Minicomputers On Microcontrollers

January 24, 2014 by 28 Comments

Developed in the very late 60s and through the 70s, the PDP-11 series of minicomputers was quite possibly the single most important computer ever created. The first widely distributed versions of Unix and C were developed on the PDP-11, and it’s hardware influence can be found in everything from the Motorola 68000 to the MSP430.

When [Dave Cheney] saw the recent 8086 simulator written in 4kB of C code, he realized simulating entire computer systems doesn’t actually require a whole lot of resources outside a big chunk of memory. Armed with an Arduino Mega clone, he set out on one of the coolest projects we’ve seen in a while: simulating a PDP-11 on an AVR.

[Dave] used an ATMega2560-powered Arduino Mega clone with an Ethernet module for the hardware of this build. Attached to it is a shield filled up with a pair of RAM chips that expand relatively limited amount of RAM on the ‘Mega.

So far, [Dave] has his simulated system booting Unix V6 off an SD card. For PDP-11 storage, he’s also simulating an RK05 disk drive, a massive 14 inch platter containing 2.5 Megabytes of data. Compared to the original PDP-11/40, [Dave] estimates his machine is about 10 times slower. Still, an original 11/40 system fills multiple server racks, and the most common installations consume several kilowatts of power. The Arduino Mega can fit in a pocket and can be powered over USB.

Future developments for this system include improving the accuracy of the simulator, running more advanced operating systems and the DEC diagnostic programs, and possibly speeding up the simulation. We’d suggest adding some switches and blinkenlights on an additional shield, but that’s just us.

All the code can be found on [Dave]’s git, with a description of his SPI RAM shield coming shortly.

Adventures In Hackerspacing: An Interview With Chris Boden Of The Geek Group

January 24, 2014 by 65 Comments

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There are some big hackerspaces out there.
And then there’s The Geek Group.
It takes a certain chutzpah to convert a 43,000 foot former YMCA into a hackerspace. And an epic hackerspace it is, complete with 5 axis CNC machines, 3d printers, and of course, giant robots romping through a forest of Tesla coils.  The Geek Group has performed live demos in front of thousands of people over the years, and inspired tens of thousands more via the internet. You don’t work this big without having some big adventures, and The Geek Group is no exception. They’ve been through roof leaks, gas pipe breaks, surprise tax bills and angry neighbors. They’ve also been dealing with their current adventure, fire.

Unless you’ve been under a rock the last few weeks, you’ve probably read about the recent fire, and ensuing cleanup at The Geek Group labs. We’ve covered the fire and its cause here on Hackaday, with no small amount of drama in our comments section. There is a small but vocal minority who don’t have many good things to say. Accusations of cults, safety violations, and tax evasion often fly. While some groups would take this lying down, the geek group put on their flame proof suits and wade through the comments. None more vocally than [Chris Boden], the president, CEO and founder.

DISCLAIMER: The interview contains questionable content and some profanity (which we’ve altered as grawlix). We have posted the transcript as it was captured, which includes some spelling and grammar issues. Please consider these things before clicking through to the interview itself.

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Solar Hot Dog Cooker Does It With Parabolic Mirrors

January 24, 2014 by 26 Comments

For a university project [Adam Libert] decided to make his very own parabolic hot dog cooker. Now, we must say, this is a project that could probably be cobbled together in a weekend from scraps, but since it was for a lab, [Adam] decided to go all out — complete with a perfect laser cut frame.

The objective of the lab was to design a project that can use solar radiation to accomplish a task, and being partial to hot dogs, the hot dog cooker was a natural choice. He designed the parabolic mirror to focus 1/5th of a square meter of sunlight directly at a hot dog. To do this, he laser cut the frame out of MDF, and using tinfoil, toothpicks, and poster paper, assembled the mirror. The whole thing cost less than $5 (ignoring laser time) and can be setup in a matter of minutes.

He determined the heat output of the cooker to be around 10W at the hot dog, which means he was able to bring the hot dog to 150°F in about 10 minutes — which was surprisingly close to his original calculations, because let’s face it, tin foil is hardly an ideal mirror.

