classic hacks

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[Ben Krasnow] Shows Us How A Crookes Radiometer Works

November 15, 2014 by 21 Comments

[Ben Krasnow] is tackling the curious Crookes Radiometer on his Applied Science YouTube channel. The Crookes Radiometer, a staple of museum gift shops everywhere, is a rather simple device. A rotor with black and white vanes rotates on the head of a needle. The entire assembly is inside a glass envelope. The area inside the glass is not at a hard vacuum, nor is it filled with some strange gas. The radiometer only works when there is a partial vacuum inside.

The radiometer’s method of operation was long misunderstood. Sir William Crookes and James Clerk Maxwell both believed that the vanes moved due to the pressure of the photons hitting the vanes. If that were true though, the radiometer would spin in the opposite direction it normally does when held near a light source.  It was eventually discovered that the system is a thermodynamic one. [Ben] proves this by cooling down the radiometer’s glass with a can of freeze spray.  The radiometer immediately begins spinning backwards, with no light source present.

From there [Ben] mounts the rotor of a radiometer inside his vacuum chamber, which many will recognize as the chamber from his DIY electron microscope. As expected, the vanes don’t spin at a hard vacuum. In fact, [Ben] find the vanes spin fastest when the pressure is about 7 mTorr.

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Multi-target IDE For 8-Bit CPUs

November 15, 2014 by 19 Comments

A long time ago, [Martin] played with old 8-bit computers. Recently, he’s been honing his assembly skills again, and the idea of an IDE for a boatload of old systems came to him. After a year of work, he announced a multitarget IDE for 8-bit computers that works in your browser.

The project is called ASM80, and includes a code editor, a workspace to put all your code, compilers for the 8080/8085, Z80, 6502, 6800 and 6809 CPUs, emulators for all these CPUs, and emulators for a few Czech computers, the ZX Spectrum, and a few of [Grant Searle]’s single board computers.

What makes this project interesting is the syntax for all the different CPUs is pretty much the same. It’s a real, modular code editor that supports macros and everything you would expect for a code editor for ancient computers.

You can check out an assembler description here. [Martin] also has an offline, desktop-based version of ASM80 called IDE80, with a video demo of that below.

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Hand-Machined Companion Cube Can Be Destroyed And Rebuilt

November 15, 2014 by 7 Comments

[Michael Gainer] is a big fan of Portal, and it shows in the Weighted Companion Cube he made. [Michael] hand-machined the many pieces that comprise the Cube’s body and medallions out of 6061 aluminum. Dykem was used to transfer the marks for accurate machining, and the color is powder-coated to a heat tolerance of 400F. A CNC was used to make the distinctive hearts. [Michael] notes the irony was “very Portal” in having them cut by a heartless machine when everything else was done manually. The attention to detail is striking, the level of design more so when [Michael] proceeds to incinerate the poor Companion Cube with a brush burner. In the video shown at the link above, the Cube falls apart as the glue holding it together melts. When all is said and done, just grab more glue to bring that Cube back to its six-sided glory. Repeat to your heart’s content. Huge success! We have to be honest, after seeing all those pieces, we aren’t sure we’d want to do this very often. Companion Cubes have been featured in various iterations on Hackaday before, but they were never built with the idea of repeatedly destroying and rebuilding them. This novel take would make GlaDOS proud.

[Michael] has plans to put an Android device inside it with some light and temperature sensors. He wants to give it a voice resembling Portal’s turrets so it can whine when it needs to be charged or scream when it’s too hot or cold. He dubs this next project the “Overly Attached Weighted Companion Cube.” It wouldn’t be a good idea to incinerate this upcoming version, though we’d probably be inclined to if it demanded so much of our attention!

 

Teensys And Old Synth Chips, Together At Last

November 10, 2014 by 25 Comments

The ancient computers of yesteryear had hardware that’s hard to conceive of today; who would want a synthesizer on a chip when every computer made in the last 15 years has enough horsepower to synthesize sounds in software and output everything with CD quality audio? [Brian Peters] loves these old synth chips and decided to make them all work with a modern microcontroller.

