A Portable, Accurate, Low-Cost, Open Source Air Particle Counter

If you live in a city with poor air quality you may be aware that particulates are one of the chief contributors to the problem. Tiny particles of soot from combustion, less than 10μm across, hence commonly referred to as PM10. These are hazardous because they can accumulate deep in the lungs, wherein all kinds of nasties can be caused.

There are commercial sensors available to detect and quantify these particles, but they are neither inexpensive nor open source. [Rundong] tells us about a project that aims to change that situation, the MyPart, which is described as a portable, accurate, low-cost, open source air particle counter. There is a GitHub repository for the project as well as a series of Instructables covering the build in detail. It comes from a team of members of the Hybrid Ecologies Lab at UC Berkeley, USA.

Along the way, they provide a fascinating description of how a particulate sensor works. A laser shines at right angles across a photodiode, and is brought to a focal point above it. Any particulates in the air will scatter light in the direction of the photodiode, which can thus detect them. The design of a successful such sensor requires a completely light-proof chamber carefully built to ensure a laminar flow of air past laser and diode. To that end, their chamber has several layers and is machined rather than 3D-printed for internal smoothness.

We’ve covered quite a few environmental sensors over the years here at Hackaday. An open source volatile organic compound (VOC) detector featured last year for example, or this Raspberry Pi-based  system using a commercial gas sensor.

Super-Sizing Leaf Collection; Hackers Doing Yardwork

For many parts of the world, the great raking has begun as deciduous trees in temperate zones drop their leaves. Of course not everyone can abide the simple yet laborious process of manual raking and so they look to technology. You can buy a handheld leaf vacuum, a pull-behind leaf sweeper, or a mower attachment that lifts leaves into hoppers. [Lou] has the latter, but it’s way too small for his taste so he super-sized his leaf collecting hardware.

The hard part of leaf collection has already been solved for [Lou]. The riding lawnmower lifts the leaves and propels them through an angled pipe into three hopper bags which we think total 9 bushels (roughly 80 gallons or 300 liters). That sounds like a lot, but anyone who has recently cleared leaves will attest that they will fill up in no time.

[Lou] builds a light-weigh 4-foot cube covered in deer netting to super-size his hopper to a whopping 51 bushels (475 gallons or 1800 liters)! His first attempt uses a pipe that falls too short to fill leaves to the top, but his final product adds longer ductwork and hits the mark perfectly.

Gardeners everywhere should be salivating right now. Leaf mulch is one of the best things you can put on your garden in the spring. Although [Lou] designed his hopper to be emptied by leaf-blower, adapting this to set the full hopper in an out-of-the-way space would help them breakdown over the winter — turning them into planter’s gold by springtime.

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Hackaday Links: November 13, 2016

The Travelling Hackerbox is going International. I wrote a post on this earlier in the week, and I’m still looking for recipients for the box that are not in the United States. The sign-up form is right here, [the sign up form is now closed] and so far we have good coverage in Canada, Australia, NZ, Northern Europe, and a few in Africa. If you ever want to be part of the Travelling Hackerbox, this is your chance. I’m going to close the sign-up sheet next week. Sign up now.

Like the idea of a travelling hackerbox, but are too impatient? Adafruit now has a box subscription service. Every quarter, an AdaBox will arrive on your doorstep packed to the gills with electronic goodies.

The very recently released NES Classic edition is the 2016 version of the C64 DTV — it’s a Linux system, not as elegant, and there’s little hacking potential. If you want to increase the amount of storage, desolder the Flash chip (part no. S34ML04G200TFI000), and replace it with a larger chip. The NES Classic edition isn’t the coolest retro system coming out — Genesis is back, baby. Brazil has had a love affair with the Genesis/Mega Drive because of their bizarre import restrictions. Now, the manufacturer of the Brazilian Sega clones is releasing a Linux-ified clone. Does anyone know how to export electronics from Brazil?

The CFP deadline for the SoCal Linux Expo is fast approaching. You have until the 15th to get your talks in for SCALE.

Let’s talk about dissolvable 3D printer support material. One of the first materials able to be printed and removed by dissolving in water was PVA. Makerbot sold it for use in their dual extruder machines. PVA does dissolve, but it degrades at higher temperatures and kills nozzles. HIPS can be dissolved with limonene, but it’s really only for use in conjunction with ABS. This week, E3D released their Scaffold support material. It’s a PVA/Polyvinyl alcohol filament — ‘the stuff gel caps are made out of’ was the line we got when E3D previewed Scaffold at MRRF last March. It’s a support material that’s water dissolvable, compatible with most filaments, and is able to produce some amazing prints. It’s available now, but it is a bit pricey at £45 for half a kilo. Brexit is a good thing if you’re paid in dollars.

If you’re into chiptunes, you’ve heard about Little Sound DJ. LSDJ is a cart/ROM capable of toggling all the registers on the Game Boy sound chip, sequencing bleeps and bloops, and generally being awesome. The recently released Nanoloop Mono is not Game Boy software. It’s a few op-amps and a PIC micro pasted on a board that turns the Game Boy into a synth. You get a significantly more 80s sound with the Nanoloop Mono over LSDJ, audio input, and a step sequencer.

