Air Quality Surveillance for Whole Cities

Air quality is becoming a major issue these days, and not just for cities like Beijing and Los Angeles. It’s important for health, our environment, and our economy no matter where we live. To that end, [Radu] has been working on air quality monitors that will be widely deployed in order to give a high-resolution air quality picture, and he’s starting in his home city of Timisoara, Romania.

[Radu] built a similar device to measure background radiation (a 2014 Hackaday Prize Semifinalist), and another to measure air quality in several ways (a 2015 Hackaday Prize Finalist and a Best Product Finalist; winners will be announced next weekend). He is using the platforms as models for his new meter. The device will use a VOC air sensor and an optical dust sensor in a mobile unit connected to a car to gather data, and from that a heat map of air quality will be generated. There are also sensors for temperature, pressure, humidity, and background radiation. The backbone of the project is a smart phone which will upload the data to a server.

We’ve seen other air quality meters before as well, and even ones based around the Raspberry Pi,  but this one has a much broader range of data that it is acquiring. Its ability to be implemented as an array of sensors to gather data for an entire city is impressive as well. We can envision sensor networks installed on public transportation but to get to all parts of every neighborhood it would be interesting to team up with the Google Streetview Cars, Uber, or UPS. Just Passed 100,000 Members

Today, passed 100,000 registered users. It seems like yesterday that I wrote a post about passing 10k but that was last year already! Much has happened in that year, and there is much more to come. Thank you to everyone that makes great by interacting with each other, posting about what is going on in basements, garages, hackerspaces, and workplaces, and finding new and interesting ways of making the site your very own. Your involvement has made the greatest open source hardware resource in the world.

We don’t call it project hosting. The seed idea did start as project hosting for the hardware hacker, but has long since outgrown that pair of shoes. It’s become a self-sustaining reaction that grows ever bigger and more awesome as everyone gets involved and decides how and what they want to do.

hackchatOne of the major additions to this year was group messaging. This spawned an explosion of new communities within starting with the Hacker Channel. Anyone may request to be a team member and will then gain access to the group messaging; there are now well over 500 members. We’ve scheduled many somewhat-formal events on the channel over the last few months that invited people to show off what they’re building and ask for feedback. That evolved into topic-based sessions on things like FPGA design and what you need to know about manufacturing. Many of these were co-hosted by Hackaday Staff and community members.

This bizarre text is part of the itanimulli profile
This bizarre text is part of the itanimulli profile

A curious event on the site was the appearance of the user itanimulli who join and registered the vanity URL: /conspiracy. This is an enigma. The user is a puzzler and has posted a number of images and other challenges that appear to include hidden data. How do you solve something like this? Get all of your friends involved, of course! Thomas Wilson started a project to solve the itanimulli puzzle and posted about it on the stack to invite teammates to the challenge. has spilled over into the real world too. Do you ever look at the valuable odds and ends in your workshop that you know someone will use, but you never will? The Travelling Hacker Box is the answer to that conundrum. It’s the “take a penny, leave a penny” of the hacker world. Get on the project and get in line to receive the box. When it hits your workshop, take out something cool but then we want to see you build something with it! Replace what you took with something of your own and send it to the next person. International shipping has not been solved yet for this particular box, but nothing is stopping you from starting an EU version.

The support we’ve seen from the hardware community for is one of the reasons we’ve set out to do something new. In just a few weeks the first ever Hackaday SuperConference will be held. Two days of talks and workshops let us meet in person the users we’ve grown close to through the site. I hope to see you there. But if not just ping me on!

Or course 100k isn’t the only interesting number. We’ve got more juicy statistics in the image below.

