Petite Package Provides Powerful Robot

The Robot Operating System (ROS) is typically associated with big robots but [Grassjelly] decided to prove differently by creating Linorobot. This small, differential drive robot is similar in appearance to many small Arduino based robots often used for line following. Linorobot packs a lot more computing power with a Teensy 3.1 connected to a Radxa Rock Pro. The Teensy handles the motors, reading their encoders, and acquisition of IMU data.

The Radxa, new to us here at Hackaday, is a single board computer based on the quad-core ARM Cortex-A9 1.6 GHz CPU. It may not have been seen on our pages but if you’re at Hackaday Belgrade you can attend a session on building a cluster using it. The ability to run Linux is key to using ROS, which is an open source system for controlling robots. With the Radxa running ROS it interfaces directly to the Neato XV-11 Lidar’s dedicated controller board.

The Linorobot packs into a small robot the capabilities usually seen in much larger and expensive robots such as the Turtlebot 2. With this diminutive robot hackers can learn about doing SLAM (Simultaneous Localization and Mapping) and autonomous navigation, plus the other capabilities of ROS.

[Grassjelly] has a tutorial on building the robot which is also a good introduce to ROS. He provides the software as open source. It’s an impressive project which provides a small, comparatively affordable robot for learning and working with ROS. A video of Linorobot SLAMing and navigating [Grassjelly’s] lab is after the break.

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EKG Business Card Warms Our Hearts

Giving out a paper business card is so 1960s. Giving out a PCB business card, well that gets you up to the early 2010s. If you really want to stand out these days, give them a fully-functional EKG in a business card. (Note: works best if you’re leading an open-source electrocardiography project.)

Looking through the schematics (PDF), there’s not much to the card. At the center of everything is an ADuC7061, which is an ARM microprocessor equipped with 24-bit ADCs that also has an internal DAC-driven voltage reference connected to one of the user’s thumbs. This, plus a little buffering circuitry, seems to be enough to translate the tiny voltage potential difference across your two hands into a beautiful signal on the included OLED display. Very nice!

Everything (including the big version of their EKG) is open source and made on an open toolchain. If you’re interested in health and medical sensing, you should head over to the project’s GitHub and check it out. The standalone open EKG is based on a much more complicated circuit, and stands to be more accurate. But the business card version is just soooo cute!

Thanks [Ag Primatic] for the tip!

Hackaday Links: March 13, 2016

Way back in 2014, Heathkit was a mystery. We knew someone was trying to revive the brand, but that was about it. Adafruit pulled out all the stops to solve this mystery and came up with nothing. The only clue to the existence of Heathkit was a random person who found a geocache in Brooklyn Bridge Park. Since then, Heathkit has released an odd AM radio kit and $150 antenna. These offerings only present more mysteries, but at least [Paul] was finally rewarded for finding the Heathkit geocache. Heathkit sent [Paul] the AM radio kit. He says it’s neat and well documented.

[David] is doing his masters thesis on, “The motivation of the maker community”. That means empirical data, and that (usually) means surveymonkey. You can take his survey on the motivations of the maker community here.

America’s best loved companies, Verizon and Makerbot, together at last.

The BeagleBone Black was launched in 2013. The BeagleBone Green – a Seeed joint – showed up last August. The BeagleBone Blue, released just a few months ago, is a collaboration between the UCSD engineering department and TI. Now there’s the BeagleBone Enhanced. Yes, they should have picked another color. Perhaps ecru. The BB Enhanced sports one Gigabyte of RAM, Gigabit Ethernet, two USB ports and two USBs via an expansion header, optional serial NOR Flash for a bootloader, optional six-axis gyro, and optional barometer.

Atmel is changing a few AVRs. There is a new die for the ATMega 44, 88, 168, and the ‘Arduino chip’, the ATMega328. Most of the changes are relatively inconsequential – slightly higher current consumption in power save mode – but one of these changes is going to trip up a lot of people. The Device ID, also known as the source of the avrdude: initialization failed, rc=-1 error, has changed on a lot of chips.

Makeit Labs in Nashua, New Hampshire has a problem. They were awarded $250,000 in tax credits to help them move and renovate. Sounds like a very good problem, right? Not so: they need to sell these tax credits before the end of the month, or they lose them. They’re looking for a few businesses in New Hampshire to buy these tax credits. From [Peter Walsh]: “Under the credit program, a typical business donating $10,000 would save $9,000 on their state and federal taxes! That $10,000 donation would cost them only $1006!” Does that make sense? No, it’s taxes, of course not. If you’re a business in New Hampshire and are looking to reduce your tax burden, this is the solution.

So I mentioned MRRF, right? You should go to MRRF. It’s next weekend.

A Pi Powered Recording Studio

In the mid-90s, you recorded your band’s demo on a Tascam cassette tape deck. These surprisingly cheap four-track portable studios were just low tech enough to lend an air of authenticity to a band that calls itself, ‘something like Pearl Jam, but with a piano’. These tape decks disappeared a decade later, just like your dreams of being a rock star, replaced with portable digital recording studios.