A Truly Classy Metal-Framed Mini CNC

We’ve seen a number of DVD- and CDROM-based small CNC machines here, but few are as simply beautiful as this one by [julioberaldi] over on Instructables (translated from Portuguese here).

fbis2gciv0ajsdxWe’ll cut to the chase; it’s the frame. Cut from steel sheet scraps with a hacksaw, and welded or soldered together with “bar solder”. It looks like a lot of sanding, painting, and polishing went on. The result is something we’d be proud to have on our desk.

For now, it simply draws with a pen. But watch the video, embedded below, and you’ll see that it runs exceptionally smoothly. If we’re reading the Instructable right, the next step is to turn this into a CNC cutter. We can’t wait to see where the project goes from here.

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Linux On Your NES Classic Edition

Nintendo look as though they may have something of a hit on their hands with their latest console offering. It’s not the next in the line of high-end consoles with immersive VR or silicon that wouldn’t have looked out of place in last year’s supercomputer, instead it’s an homage to one of their past greats. The NES Classic Edition is a reboot of the 1980s console with the familiar styling albeit a bit smaller, and 30 of the best NES games included.

You do not, however, get an original NES with a 6502 derived processor, and a stack of game cartridges. In the Classic Edition is a modern emulator, running on very modern hardware. We’re told it contains an Allwinner R16 quad-core Cortex A7 SoC, 256Mb of RAM, and 512Mb of Flash. That’s a capable system, and unsurprisingly any hacking potential it may have has attracted some interest. Reddit user [freenesclassic] for example has been investigating its potential as a Linux machine, and has put up a post showing the progress so far. It is known that there is already some form of Linux underpinning the console because Nintendo have released a set of sources as part of their compliance with the terms of the relevant open-source licences. That and the availability of a serial port via pads on the PCB gives hope that a more open distro can be installed on it.

We’re taken through the process of starting the machine up with the serial port connected to a PC, and getting it into the Allwinner FEL mode for low-level flashing work. Then we’re shown the process of loading a custom U-Boot, from which in theory a kernel of your choice can be loaded.

Of course, it’s not quite that simple. There is still some way to go before the device’s Flash can be accessed so for now, all that is possible is to use the RAM, and the current state of play has a kernel panic as it is unable to mount a filesystem. However this is a new piece of hardware in its first few days after launch, so this is very much a work in progress. We are sure that this device will in time be opened up as a fully hackable piece of hardware, and we look forward to covering the interesting things people do with it when that has happened.

If you are interested in the NES Classic, take a look at it on Nintendo’s web site. Meanwhile, here at Hackaday as a quick look at our past stories tagged “nes” shows, we’ve covered a huge number of projects involving the platform in the past.

Thanks [Doc Oct] for the tip.

Original NES console header image: Evan-Amos [Public domain], via Wikimedia Commons.

PLC and Linear Actuators Automate Double-Hung Windows

Very few residential architectural elements lend themselves to automation, with doors and windows being particularly thorny problems. You can buy powered doors and windows, true, but you’ll pay a pretty penny and have to go through an expensive remodeling project to install them. Solving this problem is why this double-hung window automation project caught our eye.

Another reason we took an interest in this project is that [deeewhite] chose to use a PLC to control his windows. We don’t see much love for industrial automation controllers around here, what with the space awash in cheap and easy to use microcontrollers. They have their place, though, and a project like this is a good application for a PLC. But the controller doesn’t matter at all if you can’t move the window, for which task [deeewhite] chose 12V linear actuators. The fact that the actuators are mounted in the center of the window is probably necessary given the tendency of sashes to rack in their frames and jam; unfortunately, this makes for a somewhat unsightly presentation. [deeewhite] also provides the ladder logic for his PLC and discusses how he interfaces his system with Alexa, a WeMo and IFTT.

We’d love to see this project carried forward a bit with actuators hidden under the window trim, or a rack and pinion system built into the window tracks themselves. This is a pretty good start and should inspire work on other styles of windows. While you’re at it, don’t forget to automate the window blinds.

[via r/DIY]

Pulling Music Out Of The Airwaves

RADIO WONDERLAND is a one-man band with many famous unintentional collaborators. [Joshua Fried]’s shows start off with him walking in carrying a boombox playing FM radio. He plugs it into his sound rig, tunes around a while, and collects some samples. Magic happens, he turns an ancient Buick steering wheel, and music emerges from the resampled radio cacophony.

It’s experimental music, which is secret art-scene-insider code for “you might not like it”, but we love the hacking. In addition to the above-mentioned steering wheel, he also plays a rack of shoes with drumsticks. If we had to guess, we’d say rotary encoders and piezos. All of this is just input for his computer programs which take care of the sampling, chopping, and slicing of live radio into dance music. It’s good enough that he’s opened for [They Might Be Giants].

Check out the videos (embedded below) for a taste of what a live show was like. There are definitely parts where the show is a little slow, but they make it seem cooler when a beat comes together out of found Huey Lewis. We especially like the “re-esser” routine that hones in on the hissier parts of speech to turn them into cymbals. And if you scan the crowd in the beginning, you can find a ten-years-younger [Limor Fried] and [Phil Torrone].

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