Resource monitoring solution

Electricity, Gas and Water – three resources that are vital in our daily lives. Monitoring them using modern technology helps with conservation, but the real impact comes when we use the available data to reduce wasteful usage over time. [Sébastien] was rather embarrassed when a problem was detected in his boiler only during its annual inspection. Investigations showed that the problem occurred 4 months earlier, resulting in a net loss of more than 450 cubic meters, equivalent to 3750 liters per day (about 25 baths every day!). Being a self professed geek, living in a modern “connected” home, it rankled him to the core. What resulted was S-Energy – an energy resource monitoring solution (translated) that checks on electricity, gas and water consumption using a Raspberry Pi, an Arduino, some other bits of hardware and some smart software.

[Sébastien] wanted a system that would warn of abnormal consumption and encourage his household folks to consume less. His first hurdle was the meters themselves. All three utilities used pretty old technology, and the meters did not have pulse data output that is commonplace in modern metering. He could have replaced the old meters, but that was going to cost him a lot of money. reflective-power-meter-sensorSo he figured out a way to extract data from the existing meters. For the Electricity meter, he thought of using current clamps, but punted that idea considering them to be suited more for instantaneous readings and prone for significant drift when measuring cumulative consumption. Eventually, he hit upon a pretty neat hack. He took a slot type opto coupler, cut it in half, and used it as a retro-reflective sensor that detected the black band on the spinning disk of the old electro-mechanical meter. Each turn of the disk corresponds to 4 Watt-hours. A little computation, and he’s able to deduce Watt-hours and Amps used. The sensor is hooked up to an Arduino Pro-mini which then sends the data via a nRF24L01+ module to the main circuit located inside his house. The electronics are housed in a small enclosure, and the opto-sensor looks just taped to the meter. He has a nice tip on aligning the infra-red opto-sensor – use a camera to check it (a phone camera can work well).

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MRRF: Hot Ends, Extruders, Extremely Posh Brits, and Stoic Swedes

As far as locations for the Midwest RepRap Festival go, it’s not exactly ideal. This is a feature, not a bug, and it means only the cool people come out to the event. There were a few people travelling thousands of miles across an ocean, just to show off some cool things they built.

Two Colors, One Nozzle

[Sanjay] and [Josh] from E3D came all the way from merry olde England to show off a few of their wares. The star of their show was the Cyclops extruder, a dual-extrusion hot end that’s two input, one output. Yes, two colors can come out of one nozzle.

cyclops

If you see a printer advertised as being dual extrusion, what you’re going to get is two extruders and two hot ends. This is the kludgy way to do things – the elegant solution is to make two colors come out of one nozzle.

The guys from E3D were showing off a few prints from their Cyclops nozzle that does just that, including a black and red poison dart frog, and a blue and white octopus. The prints looked amazing, and exactly what you would expect from a two-color print.

Rumor has it the development of the Cyclops involved extruding two colors, freezing the nozzle, and putting it in the mill just to see how the colors mixed. I didn’t see those pictures, but there’s a lot of work that went into this hot end.

The Power of Two Extruders

[Martin] of bondtech.se came to MRRF all the way from Sweden. He was there showing off his new extruder.

The extruder uses a normal stepper motor, but instead of the usual knurled or threaded feed wheel and bearing to push filament though, he’s using two counter-rotating feed wheels attached to a planetary gear system. That’s a lot of torque that doesn’t distort or strip the filament. When you consider all the weird filaments that are coming out – ninjaflex, and even 3D printable machinable wax filament, this is extremely interesting.

Even if your filament isn’t exactly 1.75 or 3mm in diameter, this setup will still reliably push plastic; there is a bolt that will move one of the feed wheels in and out 0.4mm.

[Martin] had a pair of his extruders hooked up to a strain gauge, and it’s strong enough to lift your printer off the table without stripping the filament. Here’s a video of that demo from the bondtech page.

Mustachioed Nintendo Virtual Boy Gone Augmented Reality

Some people just want to watch the world burn. Others want to spread peace, joy and mustaches. [Joe Grand] falls into the latter group this time around. His latest creation is Mustache Mayhem, a hack, video game, and art project all rolled into one. This is a bit of a change from deconstructing circuit boards or designing electronic badges, but not completely new for [Joe], who wrote SCSIcide and Ultra SCSIcide for the Atari 2600 back in the early 2000’s.