The Raspberry Pi exists, the Linux audio stack is in much better shape than it was ten years ago, and now it’s possible to build your own standalone recording studio. That’s exactly what [Daniel] is doing for our Raspberry Pi Zero contest, and somewhat predictably he’s calling it the piStudio.

Although the technology has moved from cassette tapes to CompactFlash cards to hard drives, the design of these four-track mini recording studios hasn’t really changed since their introduction in the 1980s. There are four channels, each with a fader, balance, EQ, and a line in and XLR jack. There are master controls, a few VU meters, and if the technology is digital, a pair of MIDI jacks. Since [Daniel] is using a Raspberry Pi for this project, he threw in an LCD for a great user interface.

As with all digital recorders, the money is in the analog to digital converters. [Daniel] is using a 24-bit, 216kHz, four-channel chip, Texas Instruments’ PCM4204. That’s more than enough to confuse the ears of an audiophile, although that much data will require a hard drive. Good thing there will be SATA.

Although you can buy an eight-channel solid state recorder for a few hundred dollars – and [Daniel] will assuredly put more than that into this project, it’s a great application of a ubiquitous Linux computer for a device that’s very, very useful.


The Raspberry Pi Zero contest is presented by Hackaday and Adafruit. Prizes include Raspberry Pi Zeros from Adafruit and gift cards to The Hackaday Store!
See All the Entries || Enter Your Project Now!

Blinky LED Bike Bag

Bicycle riders can never be too visible: the more visible you are, the less chance there is someone will hit you. That’s the idea behind the Arduibag, a neat open-source project from [Michaël D’Auria] and [Stéphane De Graeve]. The project combines a joystick that mounts on the handlebars with a dot matrix LED display in a backpack. By moving the joystick, the user can indicate things such as that they are turning, stopping, say thank you or show a hazard triangle to warn of an accident.

The whole project is built from simple components, such as an Adafruit LED matrix and a Bluno (an Arduino-compatible board with built-in Bluetooth 4.0) combined with a big battery that drives the LED matrix. This connects to the joystick, which is in a 3D printed case that clips onto the handlebars for easy use. It looks like a fairly simple build, with the larger components being mounted on a board that fits into the backpack and holds everything in place. You then add a clear plastic cover to part of the backpack over the LED matrix, and you are ready to hit the road, hopefully without actually hitting the road.

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Machine Shop Soaps Are Good, Clean Learning Fun

At first glance, it’s easy to dismiss the creation of custom bath soaps as far outside the usual Hackaday subject matter, and we fully expect a torrent of “not a hack” derision in the comments. But to be able to build something from nothing, a hacker needs to be able to learn something from nothing, and there is plenty to learn from this hack.

On the face of it, [Gord] is just making kitschy custom bath soaps for branding and promotion. Cool soaps, to be sure, and the drop or two of motor oil and cutting fluid added to each batch give them a little machine shop flair. [Gord] experimented with different dyes and additives over multiple batches to come up with a soap that looked like machined aluminum; it turns out, though, that adding actual aluminum to a mixture containing lye is not a good idea. Inadvertent chemical reactions excepted, [Gord]’s soaps and custom wrappers came out great.

So where’s the hack? In stepping way outside his comfort zone of machining and metalwork, [Gord] exposed himself to new materials, new techniques, and new failure modes. He taught himself the basics of mold making and casting, how to deal with ultra-soft materials, the chemistry of the soap-making process, working out packaging and labeling issues, and how to deal with the problems that come from scaling up from prototype to production. It may have been “just soap”, but hacks favor the prepared mind.

Birthday Celebrations The Pi Way

The William Gates Building concourse packed with Pi enthusiasts
The William Gates Building concourse packed with Pi enthusiasts

On a damp and cold Saturday in early March the Cambridge University Computer Laboratory threw open its doors to the Raspberry Pi community. The previous Monday had been the fourth (or first, if you are a leap year pedant!) birthday of the little single-board computer, and last weekend saw its official birthday celebration.

The festivities took the form of an exhibition floor with both traders and community show-and-tell exhibits, plus a packed schedule of workshops and talks. With the Raspberry Pi 3 launch only a few days before there were no surprise announcements of exciting new hardware, but it did provide a good networking opportunity for the Pi community and a chance to test the state of the Raspberry Pi nation.

The most obvious first impression at the event was that it was one that catered for a diverse range of ages and ability groups. Side-by-side with parents and their children were educators, and the maker community. The range of exhibits was therefore slanted somewhat towards a younger age range with games and interactive exhibits, and there was more than a slight educational flavour to the event. This was entirely in keeping with the Foundation’s objectives, and since it is events like these that are inspiring the Hackaday readers of the next decade, a very welcome sight. Join us after the break for a look at all that was happening at the event.

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