Because Building A Relay Computer Isn’t Hard Enough

April 6, 2018 by Brian Benchoff 28 Comments

For this year’s Hackaday Prize, we’re doing something special. We’re introducing achievements for Prize projects. Think of them as merit badges. If your Hackaday Prize project has multiple parts that come together into one unified, awesome whole, you get the Voltron achievement. If you’ve built a musical instrument that unexpectedly blows everyone’s minds, you get the Diva Plavalaguna Achievement. A select few entries will earn the Pickle Rick achievement. What’s this? It’s a jaw-dropping build that makes you shake your head in the totality of engineering perfection.

Here’s a project that nails this achievement. It’s a homebrew computer, made out of relays, that runs a custom instruction set. It’s built on Brainf*ck. It is, by far, the most absurd and amazing homebrew computer you’ve ever seen.

First, the hardware. This CPU is built out of about 800 Soviet reed relays, RES64, RES55, and RES-43 relays, if you want some part numbers. These relays are mounted on logic cards connected to a backplane. Each backplane consists of thirty-two of these cards, and it takes two backplanes to build up a 16-bit full adder. The 16-bit instruction pointer and 16-bit address pointer each fit on half a backplane.

Moving up one level, the instruction set for this computer is based on Brainf*ck, with a few additions. The ‘+’ instruction adds to the current value, the ‘>’ instruction still increases the current memory address, but there are a few new instructions that make this CPU not an interminable world of suffering. There’s now a ‘write current data value to register’ commands, and logical XOR instructions.

Have relay-based computers been done before? Yes, and so have Brainf*ck ISAs. The combination is rarely seen, and we’ve never seen one that performs this well. Below, you can see a video of this computer counting at 500 operations per second (or 500 Hz from a frequency counter). This is really unimaginable with any other relay computer we’ve seen, and it’s all thanks to those really tiny Soviet tubes. If you want a Hackaday Prize project that’s jaw-dropping, here you go.

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Won’t Somebody, Please, Think Of The Transistors!

April 6, 2018 by Jenny List 146 Comments

At what age did you begin learning about electronics? What was the state of the art available to you at the time and what kinds of things were you building? For each reader these answers can be wildly different. Our technology advances so quickly that each successive generation has a profoundly different learning experience. This makes it really hard to figure out what basic knowledge today will be most useful tomorrow.

Do you know the forward voltage drop of a diode? Of course you do. Somewhere just below 0.7 volts, give or take a few millivolts, of course given that it is a silicon diode. If you send current through a 1N4148, you can be pretty certain that the cathode voltage will be that figure below the anode, every time. You probably also have a working knowledge that a germanium diode or a Schottky diode will have a lower forward voltage, and you’ll know in turn that a bipolar transistor will begin to turn on when the voltage between its base and emitter achieves that value. If you know Ohm’s Law, you can now set up a biasing network and without too many problems construct a transistor amplifier.

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Handheld Arduino Light Painter

April 6, 2018 by Tom Nardi 2 Comments

Light painting is a technique which allows you to “draw” on a photograph by moving a light past the camera during a long exposure shot. While it can be difficult to master, light painting allows for some incredible effects such as text and images that appear to be hovering in mid-air. Think of it like a very slow but much cooler version of an augmented reality app.

[Reven] recently wrote in to tell us about the Arduino light painter he put together, and while DIY (and even commercial) light painting gear isn’t exactly new at this point, we think he’s raised the bar a bit with his design. With the addition of a slick 3D printed enclosure and on-board display and menu system, his light painter looks exceptionally professional for being built out of hardware he had on hand.

On his blog, [Reven] has done a phenomenal job of documenting the build from start to finish. Not only does he include a detailed Bill of Materials and the STL files so you can build your own version of his light painter, he walks the reader though his design process and explains why he did the things he did. Even if you aren’t interested in building a light painter, there’s almost certainly something of interest for anyone who’s ever looked at a pile of parts on their workbench and wondered how they were going to turn it into a functioning device.

Powered by an Arduino Uno, the light painter provides a user interface on a 16×2 LCD which allows control over not only the brightness of the WS2812 LED strips but selecting and loading different images from the micro SD card. The case was designed in FreeCAD, and while [Reven] mentions there are a number of issues which could be improved, satisfies all his design goals.

We covered the original Adafruit project that [Reven] based his code all the way back in 2013, though there’s certainly been more modern interpretations of the idea since then.

