Hack a Day

[Osgeld] is showing off what he calls a sanity check. It’s the first non-breadboard version of his Pocket Serial Host. He’s been working on the project as a way to simplify getting programs onto the Apple II he has on his “retro bench”. When plugged in, the computer sees it as a disk drive.

The storage is provided by an SD card which is hidden on the underside of that protoboard. This makes it dead simple to hack away at your programs using a modern computer, then transfer them over to the retro hardware. The components used (starting at the far side of the board) are a DB9 serial connector next to a level converter to make it talk to the ATmega328 chip being pointed at with a tool. The chip below that is a level converter to get the microcontroller talking to the RTC chip seen to the right. The battery keeps that clock running when there’s no power from the 5V and 3.3V regulators mounted in the upper right.

The video after the break shows off this prototype, the breadboard circuit, and a demonstration with the Apple II.

[Thanks Brendan]

[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.

You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino. You can see the schematic as well as a demo clip after the break.

This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi's] setup provides a digital signal that at most only needs to be debounced.

This wall hanging would look great even if it did no more than light up. But thanks to a unique controller it’s meant to work as an interactive display for your living area.

The rectangles and votive candle cups are a set of three store-bought hangings. But lighting the candles and remembering to blow them out was a pain, so [Adiel Fernandez] decided to add the LEDs to make the job easier. But why stop at that, in addition to an RGB light for each cup he made them fully addressable. It’s all the better for a light show, but this also opens up the arena for all manner of different uses.

Accompanying the wall installation is a palm-sized cube meant to sit on the coffee table. Whichever side of the cube us up sets the function for the display, with a rotation tweaking the function, and a fast spin used as a select. If the power icon is on the side facing up, a fast spin will turn the display on or off. There are also functions for weather, temperature, transportation (we were thinking something like a bus schedule notifier but it’s actually a bit different) and animation patterns. After the break you can watch a demo of the cube functionality.

[Thanks Elias]

If you’re going to use your bicycle as transportation at night you really must have a head and tail light in hopes that the crazy drivers don’t hit you. For good reason, these lights don’t turn themselves off. But [Miceuz] kept forgetting to shut it down upon arrival and always ended up with dead batteries. His quest for an auto-off feature that actually worked ended in a brilliant and simple add-on circuit.

He first thought about using an accelerometer, but couldn’t find one that fit the bill without also adding a microcontroller. He came up with an even simpler circuit, which can be seen at the base of the black plastic housing. It’s a bit of copper clad board with a small spring attached. The spring completes an RC timer circuit which drives a MOSFET. When that circuit is charged, the MOSFET connects power to the bike light. When the cap runs out the MOSFET threshold cuts power and everything turns off. Since the spring jiggles while he rides it provides the momentary connection necessary to charge the capacitor. Stay stationary for about 30 seconds and the auto-off kicks in.

Karaoke just isn’t fair. Not only do you have people who can’t sing choosing to belt out extremely difficult to sing songs, but the variety of songs generally isn’t that great. In an effort to make the karaoke situation at the pubs he frequents better – or worse, depending on how you look at it – [cosmic blooper] is now bringing a vocal effects processor to karaoke. Yes, now he’s got pitch shifting that takes him into [Bieber] territory, and auto tune to emulate the [T-Pain] and the Black Eyed Peas.

To bring the world of synths and effects to a karaoke party, [cosmic blooper] took a battery-powered Kaoss Pad and attached it to his belt with the help of some sheet metal. An RCA to XLR adapter connects the Kaoss Pad to the karaoke microphone, while a mic of questionable quality takes [blooper]‘s voice to be transmuted into a horrifying display of effects and pitch shifters.

There’s no video of [cosmic blooper]‘s karaoke machine in action, but he tells us he’ll be getting one up soon.

Your Raspberry Pi has on-board connectors for cameras and displays, but until now no hardware demigod has taken up the challenge of connecting an image sensor or LCD to one of these ports. It seems everyone is waiting for official Raspi hardware designed for these ports. That wait is just about over as the Raspberry Pi foundations is hoping to release a camera board in the coming weeks.

