This excellent content from the Hackaday writing crew highlights recurring topics and popular series like Linux-Fu, 3D-Printering, Hackaday Links, This Week in Security, Inputs of Interest, Profiles in Science, Retrotechtacular, Ask Hackaday, Teardowns, Reviews, and many more.
Some things just go hand in hand. Hacking and guitars are one perfect example. A huge number of hackers, makers, and engineers have at least dabbled in playing the guitar. Even those who don’t play have heard the swan song of the wayward guitarist “Bro, you fix amps?”. Seriously, once your guitar toting friends find out you tinker in electronics, you’ll never be left wanting for pizza or beer. This week’s Hacklet is about some of the best guitar projects on Hackaday.io!
What’s the biggest difference between writing code for your big computer and a microcontroller? OK, the memory and limited resources, sure. But we were thinking more about the need to directly interface with hardware. And for that purpose, one of the most useful, and naturally also dangerous, tools in your embedded toolchest is the interrupt.
Interrupts do exactly what it sounds like they do — they interrupt the normal flow of your program’s operation when something happens — and run another chunk of code (an interrupt service routine, or ISR) instead. When the ISR is done, the microcontroller picks up exactly where it left off in your main flow.
Say you’ve tied your microcontroller to an accelerometer, and that accelerometer has a “data ready” pin that is set high when it has a new sample ready to read. You can wire that pin to an input on the microcontroller that’s interrupt-capable, write an ISR to handle the accelerometer data, and configure the microcontroller’s interrupt system to run that code when the accelerometer has new data ready. And from then on everything accelerometer-related happens automagically! (In theory.)
This is the first part of a three-part series: Interrupts, the Good, the Bad, and the Ugly. In this column, we’ll focus on how interrupts work and how to get the most out of them: The Good. The second column will deal with the hazards of heavyweight interrupt routines, priority mismatches, and main loop starvation: the Bad side of interrupts. Finally, we’ll cover some of the downright tricky bugs that can crop up when using interrupts, mainly due to a failure of atomicity, that can result in logical failures and corrupted data; that’s certainly Ugly.
We’ve seen a wide range of emotional responses regarding [Ahmed Mohamed]’s arrest this week for bringing a clock he built to school. No matter where you fall on the political scale, we can all agree that mistaking a hobby engineering project for a bomb is a problem for education. People just don’t understand that mere mortals can, and do, build electronics. We can change that, but we need your help.
Our friends at NYC Resistor came up with a great idea. Why don’t we all build a clock? I want you to take it one step further: find a non-hacker to partner with on the project. Grab a friend, relative, or acquaintance and ask them to join you in building a clock from stuff you have on hand in order to promote STEM education.
Clocks have long been one of my favorite projects, and like the one shown above, most of my builds didn’t look anything like traditional clocks. Once you start getting into how clocks are built, you’ll be amazed at how accurate dirt-cheap clocks are and how difficult it can be to replicate that accuracy. Pass this knowledge on to your teammates. Teach them how to solder, or how to draw a schematic, or just how to open the case on some electronics without fear.
Post your project on hackaday.io and we’ll add it to the Clocks for Social Good list (message me with the link). If you decide to document it elsewhere just leave a link in the comments below. We’ll post a roundup of all these builds next week. I plan to repurpose the soldering workshop board I populated last week as the display for my clock. I’ll be helping a friend of mine learn to solder as part of the build!
Happy hacking, and thanks for helping to dispel fear and teach others about awesome engineering.
Need some inspiration to get going? You can always chat with others about it in the Hacker Channel. If you have an Arduino and some LED strips you can do something like this. Here’s a binary clock built with just a few LEDs. Or if you have a laser cutter at your disposal you can make a unique display with just a pair of motors.
In the wee hours of the late 17th century, Isaac Newton could be found locked up in his laboratory prodding the secrets of nature. Giant plumes of green smoke poured from cauldrons of all shapes and sizes, while others hissed and spat new and mysterious chemical concoctions, like miniature volcanoes erupting with knowledge from the unknown. Under the eerie glow of twinkling candle light, Newton would go on to write over a million words on the subject of alchemy. He had to do so in secret because the practice was frowned upon at that time. In fact, it is now known that alchemy was the ‘science’ in which he was chiefly interested in. His fascination with turning lead into gold via the elusive philosopher’s stone is now evident. He had even turned down a professorship at Cambridge and instead opted for England’s Director of Mint, where he oversaw his nation’s gold repository.
Not much was known about the fundamental structure of matter in Newton’s time. The first version of the periodic table would not come along for more than a hundred and forty years after his death. With the modern atomic structure not surfacing for another 30 years after that. Today, we know that we can’t turn lead into gold without setting the world on fire. Alchemy is recognized as a pseudoscience, and we opt for modern chemistry to describe the interactions between the elements. Everyone walking out of high school knows what atoms and the periodic table are. They know what the sub-atomic particles and their associated electric charges are. In this article, we’re going to push beyond the basics. We’re going to look at atomic structure from a quantum mechanical view, which will give you a new understanding of why the periodic table looks the way it does. In fact, you can construct the entire periodic table using nothing but the quantum numbers.