Mustache Mayhem is built into a Nintendo Virtual Boy housing. The Virtual Boy itself was broken, and unfortunately was beyond repair. [Joe] removed most of the stock electronics and added a BeagleBone Black, Logitech C920 webcam, an LCD screen and some custom electronics. He kept the original audio amplifier, speakers, and controller connector. Angstrom Linux boots into [Joe’s] software, which uses OpenCV to detect faces and overlay mustaches. Gameplay is simple: Point the console at one or more faces. If you see a mustache, press the A button on the controller! The more faces and mustaches on-screen at once, the more points, or “mojo” the player gets. The code is up on Github, and can be built with Xcode targeted to the Mac, or directly on the BeagleBone Black.

[Joe’s] goal for the project was to make a ridiculous game that looks like it could have come out in the 90’s. He also used Mustache Mayhem as a fun way to learn some new skills which will come in handy for more serious projects in the future.

We caught up with [Joe] for a quick interview about his new creation.

How did you come up with the idea for Mustache Mayhem?

blockI was selling a bunch of my video game collection at PRGE (Portland Retro Gaming Expo) a few years ago and had a broken Virtual Boy that no one bought. A friend of mine was at the table and said I had to do something with it. I thought “People wear cosplay and walk around at conventions, so what if I could do something with the Virtual Boy that you could walk around with?” That was the seed.

A few months later, Texas Instruments sent me the original production release of the BeagleBone Black (rev. A5A). Eighteen months after that I actually started the project. The catalyst was to do something for an upcoming Portland, OR art show (Byte Me 4.0), which is an annual event that shows off interactive technology-based artwork. I wrote up a little description and got accepted. I had less than 2 months to actually get things working and it ended up taking about a month of full-time work. It was much more work than I expected for such a silly project. I originally was going to do something along the lines of walking around in a Doom-like perspective and shooting people when their faces were detected.

That would be pretty darn cool. How did you get from Doom to Mustaches? 

I saw a TI BeagleBoard demo called “boothstache” which drew mustaches on faces and tweeted the pictures. I thought that doing something non-violent with mustaches would be more suitable (and funny) to actually show my kids. I also secretly wanted to use this project as a way to experiment with Linux, write some code, and learn about face detection and image processing with OpenCV, which I plan to use for some actual computer security research in the future. Mustache Mayhem turned out to be a super cool project and I’m really happy with it. I sort of feel guilty spending so much time on it, since it’s basically just a one-off prototype, but I just got so obsessed with making it exactly as I wanted.

You mentioned on your website that Mustache was “designed to challenge the paradigms of personal privacy and entertainment.” What exactly did you mean there?

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Logic Noise: Filters and Drums

Filters and Drums

Logic Noise is an exploration of building raw synthesizers with CMOS logic chips. This session, we continue to abuse the 4069UB as an amplifier. We’ll turn the simple unity-gain buffer of last session into a single-pole active lowpass filter with a single part. (Spoiler: it’s a capacitor.)

While totally useful, this simple filter is a bit boring and difficult to make dynamic. So we’ll look into an entirely different filter, the Twin-T notch filter, that turns out to be sharp enough to build a sine-wave oscillator on, and tweakable enough that we’ll make a damped-oscillator drum sound out of it.

Here’s a quick demo of where we’re heading. Read on to see how we get there.

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Prove Your Design; Prove Your Market; Earn Six-Digits of Cash

Let’s talk about the newest part of this year’s Hackaday Prize: Best Product. In addition to all of the other prizes offered, the Best Product Prize will award $100,000 to one entry which is designed for manufacturing and embodies the core of this year’s theme. What exactly does that mean? It boils down to one hundred grand to jumpstart your product launch. Let’s take a closer look at why we added this prize and the specifics of entry.

What about the other 90%

You have a working prototype and you’re one step away from making your first million, right? That is almost always a fallacy. One major hurdle is the engineering needed to take a working prototype to the factory line — that can be nine-tenths of the work. Designing for production is a story that we want to tell. This becomes an educational tool for those just starting to learn about product design. If we make the steps, gotchas, and tricks of the trade easier to learn we chip away at the hard part of hardware and this is one of the chief motivators for adding Best Product.

Proving Your Market

Before you take the risk you want to make sure there is a customer base out there who want to buy your hardware. We’ve noticed that Crowd Funding platforms are a growing avenue for market research. It has become something of a pre-order system, but it also means that all decisions are somewhat locked in before going into production. We see the Best Product prize as a way to prove the market, not just for the winner but surely for all of the ten finalists as well. Still want to go the crowd funding route afterwards? Fine, we’ve seen big things happen for a lot of great builds featured on Hackaday. But competing for the Best Product award keeps your options open during and after the crowd has spoken their peace.