The camera module is based on a 5 megapixel sensor, allowing it to capture 2560×1920 images as well as full 1080 video with the help of some drivers being whipped up at the Raspberry Pi foundation.

Considering the Raspi USB webcam projects we’ve seen aren’t really all that capable – OpenCV runs at about 4 fps without any image processing and about 1 fps with edge detection – the Raspberry Pi camera board should be less taxing for the Pi, enabling some really cool computer vision projects.

The camera board should be available in a little more than a month, so for those of us waiting to get our hands on this thing now, we’ll have to settle for the demo video of the Pi streaming 1080p video to a network at 30fps after the break.

[Elvis Impersonator] spent three full days but in that time he managed to hand control of everything in his house over to Siri. The technique used is a familiar one. A Raspberry Pi running SiriProxy listens for commands from the iPhone and acts on them based on [Elvis'] predefined configuration. The difference here is that it’s not just a single device (read: lamp) that is being controlled to prove the concept. His video (embedded after the break) shows him operating an entire range of devices in his home.

The demonstration starts off with his garage door being opened and closed. From the YouTube video description we know that he’s using Trendnet IP cameras and it looks like one of them lets him see if he remembered to close the garage.  Next he disarms his home security system as shown in the image above. From there he adjusts the Nest thermostat, switches off the living room lights, and changes the TV channels.

We think the need to give voice commands would get old pretty quickly. But that aside we applaud his work to pull everything together into one single interface.

[Patrick] wanted to have centralized sensing and control over various parts of his house. His Raspberry Pi Home Automation System integrates a bunch of functionality in one rack mount package, salvaged from an old network switch.

The automation system is based on a Raspberry Pi running Arch Linux, which talks to an ATmega over SPI. We’ve seen this setup used many times before to add additional ports to the Raspberry Pi, but what makes [Patrick]‘s build unique is the amount of control he’s built into the system.

The box controls outdoor lighting at sunset and sunrise, generates wakeup calls, controls IR cameras, and plays sounds based on events. It’s capable of monitoring sump pump water level, the state of a house alarm, and more. A custom REST API is used to interact with the device. This allows for programs on any platform to interface with his home, and acts as an API for his house.

[Patrick] provides a lot of details in his build log, which should be helpful to anyone looking to roll their own home automation system. The source is also provided.

When testing power supplies or LEDs, a constant current dummy load is needed. These devices will draw a constant amount of current, regardless of the voltage at the input terminals.

[Nick] was looking for a load to test out a power supply, and found commercial offerings to be too large, too powerful, and most importantly, too expensive. This lead to the design of the Re:load, his open source alternative.

Like other constant current sources, the Re:load uses an opamp to control a pass element. While most constant current loads will just use a transistor, [Nick] opted for a BTS117 smart low side switch IC. This device has a built in current limiter, over-voltage protection, over-temperature protection, and short circuit protection, which makes it much safer. The project write up goes into detail on how the device works.

If you need a constant current load, [Nick] is selling kits on Tindie. All the design files are available on Github so that you can build your own.

Here’s a collection of tricks to get over some surface mount prototyping issues the next time you find yourself in a bind. But first we have to address the soldering atrocity seen on most of the components above. [Rxdtxd] admits he’s using a firestick for soldering his SMD parts. The non-brand 40W iron is just about the worst thing he could be using (well, we guess a candle would be worse). Try to overlook those joints and enjoy his solutions to a couple of other problems.

First up is what to do when you lift a fine-pitch trace like would be found on a TQFP footprint. The fix for this is to grab a junked transformer and use a bit of the enameled wire from the wrappings as a jumper. The wire is quite fine, and the insulation will burn off when soldered which means you don’t need to strip it first.

