Month: July 2015

Old Kindle Upcycled To Emailable Fridge Messageboard

July 29, 2015 by 15 Comments

We’ve all got a pile of old devices lying around somewhere that are waiting to be torn down for parts, or turned into something useful. [Peter Voljek] decided to do the latter with an old Kindle eBook reader, turning it into a neat message board that can be stuck onto a fridge. With the addition of some server-side Ruby code, you can send messages to this by email, and it automatically displays the last message received. Throw on some magnetic sticky tape and you have a neat fridge door noticeboard.

[Peter] runs his Ruby web server on a Raspberry Pi, but it should run on any platform that supports Ruby, so you could run it on a NAS device, or pretty much anything that has a web server built in. The Kindle side of the hack exploits some secret commands to disable the screensaver, then uses AJAX and JavaScript to automatically refresh the webpage the RPi is serving.

Hey, why not combine this with the Kindle weather station hack to create a noticeboard that tells you what you need from the store, and reminds you why you shouldn’t leave the house at the same time?

Review: Single Board 65C02 And 65C816 Computers

July 29, 2015 by 51 Comments

The 6502 is a classic piece of computing history. Versions of this CPU were found in everything from the Apple ][, to the Nintendo Entertainment System, and the Commodore 64. The history of the 6502 doesn’t end with video games; for the last forty years, this CPU has found its way into industrial equipment, medical devices, and everything else that doesn’t need to be redesigned every two years. Combine the longevity of the 6502 with the fact an entire generation of developers first cut their teeth on 6502 assembly, and you have the makings of a classic microprocessor that will, I’m sure, still be relevant in another forty years.

The cathedral of The 6502 is Western Design Center. For more than 35 years, WDC has been the home of 6502-related designs. Recently, WDC has been interested in the educational aspects of the 6502, with one of the VPs, [David Cramer], lending his time to an after-school club teaching opcodes.

The folks at WDC recently contacted me to see if I would give their hardware a close look, and after providing a few boards, this hardware proved to be both excellent. They’re great for educators adventurous enough to deviate from the Arduino, Processing, and Fritzing zeitgeist, and for anyone who wants to dip their toes into the world of 65xx development.

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University Peristaltic Pump Has Hacker Heritage

July 29, 2015 by 27 Comments

A team at [Vanderbilt University] have been hacking together their own peristaltic pumps. Peristaltic pumps are used to deliver precise volumes of fluid for research, medical and industrial applications. They’re even occasionally used to dose fish tanks.

pumpThey work by squeezing the fluid in a flexible tube with a series of rollers (check out the awesome gif from Wikipedia to the right). We’ve seen 3D printed peristaltic pumps before, and cheap pumps have been appearing on eBay. But this build is designed to be lab grade, and while the cheap eBay devices can deliver ~20ml/min this one can deliver flow rates in the microliter/min range. It also has a significant cost advantage over commercial research grade pumps which typically cost thousands of dollars, each of these pumps costs only fifty bucks.

The pump has a clear hacker heritage, using an Arduino Uno, Adafruit Motor shield, and 3D printed mechanical parts. So it’s particularly awesome that they’ve also made their design files and Arduino code freely available!

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Say It With Me: Input Impedance

July 29, 2015 by 37 Comments

In the “Say It with Me” series, we’ll take a commonly used concept out of electronics and explain it the best we can. If there’s something that’s been bugging you, or a certain term or concept that keeps cropping up in your projects, let us know. We’ll write about it!

What’s up with input impedance? You hear people talking about it, but why does it matter? And impedance matching? Let’s break it all down.

First of all, impedance is the frequency-dependent sister of resistance, so for intuition we’ll first work through the cases of purely resistive impedance. And that’s almost fine if you’re only ever working at one frequency. We’ll hint at the full-blown impedance = resistance + reactance version at the end, but it’s really its own topic. For now, pretend that your circuits aren’t reactive.

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Teardown Of Intel RealSense Gesture Camera Reveals Projector Details

July 29, 2015 by 23 Comments

[Chipworks] has just released the details on their latest teardown on an Intel RealSense gesture camera that was built into a Lenovo laptop. Teardowns are always interesting (and we suspect that [Chipworks] can’t eat breakfast without tearing it down), but this one reveals some fascinating details on how you build a projector into a module that fits into a laptop bezel. While most structured light projectors use a single, static pattern projected through a mask, this one uses a real projection mechanism to send different patterns that help the device detect gestures faster, all in a mechanism that is thinner than a poker chip.

mechanism1It does this by using an impressive miniaturized projector made of three tiny components: an IR laser, a line lens and a resonant micromirror. The line lens takes the point of light from the IR laser and turns it into a flat horizontal line. This is then bounced off the resonant micromirror, which is twisted by an electrical signal. This micromirror is moved by a torsional drive system, where an electrostatic signal twists the mirror, which is manufactured in a single piece. The system is described in more detail in this PDF of a presentation by the makers, ST Micro. This combination of lens and rapidly moving mirrors creates a pattern of light that is projected, and the reflection is detected by the IR camera on the other side of the module, which is used to create a 3D model that can be used to detect gestures, faces, and other objects. It’s a neat insight into how you can miniaturize things by approaching them in a different way.

Talking, Foot-Pedal-Controlled Bench Probes For VirtualBench

July 29, 2015 by 2 Comments

Developing new products can be challenging during the debug and test phases, often you have your head down trying to probe the lead of some SOT23 transistor, and just when you get it, you scan your eyes up and find that your multimeter is measuring resistance and not voltage.

[Charles] had this issue compounded on his NI Virtual Instrument. It has an interface totally driven from a PC, which may or may not be in a convenient location to mouse around. Luckily NI just released an API for the 5 in one lab test station and [Charles] quickly whipped up a python wrapper which gives him ultimate control over the instrument.

Tying the script to a USB footpedal and adding some text-to-speech capabilities using google’s API [Charles] is easily able to switch from continuity to voltage to resistance and anything else he pleases with just the tap of a foot and listening to the measurements, making sure he never takes his eyes off the work which is risking a short.

Join us after the break for a quick video demonstration.

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The Simplest Steam Engine

July 28, 2015 by 20 Comments

[RimstarOrg] has posted an awesome writeup on his Hero’s steam engine . Hero’s engine is a Greek design from the first century and is the earliest known steam engine. It’s amazing to think he developed the engine seventeen centuries before the industrial revolution, and yet it was largely ignored. While you can find more faithful replicas, of this landmark machine [RimstarOrg]’s rig can’t be beaten for simplicity and he does a great job of explaining the principal of operation and construction.

Using a soda can filled with water and a propane torch [RimstarOrg] was able to get the can to rotate rapidly by ejecting steam from two holes in the side of the can. A fishing swivel is used to provide a pivoting joint and allow the can to rotate freely.

While we’ve covered steam engines before, we loved this simple design, and can’t wait to see what [RimStarOrg] comes up with next.

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