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You’re Never Too Young to Be a Rocket Scientist

We’ve been keeping tabs on the progress SpaceX has made toward landing a rocket so that it can be reused for future orbital launches. As you would imagine, this is incredibly difficult despite having some of the world’s greatest minds working on the task. To become one of those minds you have to start somewhere. It turns out, high school students can also build guided rockets, as [ArsenioDev] demonstrates in his project on

arseniodev-3d-printed-fin[Arsenio]’s design targets amateur rockets with a fuselage diameter of four inches or so. The main control module is just a cylinder with four servos mounted along the perimeter and some fancy 3D printed fins bolted onto the servo. These are controlled by an Arduino and a 6DOF IMU that’s able to keep the rocket pointing straight up. Staaaay on target.

We saw this project back at the Hackaday DC meetup a month ago, and [Arsenio] was kind enough to give a short lightning talk to the hundred or so people who turned up. You can catch a video of that below, along with one of the videos of his build.

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Laser Rangefinder Brought to Life With Arduino

Range finders are amazing tools for doing pretty much anything involving distance calculations. Want to blink some lights when people are nearby? There’s a rangefinder for that. Need to tell how far away the next peak of a mountain range is? There’s a rangefinder for that. But if you’re new to range finders and want one that’s hackable and configurable, look no further than the SF02/F rangefinder with the Arduino shield, and [Laser Developer]’s dive into what this pair can do.

Once the rangefinder and shield have been paired is when the magic really starts to happen. Using USB, the Arduino can instantly report a huge amount of raw data coming from the rangefinder. From there, [Laser Developer] shows us how to put the device into a “settings” mode which expands the capabilities of the rangefinder even more. The data can be dumped into a graph, for example, which can show trends between distance, laser strength, and many other data sets. [Laser Developer] goes one step further and demonstrates how to use this to calculate the speed of light, but from there pretty much anything else is possible as well.

And while you can just buy a rangefinder off the shelf, they are fairly limiting in their features and can cost exponentially more. This is a great start into using a tool like this, especially if you need specific data or have a unique application. But, if laser range finding isn’t for you or if this project is too expensive, maybe this $5 ultrasonic rangefinder will work better for your application.

Mostly Non-Volatile Memory With Supercapacitors

Back in the days of old, computers used EPROMs to store their most vital data – usually character maps and a BASIC interpreter. The nature of these EPROMs meant you could write to them easily enough, but erasing them meant putting them under an ultraviolet light. Times have changed and now we have EEPROMs, which can be erased electronically, and Flash, the latest and greatest technology that would by any other name be called an EEPROM. [Nicholas] wanted an alternative to these 27xx-series EPROMs, and found his answer in supercapacitors.

[Nick]’s creation is a mostly non-volatile memory built around an old 62256 32k SRAM. SRAM is completely unlike EPROMs or Flash, in that it requires power to keep all its bits in memory. Capacitor technology has improved dramatically since the 1980s, and by using a supercap and one of these RAM chips, [Nick] has created a substitute for a 27-series EPROM that keeps all its memory alive for days at a time.

The circuit requires a small bit of electronics tucked between the EPROM socket and the SRAM chip; just enough to turn the 12 Volts coming from the EPROM programming pin to the 5 Volts expected from the SRAM’s Write Enable pin. This is accomplished by a few LEDs in series, and a 0.1F 5.5V supercap which keeps the SRAM alive when the power is off.

As for why anyone would want to do this when modern technologies like Flash can be found, we can think of two reasons. For strange EPROM sizes, old SRAMs abound, but a suitable Flash chip in the right package (and the right voltage) might be very hard to find. Also, EEPROMs have a write lifetime; SRAMs can be written to an infinite number of times. It’s not the best solution in every case, but it is certainly interesting, and could be useful for more than a few vintage computing enthusiasts.

This project makes us think of another where an LED may have been supplying keep-alive power to some volatile memory.