Interested in other solar cookers? Why not cover a satellite dish in foil tape? Or if you want a quicker-cooked-hot-dog, why not plug it directly into the wall?

SLDongle: The Microcontroller Gift That Keeps On Giving

January 24, 2014 by 14 Comments

It must be nice to be one of [kiu]’s colleagues. Some people pass out chocolates or stress balls at work as Christmas gifts, but [kiu] made a bunch of SL dongles to introduce his colleagues to the world of microcontrollers.

The dongles are based on the ATMega88PA and work on three levels to provide something for everyone. The no-experience-necessary option is to plug it in to a USB port and admire the light show sequences. If you know enough to be dangerous, you can remotely control the LEDs from a USB host using [kiu]’s sldtool for Linux or Mac. He originally included examples that visualize CPU utilization and ultimately added a Ruby-based departure countdown for the next outbound train at the nearby station.

If you’re 1337 enough you can flash your own C or assembly code via USB. Holding down the button during power-up lets you use the dongle as a USBasp so it can be flashed with avrdude. [kiu] says the bootloader can’t be unlocked through software and is theoretically unbrickable. Stick around after the break to see the full demo.

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Fun With Wooden Balls

January 24, 2014 by 35 Comments

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Have you ever found the need to make your own wooden balls for a project? To be frank, we haven’t either! But seriously — how would you do it? Well, lucky for us, Hackaday Alum [Jeremy Cook] has experimented with a few different methods.

He was originally inspired by this video from [Philip Stephens] who makes them completely by hand using a hand-made hole saw. Not wanting to spend hours making a ball, he thought about ways to automate it — well, kind of.

His first attempt was to use a mill and a rudimentary rotary index table consisting of a wood clamp — Hold a wooden dowel in place, hole saw halfway through, rotate in the clamp, repeat times infinity. Eventually you’ll be left with a wooden ball whose sharp edges you can just break off. Not very satisfied with this method, he discovered a Reddit thread on making wooden balls with a rather ingenious method… Stick around after the break to see how.

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ARM Debugger For Nearly One Dollar

January 23, 2014 by 58 Comments

Oh that title is so misleading. But if you squint your eyes and scratch your noggin it’s almost true. Thanks to the hard work of [Peter Lawrence] it is now possible to hack together an extremely inexpensive CMSIS-DAP ARM debugger.

Let’s talk about function and we’ll get back to cost later. CMSIS-DAP is a standard that gives you the kind of breakpoint control you expect from a proper debugger. In this case [Peter] implemented the standard using 4k words of space on a PIC 16F1454. This lets it talk to the debug port on ARM chips, and the bootloader (also written by him) doubles as a USB-to-UART bridge. Boom, done. OpenOCD (and a couple of other software packages) talks to the PIC and it talks to the ARM. Nice.

Back to the cost question. You can get a 16F1454 for nearly a dollar when you order in quantity. If you cut up an old USB cable, recycle some jumper wire, and already have power and decoupling on hand, you’re in business for nearly one dollar.

All-Terrain RC Car Has More Torque Than Your Grandpa’s Wheelchair

January 23, 2014 by 31 Comments

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[Charles] and his brother have been members of their school’s FIRST robotics team for many years, and using some of the knowledge they acquired during it, they have put together this awesome all-terrain, super over-powered, RC car — and soon to be robot.

It’s built like a tank using 1″ square steel tubing and custom corner brackets made of 1/8″ thick steel. Heavy duty U-bolts hold the over-sized 5/8″ axles, and everything is driven using #35 roller chain. A large 12V sealed lead acid battery powers two CIMs (FIRST Robotics motor) with the AndyMark CIMple gearbox — these give the car tons of torque, and it can even do wheelies!

The really cool part of this project is the method of remote control. He’s using a regular old Xbox controller that an Arduino Uno listens to through a USB host shield and the original Xbox USB receiver. Simple, but totally effective.

The project is not yet complete, and he’s planning on fully equipping it with lights, a larger battery, a roll-cage, a camera system, and some kind of manipulator tool. Check out the test drive video after the break!

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