The second and third tricks both deal with resistors. As you can see above he placed two 1K resistors on a single resistor footprint to make his 2k resistor. The 0603 packages were both soldered standing on end, then connected with a lead from a through-hole component. The other resistor hack piles five components on top of each other to build resistance in parallel. This is not a great idea as it will fail over the long-term, but it will get you though the prototyping stage as long it doesn’t require precise tolerance.

Ask around and chances are you can find a friend or family member that still has their early generation Kindle but doesn’t use it anymore. There are quite a number of different things you can do with them, and now there’s a single Launcher that works for all models of hacked Kindles. KUAL is the Kindle Unified Application Launcher.

Loading the launcher on your device does require that it be Jailbroken/Rooted, but that’s really the entire point, right? Once on your device the system is easy to configure. Menus themselves can be customized by editing the XML and JSON pair for each list. The screenshot on the left illustrates some of the applications you might want to run. We could see a VNC viewer being useful, and everyone likes to have games – like Doom II or the entire Z-machine library – on hand when they unexpectedly get stuck somewhere. But MPlayer? Does anyone actually use their ePaper device to watch videos?

Get serious about your shell scripting skills and maybe you can pull this one off. It’s a game of snake played in a BASH shell. It seems like a coding nightmare, but the final product turns out to be organized well enough for us to understand and took less than 250 lines of code.

[Martin Bruchanov] started on the project after pining for an old DOS game called Housenka. It’s another version of the classic Snake game which we’ve coded ourselves and seen in several projects including this head-to-head version using musical recorders as controllers. When using a terminal emulator capable of ANSI sequences the game is displayed in color using extended characters.

We give [Martin] bonus points for the way he wrote about his project. It describes the mechanics most would be interested in, like how the user input is captured and what drives the update function and food generation. The rest of the details can be gleaned by reading through the code itself.

The goal of The Deconstruction is to bring people together (physically and digitally) to share ideas, collaborate, create, problem solve, and have a good time.   The event is open to anyone, anywhere, of any age and skill level.

If you enjoy a bit of good competition and feel like taking on a little bit of a challenge, you should definitely check out The Deconstruction. This event pits a bunch of teams from all over the place against each other in a timed hack-a-thon.  The whole time they are building their project, they’re broadcasting live using their webcams too.

If this brings to mind the Red Bull Creation contest, it is because the root idea is from the same guy [Jason Naumoff]. When I met with him last year in New York, he clued me in that he was working on something much more open ended and inclusive.  The Deconstruction is that thing. He explained that they’re really hoping to reach out to families, clubs, and high school groups as well as the usual hackerspaces.

Join up, make something cool, have fun.

Check out the toy this solder is using. It’s a tiny remote-controlled helicopter. The thing comes in a kit that includes a small tablet through which the nose-mounted camera image can be viewed. These are in use in Afghanistan by the UK Military. The purpose is to help protect foot soldiers by allowing them to perform discrete reconnaissance. What would you pay for this type of life saving technology? How does $31 million for 160 units sound? For that price we expect eight propellers and a cinema quality camera.

The drone is manufactured by Prox Dynamics. They’ve been in development since 2008 and you can bet that a lot of that time went into making it “inaudible” which is the main difference we see between this and hobby-built versions. For now you’ll have to deal with trying to make your own since they will only sell to the government.

The best we can do for you when it comes to video of the thing is prototyping footage from 2009 (after the break). If you have a link to a newer clip we’d love to see it in the comments.

[via Reddit]

[John] was looking for a project for his newly acquired Raspberry Pi and decided to include his dog in the fun. although his finished project looks a lot like an old time camera, it’s actually a web-connected treat dispenser that uses his dog’s email address for dispensation.

Let’s take a look at the hardware from top to bottom. There’s a camera with a eagle’s eye shot of his furry friend waiting for treats. The cylinder below that is the motor which drives the treat dispenser. You can see the chain tensioner on the back which connects the motor to the tube dispenser in the center of the box. Just above that outlet is the character display which gives feedback to anyone watching the dispenser. Nearing the bottom is a hopper that catches the treats, then flips over to dump them onto the floor. And finally at the bottom is a slot for the Raspberry Pi which drives everything.

