The Tiny, Awesome Class D Amp

April 3, 2014 by 21 Comments

ClassD

In one of [Hans Peter]’s many idle browsing sessions at a manufacturer’s website, he came across a very cool chip – a 10 Watt class D amplifier chip. After the sample order arrived, he quickly put this chip in a box and forgot about it. A year or so later, he was asked to construct a portable boom box kit for a festival. Time to break out that chip and make a small amplifier, it seems.

The chip in question – a Maxim MAX9768 – is a tiny chip, a 24-pin TQFP with 1mm pitch. Hard to solder freehand, but this chip does have a few cool features. It’s a filterless design, very easy to implement, and perfect for the mono boombox project he was working on. A simple, seven component circuit was laid out on a breadboard and [Hans] got this chip up and running.

For the festival, a breadboarded circuit wouldn’t do. He needed a better solution, something built on a PCB that would work well as a kit. The requirements included the MAX9768 chip, a guitar preamp, stereo to mono summing, and through-hole parts for easy soldering. The completed board ended up being extremely small – 33.6mm by 22.5mm – and works really great.

After the festival, [Hans] found a 20 Watt chip and designed an all-SMD version of the board. Just the thing if you ever want to stuff a tiny amplifier into a crevice of a project.

Arduino Controlled Dahlander Motor Switch

April 2, 2014 by 15 Comments

 

Dahlander Switch

[Jean-Noel] is fixing a broken Lurem woodworking machine. This machine uses a three-phase Dahlander motor, which has three operation modes: stop, half speed, and full speed. The motor uses a special mechanical switch to select the operating mode. Unfortunately, the mechanical bits inside the switch were broken, and the motor couldn’t be turned on.

To solve the problem without sourcing a new switch, [Jean-Noel] built his own Arduino based Dahlander switch. This consists of three relays that select the wiring configuration for each speed mode. There’s also a button to toggle settings, and two lamps to show what mode the motor is currently in.

The Arduino runs a finite-state machine (FSM), ensuring that the device transitions through the modes in the correct order. This is quite important, since the motor could be damaged if certain restrictions aren’t followed. The state machine graph was generated using Fizzim, a free tool that generates not only FSM graphs, but also Verilog and VHDL code for the machines.

The final product is housed in a DIN rail case, which allows it to be securely mounted along with the rest of the wiring. The detailed write-up on this project explains all the details of the motor, and the challenges of building this replacement switch.

Happiness Is Just A Flaming Oxy-Fuel Torch Away

April 2, 2014 by 13 Comments

The Egg-Bot is pretty awesome, we must say. But if you have one, you end up with lot of delicate, round things rolling around your abode and getting underfoot. Warmer weather is just around the corner, so segue from spring gaiety to hot fun in the summertime with the MarshMallowMatic kit from [Evil Mad Scientist].

The MarshMallowMatic is a CNC oxy-fuel precision marshmallow toaster based on the Ostrich Egg-Bot design. Constructed from flame-retardant plywood, it is sure to add an element of delicious danger to children’s birthday parties and weekend wingdings alike. You don’t have to get too specific with those BYOM invitations because this bad boy will torch standard and jumbo marshmallows like a boss.

The kit includes a 5000°F oxy-fuel torch and a 20 ft³ oxygen tank, but the tank comes empty and you’ll have to supply your own propane, acetylene,  or hydrogen. It comes with adapters to fit disposable propane and MAPP cylinders, which are also not included. However, you will receive a fine selection of sample marshmallows to get you started. Watch the MarshMallowMatic fire up some happiness after the break. You could toast a special message and load it into this face-tracking confectionery cannon to show how much you care.

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3D Printed Splint Saves Baby’s Life

April 2, 2014 by 31 Comments

3D-printed-breathing-device-2a

Here’s another heartwarming story about how 3D printers are continuing to make a real difference in the medical world. [Garrett] is just a baby whose bronchi collapse when breathing — he’s been on a ventilator for most of his life — Until now.