Every major sound chip from the 80s is included in this roundup. The Commodore SID is there with a chip that includes working filters. The SN76489, the sound chip from the TI99 and BBC Micro are there, as is the TIA from the Atari consoles. Also featured is the Atari POKEY, found in the 8-bit Atari computers. The POKEY isn’t as popular as the SID, but it should be.

[Brian] connected all these chips up with Teensy 2.0 microcontrollers, and with the right software, was able to control these via MIDI. It’s a great way to listen to chiptunes the way they’re meant to be heard. You can check out some sound samples in the videos below.

Thanks [Wybren] for the tip.

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Wax Motors Add Motion To Your Projects

November 10, 2014 by 19 Comments

[electronicsNmore] has uploaded a great teardown and tutorial video (YouTube link) about wax motors. Electric wax motors aren’t common in hobby electronics, but they are common in the appliance industry, which means the motors can be often be obtained cheaply or for free from discarded appliances. Non-electric wax motors have been used as automotive coolant thermostats for years.  Who knows, this may be just what the doctor ordered for your next project.

As [electronicsNmore] explains, wax motors are rather simple devices. A small block of wax is sealed in a metal container with a movable piston. When heated, the wax expands and pushes the piston out. Once the wax cools, a spring helps to pull the piston back in.

The real trick is creating a motor which will heat up without cooking itself. This is done with a Positive Temperature Coefficient (PTC) thermistor. As the name implies, a PTC thermistor’s resistance increases as it heats up. This is the exact opposite of the Negative Temperature Coefficient (NTC) thermistors we often use as temperature sensors. PTC’s are often found in places like power supplies to limit in rush current, or small heating systems, as we have in our wax motor.

As the PTC heats up, its resistance increases until it stops heating. At the same time, the wax is being warmed, which drives out the piston. As you might expect, wax motors aren’t exactly efficient devices. The motor in  [electronicsNmore’s] video runs on 120 volts AC. They do have some advantages over solenoid, though. Wax motors provide smooth, slow operation. Since they are resistive devices, they also don’t require flyback diodes, or create the RF noise that a solenoid would.

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Interactive Sound With Glove And Tape

November 9, 2014 by 14 Comments

Here’s a way to explore new spaces in untraditional manners: a sonophore, or a glove equipped with a tape heads meant to explore spaces with magnetic tape tracing the walls.

This project is a followup to the analogue tape glove from a few years ago. In that project, aligned strips of magnetic tape cover a canvas, leaving anyone wearing the glove to track their hand horizontally swiping across different tracts, or vertically listening to each track.

This project takes a glove similar to the analogue tape glove, but the tape is spread out along the walls of the installation. There’s no way of knowing what strange voices are contained on the tapes; the only way to know is to explore the space.

Video of the project below. It’s a Vimeo, so you know it’s artistic.

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Breadboarding A 68000 Computer In Under A Week

November 8, 2014 by 16 Comments

We’ve been lurking over at Big Mess ‘o Wires as [Steve] geared up for his 68000 computer build. One of his previous posts mentioned a working breadboard version but we figured it would be a ways off. Surprise, he’s got it working and what you see above took just 6 days of “occasional work” to get running.

The chip in use is actually a 68008 but we remember reading that he does plan to migrate to a 68000 because this one lacks the memory pins to address more than 1 MB of RAM. The trick here was just to get the thing running and he made some common choices to get there. For instance, he grounded the /DTACK in much the same way [Brian Benchoff] explained in his own 68k build.

We’re not sure if his address decoding was a time saver or not. If you study [Steve’s] original planning post you’ll learn that he’s going to use programmable logic to handle the address decoding. But above he wired up 74-series logic chips to perform these functions. On the one hand you know your Hardware Description Language isn’t the problem, but did you terminate one of those wires where you ought not?

Additional tripping points include a bouncing reset pin. Looking at that we’d tell [Steve] there’s a problem with his chip, except that this was his first thought as well. He went the extra mile by building and testing a replica of the reset system. This makes our brain spin… shouldn’t the reset be among the most reliable parts of a processor?

At any rate, great work so far. We can’t wait to see where this goes and we hope that it unfolds in a way that is as exciting as watching [Quinn Dunki’s] Veronica project take shape.