi. The information must be pulled constantly in order to keep the map accurate and up to date. The Raspberry Pi then communicates with an Arduino Uno, which is used to actually control the string of LEDs. The electronics can all be hidden behind the photo frame, out of sight. The final product is a slick “radar” for the local train system.

Raspberry Pi Gets VGA, Dual Screen Support


The Broadcom SOC in the Raspberry Pi is actually surprisingly powerful, it turns out. It’s actually capable of driving a VGA monitor through the GPIO pins using a handful of resistors.

[Gert van Loo], Raspberry Pi chip architect, wizard, and creator of a number of interesting expansion boards showed off a VGA adapter for the new B+ model at the recent Raspberry Pi Jam in Cambridge this week. Apparently, there is a parallel interface on the SoC that can be used to drive VGA with hardware using a resistor ladder DAC. That’s native VGA at 1080p at 60 fps in addition to HDMI for the Raspberry Pi. Only the new Model B+ has enough pins to do this, but it’s an intriguing little board.

The prospect of having two displays for a Raspberry Pi is very interesting, and the remaining four GPIOs available mean a touch screen could be added to one display, effectively making a gigantic Nintendo DS. Of course there are more practical problems a dual display Raspi solves, like driving a projector for the current crop of DSP/resin 3D printers, while still allowing for a usable interface during a print.

The VGA expansion board, “is likely to have issues with EMC,” which means this probably won’t be a product. Getting a PCB made and soldering SMD resistors isn’t that hard, though, and we’ll post an update when the board files are released.

Thanks [Uhrheber] for sending this one in.

HackerSpace Monitor Monitors Hackerspace Environment

Hackerspace Monitor

What’s going on at the Hackerspace? If you can’t answer that, maybe your ‘space needs a HackerSpace Monitor. [Tayken] over at the Tokyo Hackerspace has come up with a way to remotely monitor all the stuff you’d want to know about the ‘space.

His project is based on a Raspberry Pi with a webcam connected to the Pi’s USB port by way of a hub. The webcam is set up to stream 2 frames per second, which is plenty to be able to judge the activity at the ‘space. A WiFi dongle is also plugged into the USB hub in order to gain internet access, send out the video and allow the ability to SSH into the Pi.

What if you’re on the fence about heading over to work on your favorite project but the current weather leaves you wondering what the temperature is going to be like at the hackerspace? Well, this project has that covered too. An off the shelf temperature and humidity sensor plugs directly into the Pi’s GPIO pins. [Tayken] used the Python-based package, RPi.GPIO, to manage the temperature and humidity sensor readings as well as a toggle switch that monitors if the main door is open or closed.

To get everything all the above information to be displayed on a webpage, [Tayken] had to do some fancy programming. Luckily for us, he has made all his code available for download. Not only is this a great convenience for members, but it can also show non-members when it is or isn’t a good time to show up to check the ‘space out.

Adding I/O to the Rasberry Pi Models A & B

PiMagic RaspPi to Arduino Shield Interface

The Raspberry Pi has been the basis for many cool projects. Even so, Models A and B have been criticized for having only a handful of GPIO pins available. Sure, the new Model B+ has a 40-pin GPIO header but what if you want to use your old RaspPi with a bunch of in and outputs? [Steve] is one of those guys and has done something about it by creating a pretty neat solution he calls the PiMagic. It’s a Pi Plate that has an on board ATMEGA328 running an Arduino bootloader. The RaspPi and the Arduino communicate via UART as [Steve] felt it was a bit simpler than going the SPI or I2C route.

The RaspPi GPIO’s run on 3.3v and the ATMEGA328’s like 5v. To solve this, the PiMagic has a Level Shifter that keeps the I/O of the two boards happy. Older Pi’s had a problem burning out PCB traces when supplying too much current on the 5v supply line. [Steve] threw in a fuse that will burn out before the Pi does to ensure that no Pi’s were harmed in the making of this project.

Now that a bunch of I/O are available, how do you physically access them? Well, the PiMagic has female headers in the typical Arduino layout. This way any Arduino Shield will plug right in. [Steve] made all his source files available for those who want to make one themselves. Find an assembly video after the break.

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THP Semifinalist: Secure Your Internets with Web Security Everywhere


[Arcadia Labs] has created a great little device in Web Security Everywhere, a semifinalist in The Hackaday Prize. At the center of it all is UnJailPi, a Raspberry Pi device which can act as a secure router between a protected network and the unprotected internet. UnJailPi can create OpenVPN and Tor connections on the fly from its touch screen interface. The full details are right up on [Arcadia's] Hackaday.io project page.

One of the most amazing things about the project is its creator, [Arcadia Labs]. [Arcadia] started from square one learning python just 1 year ago. Since then he’s become a proficient python coder, and created UnJailPi’s  entire user interface with pygame.

[Arcadia] is also working with simple hand tools. He has no access to the CNC routers, 3D printers, or milling machines used in many of the projects we see here on Hackaday. All the work on UnJailPi’s acrylic case was done with a handsaw, a file, and a heck of a lot of patience.

Currently [Arcadia's] biggest hurdle is finding a good power supply for his project. UnJailPi is designed to work both on AC or an internal battery. His current power circuit throws off enough heat that the Raspberry Pi resets while the battery is charging.

We’re sure [Arcadia] will figure out his power issues, but if you have any suggestions, leave a comment here, or head over to the project page and let him know!

SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.

Unlock on LAN Apartment Security

Unlock on LAN

Here’s a cool little variation of that handy little function called Wake on LAN — [Jonathan] found himself locked out of his apartment one too many times, so he decided to add his own fail safe backup in order to get inside without a key — using a Raspberry Pi of course.

His apartment is one of those older style ones where the door is always locked and you use a buzzer to let someone in (or a key to get in yourself). This made it super easy to add some internet connectivity to the system. [Jonathan] tapped into the buzzer with a relay since the system uses medium voltage AC to operate. A Raspberry Pi triggers a transistor using its GPIO to click the relay on and off, effectively controlling the lock.

Using a WiFi dongle he’s connected the Pi to his home network and written a simple perl script to trigger the relay — all he has to do is visit a URL on his phone or computer and the door will unlock instantly!

Once the system worked [Jonathan] soldered all the components onto a breadboard and hooked it up. He still needs an enclosure for it, but it’s been working well since he installed it.

Another option would be to use an RFID tag system through the door, which could be pretty cool as well.


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