Circuit VR: The Dickson Charge Pump

April 6, 2018 by Al Williams 23 Comments

There was a time when taking a low DC voltage — say a single battery — and converting it to a higher voltage was painful. Now, however, cheap and easy-to-use DC to DC converters are readily available. For some small tasks, though, these can seem like overkill. For example, consider a case where you need to supply a higher voltage for a MOSFET gate that doesn’t draw much current. Perhaps you need that higher voltage to trigger a microcontroller’s programming mode and nothing else. The current draw is minimal, and a full-blown DC to DC converter is overkill. For cases like that, it is tempting to use some voltage multiplication scheme. There are many, but for this post, I’m going to take you inside a Dickson charge pump. This is Circuit VR because not only are we going to discuss the circuit, we’ll look at an LT Spice simulation you can try yourself.

The Dickson is interesting because it doesn’t require any AC conversion or transformers. Instead, it uses diodes or other switching elements to transfer charge between capacitors in stages. Each stage will effectively increase the voltage by the supply voltage — in theory. Reality isn’t so kind, though, as we’ll see.

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Monitor Foot Traffic Using Radio

April 6, 2018 by Bryan Cockfield 15 Comments

We talk a lot about information security around here, but in reality it’s not at the forefront of everyone’s minds. Most people are content to walk around with their phones constantly looking for WiFi or Bluetooth connections despite the dangers. But if you’re not a black hat sort of person, you can do something like [Verkehrsrot] did and use all of these phones to do something useful and harmless.

[Verkehrsrot]’s project involves building a radio listening device in order to get an estimate of the amount of traffic in a particular area. The device polls for and detects WiFi and Bluetooth devices nearby and tallies them. For the privacy-minded, it doesn’t persistently store any information about the people or the devices that it detects. The project also runs on a variety of platforms, although you can get the whole thing up and running with little more than an ESP32 and a small lithium-ion battery.

If you’re looking for a useful way to tally the number of people in a given area, this project could be the thing for you. Not everyone keeps their WiFi and Bluetooth turned on, but even so this is still a good way to estimate. But if you need to count everyone going into a room, for example, you’ll need another way to count them.

Firefox Reality, A Browser For VR Devices

April 6, 2018 by Jenny List 31 Comments

The browser you are reading this page in will be an exceptionally powerful piece of software, with features and APIs undreamed of by the developers of its early-1990s ancestors such as NCSA Mosaic. For all that though, it will very probably be visually a descendant of those early browsers, a window for displaying two-dimensional web pages.

Some of this may be about to change, as in recognition of the place virtual reality devices are making for themselves, Mozilla have released Firefox Reality, in their words “a new web browser designed from the ground up for stand-alone virtual and augmented reality headset“. For now it will run on Daydream and GearVR devices as a developer preview, but the intended target for the software is a future generation of hardware that has yet to be released.

Readers with long memories may remember some of the hype surrounding VR in browsers back in the 1990s, when crystal-ball-gazers who’d read about VRML would hail it as the Next Big Thing without pausing to think about whether the devices to back it up were on the market. It could be that this time the hardware will match the expectation, and maybe one day you’ll be walking around the Hackaday WrencherSpace rather than reading this in a browser. See you there!

They’ve released a video preview that disappointingly consists of a 2D browser window in a VR environment. But it’s a start.

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A True 3D Printed Weather Station

April 5, 2018 by Tom Nardi 75 Comments

If the term “3D printed weather station” makes you think of a printed enclosure for off-the-shelf sensors, don’t feel bad. We thought the same thing when we first read the message [Rob Ward] sent in about his latest project. Surely he couldn’t mean that he actually printed all the principal parts of a serious weather station setup, such as the wind vane, anemometer, or rain gauge?

Except, on closer inspection, that’s exactly what he did. Every part of the weather station is designed in OpenSCAD, printed out, and infused with various vitamins to turn them into functional pieces of hardware. Interestingly enough, most of the magic is done with simple reed switches and magnets.

For example, the wind vane uses eight reed switches and an embedded magnet to communicate the current wind direction to the Arduino Uno which handles the user interface. Wind speed, on the other hand, it done with a single reed switch as it just needs to count rotations to calculate speed.

[Rob] did “cheat” by using an off-the-shelf barometric pressure sensor, but we’ll give him a pass for that one. Unless somebody wants to hit the tip line with a design for a printable barometer, we’ll consider this the high water mark in printable weather stations.

This isn’t the first time we’ve seen a DIY anemometer or rain gauge, of varying degrees of complexity. But the clean look of the final version, completely open nature of the OpenSCAD source, and the low part count make this an extremely compelling option for anyone looking to up their home forecasting game.