[Scott Hollister] is a professor of Biomedical Engineering and Mechanical Engineering, as well as being an associate professor of surgery at the University of Michigan. Between him and [Doctor Glen Green], an associate professor of Pediatric Otolaryngology, they have created a bioresorbable device that could save little [Garrett’s] life.

By taking CT scans of [Garrett’s] bronchi and trachea, they were able to create a 3D model and design a “splint” to help support the bronchi from collapsing during normal breathing. If all goes well, within 3 years, the splint will dissolve in his body and he will be able to breath normally for good. The material in question is a biopolymer called polycaprolactone, which they were actually granted emergency clearance from the FDA to use for [Garrett]. They used an EOS SLS based 3D printer.

The surgery was successful, and [Garrett] is now on the road to recovery. Stick around for a few videos showing of the printing process and surgery.

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[Bunnie] Launches The Novena Open Laptop

April 2, 2014 by 60 Comments

Today [Bunnie] is announcing the launch of the Novena Open Laptop. When we first heard he was developing an open source laptop as a hobby project, we hoped we’d see the day where we could have our own. Starting today, you can help crowdfund the project by pre-ordering a Novena.

The Novena is based on the i.MX6Q ARM processor from Freescale, coupled to a Xilinx Spartan 6 FPGA. Combined with the open nature of the project, this creates a lot of possibilities for using the laptop as a hacking tool. It has dual ethernet, for routing or sniffing purposes. USB OTG support lets the laptop act as a USB device, for USB fuzzing and spoofing. There’s even a high speed expansion bus to interface with whatever peripheral you’d like to design.

You can pre-order the Novena in four models. The $500 “just the board” release has no case, but includes all the hardware needed to get up and running. The $1,195 “All-in-One Desktop” model adds a case and screen, and hinges open to reveal the board for easy hacking. Next up is the $1,995 “Laptop” which includes a battery control board and a battery pack. Finally, there’s the $5000 “Heirloom Laptop” featuring a wood and aluminum case and a Thinkpad keyboard.

The hardware design files are already available, so you can drool over them. It will be interesting to see what people start doing with this powerful, open computer once it ships. After the break, check out the launch video.

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Boxing + Arduino + Geometry = Awesomeness

April 2, 2014 by 3 Comments

arduino-boxing-blocker

Imagine a machine that [Anderson Silva] could throw a punch at, that would locate his fist in real time and move a punching pad to meet his moving fist. How would you do it? Kinect? Super huge sensor array? Sticking charm? What if we told you it could be done with two electret microphones, an Arduino, and a Gumstix? Yeah, that’s right. You might want to turn your phone off and sit down for this one.

[Benjamin] and his fellow students developed this brilliant proof of concept design that blocks incoming punches for their final project. We’ve seen boxing robots here before, but this one takes the cake. The details are sparse, but we’ve dug into what was made available to us and have a relatively good idea on how they pulled off this awesome piece of electrical engineering.

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MSP430-Based CTF Hardware Hacking Challenge

April 2, 2014 by 6 Comments

Hardware 'Flag'

Hacking conferences often feature a Capture the Flag, or CTF event. Typically, this is a software hacking challenge that involves breaking into targets which have been set up for the event, and capturing them. It’s good, legal, hacking fun.

However, some people are starting to build CTFs that involve hardware hacking as well. [Balda]’s most recent hardware hacking challenge was built for the Insomni’hack 2014 CTF. It uses an MSP430 as the target device, and users are allowed to enter commands to the device over UART via a Bus Pirate. Pull off the exploit, and the wheel rotates to display a flag.

For the first challenge, contestants had to decompile the firmware and find an obfuscated password. The second challenge was a bit more complicated. The password check function used memcpy, which made it vulnerable to a buffer overflow attack. By overwriting the program counter, it was possible to take over control of the program and make the flag turn.

The risk of memcpy reminds us of this set of posters. Only abstaining from memcpy can 100% protect you from overflows and memory disclosures!