Hacklet 79 – USB Projects

Universal Serial Bus was created to simplify interconnecting computers and peripherals. First released in 1996, hackers and makers were slow to accept this strange new protocol. Parallel and serial ports were simpler, worked great, and had decades of hacking with thousands of projects behind them. As the new standard caught on in the mainstream, RS-232 and parallel ports started disappearing. “Legacy free” PC’s became the norm. Hackers, Makers, and Engineers had no choice but to jump on the bandwagon, which they did with great gusto. Today everything has a USB port. From 8 bit microcontrollers to cell phones to children’s toys. This week’s Hacklet is about some of the best USB projects on!

two partsWe start with [Michael Mogenson] and Two Component USB Temperature Data Logger, which may be the simplest USB device ever made. [Michael] isn’t kidding. This data logger consists of just a Microchip PIC16F1455 microcontroller and a USB connector. Microchip’s datasheet calls for a capacitor to smooth out power, but [Michael] made it work without the extra part. He used M-Stack by Signal 11 to implement the USB stack. Once connected to a PC, the PIC enumerates as a serial port device. It then sends its die temperature of the PIC once per second. It could do more, but that would probably require adding a few more components!

tester1Next up is [davedarko] with USB cable tester. Dave recently spent some time installing USB RFID readers. These devices were only a few meters away from the computer controlling them. Even so, the power and USB data cables had to run through pipes and in some cases under water. It wasn’t fun troubleshooting a device to find that it was a shorted USB cable causing the problem. [Dave’s] solution is a tiny coin cell powered board that tests each of the 4 wires in a standard USB 2.0 cable. The board runs on an ATtiny45 microcontroller. [Dave’s] current iteration has footprints for mini and micro USB connectors, along with the standard USB-A.


tester2[MobileWill] has a USB Tester of his own. This USB tester checks current consumption and rail voltage. It does this by connecting in-line with the device under test. It’s perfect for troubleshooting why your PC’s USB port goes into over-current protection every time you plug in your device. The tester is modular – you can use the base board with your own multimeter, or grab [Will’s] tester backpack and see the results right on the built-in OLED display. USB Tester is [Will’s] entry in the 2015 Hackaday Prize.


tbdFinally, we have [ajlitt] with Tiny Bit Dingus (TBD). TBD is a USB interface to 6 wires. Think of it as a tiny version of the bus pirate. This lilliputian board holds a Freescale KL27Z ARM processor, which has more than enough power to handle things like I2C, SPI, PWM, or just about any other way to send data or wiggle wires. [Ajlitt] started this project as an excuse to learn KiCAD and gain some experience with surface mount solder stencils. The result is an absolutely tiny board that is all but lost in a USB socket. Programming is handled with the mbed library, though you can always use Freescale’s native tools. Flashing code on the TBD is easy with kut, a chrome browser plugin.

If you want to see more USB projects, check out our new USB projects list. Did I miss your project? Don’t be shy, just drop me a message on That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of!

Juggling Robot Deftly Handles Balls

A well-designed robot can do any action a human can do. Whether this is an acrobatic performance, or just writing with a pen, there’s a robot out there for any single action a human can perform. This includes juggling, but never before has the human action of juggling been replicated at this scale. [Nathan] built a robot that can juggle seven balls simultaneously. That’s more balls in the air than any other juggling robot.

jugglebotWhile the original plan was to build a low-cost version that could juggle balls by throwing them up in the air, this proved to be very difficult. Instead of giving up, [Nathan] simplified the problem by rolling the balls up a ramp. The entire build is documented in an imgur gallery, and there’s some interesting tech going on here. The 3D printed arms are controlled by beefy stepper motors running at 60V. To stop the balls from bouncing around in the arms, [Nathan] included and electromagnet to hold the balls in place for a fraction of a second during each cycle.

Juggling seven balls is amazing, but how about eight? This is the question every builder of a juggling robot will get, and it’s not quite as simple as adding another ball. The motion of juggling an even number of balls is completely different from juggling an odd number. That being said, [Nathan]’s robot does have four balls under its belt. It should probably get that looked at.

This isn’t [Nathan]’s first amazing 3D printed robot, and it probably won’t be the last, either: he recently built a Skittles sorting machine for the next time Van Halen comes to town. There’s an amazing amount of skill in all his projects, and he’s certainly an asset to the entire community.

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