Continue reading “Don’t Understand The Periodic Table? It’s Just A Quantum Truth Table”
Washington DC has a vibrant hardware hacking community and it was out in force on Saturday night. We had over one hundred people through the door at Nova Labs in Reston, Virginia (DC metro area). This sleek and spacious hackerspace opened their doors for a Hackaday Meetup as part of a weekend packed full of activities.
The building that Nova Labs moved into not too long ago is a really well-suited area for a Hackerspace. The front half of the building includes a huge open space which has plenty of room for people to set up the hardware they wanted to show off. The back has a full woodshop, machine shop, and more, with classrooms and conference rooms in between.
Above are a set of hats with addressible LED strings wrapped around them which [ArsenioDev] brought along with him. Several members of the Wyolum team are involved with Nova Labs and they were showing off some LED matrix-based projects like the marquee cube and a 3-player reaction time game. And clacking away all night long is a vintage teletype machine that [Bob Coggeshall] fixed and connected to a Raspberry Pi.
One more go at new enclosures for the Amiga 1200. Yes, it’s a Kickstarter campaign, and we mentioned a similar the same campaign last month. The previous campaign received a little more than half of the desired funding in a 30-day campaign. The new campaign received half its funding in a week. The only difference? Now you can put a Raspberry Pi in a newly manufactured A1200 case. And they say Raspberry Pi consumerism isn’t a thing…
Cheap SLA printing service. [Ian] and Dangerous Prototypes have made a name for themselves with dirt cheap, acceptable quality PCBs. Now they’re going for custom prints on a resin machine. It’s $0.95 per gram (density is 1.3g/cc). That’s cheap.
[James Willis] built a floppy drive orchestra. There are 16 drives in this orchestra, all controlled by an FPGA. Here’s the writeup.
Here’s a video overview of a real, huge, rideable hexapod robot. ‘Wow’ is just about the only thing we got for this.
Western Digital introduced a hard drive made specifically for the Raspberry Pi. It’s a hard drive with a USB interface, and a USB cable that connects to the Pi, the drive, and a power adapter. In other news, externally powered USB hard drives exist. You can buy a 2TB drive for the price of the 1TB PiDrive. What was that thing about Raspi consumerism?
Next week is the Open Hardware Summit in Philadelphia. We’ll be there (or rather, I will). We’ll have a post on the OHS badge up on Monday. Would anyone like to go see the lady made out of soap? It’s right around the corner from the venue.
Balance: we humans take it for granted. Without the sense of balance provided by our inner ears, we would have a hard time standing or walking around. What’s easy for us can be very hard for machines though. Projects that balance things have long been a challenge for engineers, makers and hackers. And rightly so, as building a machine to keep an object in balance often requires some novel electronic and mechanical solutions. This week’s Hacklet is all about projects that keep an object – or themselves – in balance.
We start with [Manuel Kasten] and Balance Wheel. Inspired by a project at Chaos Communication Congress, [Manuel] created a hack that looks timeless. A stainless steel ball is balanced on top of a wooden wheel. The system detects the ball’s position using a solar cell. More light on the cell means the ball is slipping off the wheel. The system counteracts this by spinning the wheel to oppose the falling ball. In the old days this would have been an analog system. [Manuel] made things a bit more modern by using an ATmega644p processor. The video shows the wheel spinning a bit fast, as the system was tuned for a ping pong ball rather than a heavy steel roller.
Next up is [Jason Dorie] with Sideway. Sideway is a two-wheeled skateboard that self-balances. One of the best parts of this project is that most of the mechanical components are from electric scooters, which means they are easy to source. The frame is even easier: A solid piece of plywood supports the rider and all the electronics. Two scooter motors are driven by a Sabertooth 2x32A motor controller. A Parallax Propeller performs the balancing act, obtaining IMU data from an ITG3200 digital gyro and an ADXL345 accelerometer. Speed is controlled by leaning forward and back, like a Segway. Steering is controlled by a Wiimote nunchuck. Sideway is powered by 3 cell LiPo batteries. [Jason] says this ride gets a lot of attention every time he takes it out.
[Dominic Robillard] developed his Stair-climbing self-balancing robot as part of his masters degree at the University of Ottawa. We don’t know what grade his advisors gave him, but we give this project an A+. The robot is a 4WD off-road monster. Two heavy-duty drive motors give it tank style steering. The most impressive part of the robot are the two arms which allow it to roll its entire chassis up and over obstacles which would stop much larger robots. [Dominic’s] robot isn’t just statically balanced though – it can rear up and ride on two wheels Segway style. If it does tip over, the arms will lift it right back up!
Finally, we have [Paul Bristow] with Terabalance. [Paul] got his hands on an early copy of the TeraRanger One, a Time of Flight (ToF) sensor developed at CERN. He decided to test it out by using it to balance a ping pong ball on a wooden bar. The sensor had to be slowed down quite a bit in this application, data is only read about 1000 times a second and averaged. An Arduino reads the distance data from the sensor and uses that data to drive a hobby servo. No PID loops here, in fact, Terabalance is a great example of how a proportional only system will hunt forever. That said, it is good enough to keep the ball on the balance bar.
There are a plenty of balancing projects on Hackaday.io. If you want to see more, check out the new well balanced project list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. 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 Hackaday.io!