Slightly Different Entry and Judging Criteria

best-product-requirementsThe entry requirements and judging criteria for Best Product are both a bit different form the main entry field. Rest assured you are still eligible to compete for all of the other prizes.

On the entry side of things the biggest difference is that you need to send us three working beta units for testing by August 17th. When we sat down to figure out what makes something “a product”, the existence of several working prototypes in the hands of beta users was high on that list. In this case we’ll be the testers but this lets us verify that entries aren’t vaporware. You will also need to complete most of your documentation by the entry date.

On the judging side of things the criteria quite different. One noteworthy change to point out; Openness is not among the Best Product judging criteria. If you want to keep the secret-sauce secret you won’t be penalized for it. However, if you also want to win the Grand Prize, Open is the way.

Read the Rules, Start Your Entry

Now that you’re really excited about all of this, make sure you go and read all of the Official Rules. Sections 4 & 5 both have information about Best Product entry and judging criteria.

Getting your entry started is easy. Just begin a project on Hackaday.io and add the tags “2015HackadayPrize” and “BestProduct”. This lets us know you’re in it to win it and we’ll keep you informed of what is coming down the pipeline as the Hackaday Prize progresses.


The 2015 Hackaday Prize is sponsored by:

Playing Space Invaders with Real Fire and Lasers

Making a Space Invaders game is up there on the list of most unconventional things you could do with a laser cutter. In watching the tiny little ships burst into flames, [Martin Raynsford’s] modification has got to be one of the more dangerous looking ones we’ve seen as well.

[Martin] always had the desire to make a tangible version of the classic game. Since his Whitetooth A1 laser cutter already contained the bulk of the moving hardware needed, not to mention an actual high powered laser to “pew pew” with, he decided it was the perfect starting point for such a project. The game is played looking down into the cutter since the laser of course fires in that direction, however a basic webcam is mounted to the laser assembly so that you can view the game on a computer screen at the proper perspective. An Arduino Mini is responsible for stepper control, allowing the player to jog back and forth and fire with a keyboard. [Martin] added an extra gear to the z-axis bed-leveler so that it could drive rows of paper invaders left and right across the bottom. Paperclips wedged into slots along a modified backboard hold each of the paper slips in place. This works ideally since they can be reloaded easily and won’t be maimed during use.

Due to the heat of the laser, landing a well positioned shot will likely nuke all of the nearby invaders as well, making for a theatrical inferno and easy win. Now to step up the difficulty level and figure out how to make them fire back…

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AVR Hardware Timer Tricked Into One-Shot

[Josh] has written up two posts that those of you who use AVRs might find handy. The first post documents a C library that implements a jitter-free one-shot timer. The second post explains how it works. We think it’s such a good idea that we’re going to spoil it for you, but go ahead and read his links and check out his code.

A one-shot is a pulse generator that runs once and only once. You trigger it, it produces the desired pulse, and that’s all she wrote. Why is this handy? Many external ICs that you’ll interface with have minimum durations for signal pulses that must be respected. You could program the AVR to toggle a pin high and then sit around and wait until it’s time to toggle the pin low again, but this wastes valuable CPU time, isn’t going to be very precise, and is susceptible to timing discrepancies if interrupt routines fire in the mean time.

You’d think that you could use the hardware timers for this, but it’s not straightforward. Normally, the timers are free-running; the counter that’s keeping track of time rolls over the top and starts over again. But we just want one pulse.

[Josh]’s very clever idea abuses the timer/counter’s TOP and MATCH values in “Fast PWM” mode. Essentially you trick the counter into never matching by setting TOP below MATCH. This means that the counter spins in its loop between zero and TOP forever, doing nothing.

To break it out of its loop and enable the one-shot, you manually set the counter to a value above TOP and let it go. As it counts up, it’ll eventually hit MATCH, turn on your pin, and then keep counting. When it rolls over the top (255 + 1 = 0 for the 8-bit AVRs), your pin will be correctly turned off again and then the counter re-enters its loop. The one-shot won’t fire until you manually set the counter higher than TOP again.

So there you have it, a one-shot depending only on the hardware timer/counter module and thus immune to jitter and consuming no CPU time at all. Our hats off to you, [Josh]. Clever hack.