Most of [John's] projects revolve around CNC work. In addition to the demo video found after the break there’s a second that focuses on CAD design. About half way through that clip he gives us a close-up tour of all the hardware.

[Thanks Joseph]

Evern wanted to write your own Atari 2600 games? This won’t get you quite that far, but it will teach you the very basics. It’s an assembly tutorial for the 6502 processor. The nice thing is that you need nothing more than your browser to participate thanks to the embedded JavaScript emulator which acts as assembler, machine, and debugger in one.

The 6502 was in a lot of early equipment. In addition to the previously mentioned Atari they can be found in the Commodore 64, Apple II, and the original NES. You can even find folks building their own computers around the chip these days (most notable to us is the Veronica project). The guide starts off slowly, providing a working program and challenging the reader to play with to code in order to alter the outcomes. It moves on to an overview of registers and instructions, operators and branching, and culminates in the creation of a simple game.

[Thanks Mathilda]

It’s a real bummer when injection molded plastic parts break. We’ve never found a gluing technique that works for a part which is exposed to force like the clamp on this camera tripod. But [Matthias Wandel] may be on to something. Here he’s using nichrome wire to reinforce the broken plastic part.

The repair process is demonstrated in full in the video after the break. He scavenged the wire from the heating element of broken hair driers. the idea is to wrap the wire across the broken piece, then apply power from a bench supply. This heats the wire, which can then be pulled beneath the surface of the plastic. [Matthias] likens it to using rebar in concrete.

His implementation could be improved just a bit. Getting the wire to embed evenly is a problem, but using a pair of pliers instead of just alligator clips may yield better results.

[via Reddit]

This Space Invaders game does more with less. [Rjk79] managed to make a video game using a two-line character display. The game consists of a wave of invaders on the top line, with the defender cannon on the bottom. The invader isn’t just stationary, but randomly moves to the left and the right. The image above captured a little bit of motion blur from the defender moving into position before firing on the enemy.

An Arduino board controls the 16×2 HD44780 character display. The game also includes sounds generated by the piezo buzzer seen on the breadboard. All the way to the right you can see the Wii Nunchuk breakout board which provides directional control and the firing trigger. If you want to recreate this one for yourself [Rjk79] is sharing the source code on Pastebin. There’s also a demo video found after the jump.

If you don’t have a character LCD on hand you might try this other Space Invaders clone that uses an 8×8 led matrix.

We admit that this project doesn’t have very many details available, but it was just too neat for us to pass up. It’s a small linear motor which [ligonapProduktion] built after seeing a very brief description of a commercially available version.

The video after the break shows him testing the motor. In this screenshot he’s holding the center shaft while the coil assembly moves back and forth. But it works with a stationary coil moving the rod as well. The motor is basically a modified solenoid. There are sixteen neodymium magnets inside the shaft. The set of four coils is driven by an ATtiny44. Just like a stepper motor, energizing the coils in the correct order pushes against the rare earth magnets creating motion.

We’re not sure if he has any use in mind for this build. For us we just like to see the concept in practice (we feel the same way about a homopolar motor build).

[via Reddit]

Here’s an LED and Button shield for the Stellaris Launchpad (translated) which you can fabricate at home. It gives you access to a 5×5 matrix of LEDs, and adds four more buttons. In order to cut down on the number of I/O pins required to operate the lights [Cosimo] is using the concept of Charlieplexing. This lets him get away with just six driver pins and four button pins.

It’s not just the finished product that interests us here. The fabrication itself is worth clicking through to his project post. What initially caught our eye is the use of Kapton tape as an insulator so that clipped off LEDs could be used as jumpers flat against the top side of the board before populating the LEDs themselves. After those are soldered in place he masks them off, as well as the button footprints, and uses spray paint to protect the top side of the board. The final look is more polished than most at-home project boards.