CNC Clock Mills Itself, Displays The Time

May 28, 2016 by Elliot Williams 42 Comments

[Christian] wrote and sells some CAM/CNC controller software. We’re kinda sticklers for open source, and this software doesn’t seem to be, so “meh”. But what we do like is the Easter egg that comes included: the paths to mill out the base for a clock, and then the codes to move steel ball-bearings around to display the time.

Of course we’d like to see more info (more, MORE, MOAR!) but it looks easy enough to recreate. We could see redesigning this with marbles and a vacuum system, for instance. The seats for the ball bearings don’t even need to be milled out spheres. You could do this part with a drill press. Who’s going to rebuild this for their 3D printer? You just have to make sure that the machine is fast enough to move the balls around within one minute.

Continue reading “CNC Clock Mills Itself, Displays The Time” →

IPad Control For Guitar Pedals

May 28, 2016 by Elliot Williams 4 Comments

[gutbag] is a guitarist. And guitarists are notorious knob-twiddlers: they love their effects pedals. But when your music involves changing settings more than a few times in the middle of a song, it can get distracting. If only there were little robot hands that could turn the knobs (metaphorically, sorry) during the performance…

Tearing into his EHX Pitch Fork pedal, [gutbag] discovered that all of the external knob controls were being read by ADCs on the chip that did all of the processing. He replaced all of the controls with a DAC and some analog switches, coded up some MIDI logic in an ATmega328, and built himself a custom MIDI-controlled guitar pedal. Pretty slick, and he can now control it live with his iPad, or sequence the knobs with the rest of their MIDI system.

This wasn’t [gutbag]’s first foray into pedal automation, however. He’d previously automated a slew of his pedals that were already built to take control-voltage signals. What we like about this hack is the direct substitution of DAC for potentiometers. It’s just hackier. (Oh, and we’re envious of [gutbag]’s lab setup.)

This isn’t the first time we’ve covered [gutbag]’s band, Zaardvark, either. Way back in 2013, we featured an organ-pedal-to-MIDI hack of theirs. Keep on rockin’.

Continue reading “IPad Control For Guitar Pedals” →

Minimal MQTT: Control And Clients

May 27, 2016 by Elliot Williams 10 Comments

So you’ve built a central server and filled your house with WiFi-connected nodes all speaking to each other using the MQTT protocol. In short, you’ve got the machine-to-machine side of things entirely squared away. Now it’s time to bring the humans into the loop! We’re going to explore a couple graphical user interfaces.

You could build a physical knob and/or LED display for every little aspect of your entire system, but honestly, this is where GUIs really shine. In this installment of Minimal MQTT, we’re going to look at human-friendly ways of consuming and producing data to interact with your connected sensors, switches, and displays. There are a ton of frameworks out there that use MQTT to build something like this, but we’re going to cut out the middle-man and go straight for some GUI MQTT clients.

Continue reading “Minimal MQTT: Control And Clients” →

DTMF Robot Makes Rube Goldberg Proud

May 27, 2016 by Elliot Williams 11 Comments

Sometimes you start building, and the project evolves. Layers upon layers of functionality accrue, accrete, and otherwise just pile up. Or at least we’re guessing that’s what happened with [Varun Kumar]’s sweet “Surveillance Car Controlled by DTMF“.

In case you haven’t ever dug into not-so-ancient telephony, Dual-tone, multi-frequency signalling is what made old touch-tone phones work. DTMF, as you’d guess, encodes data in audio by playing two pitches at once. Eight tones are mapped to sixteen numbers by using a matrix that looks not coincidentally like the old phone keypad (but with an extra column). One pitch corresponds to a column, and one to a row. Figure out which tones are playing, and you’ve decoded the signal.

Anyway, you can get DTMF decoder chips for pennies on eBay, and they make a great remote-control interface for a simple robot, which is presumably how [Varun] got started. And then he decided that he needed a cell phone on the robot to send back video over WiFi, and realized that he could also use the phone as a remote controller. So he downloaded a DTMF-tone-generator app to the phone, which he then controls over VNC. Details on GitHub.

Continue reading “DTMF Robot Makes Rube Goldberg Proud” →

Fixing A Complicated Scrollwheel

May 26, 2016 by Elliot Williams 51 Comments

[Thomas] loves his Logitech MX Master mouse, which has a pretty elaborate scroll-wheel mechanism. Perhaps too elaborate; it broke on him after a week of use, just when he was getting used to the feature. So what did he do? Took it apart and fixed it, naturally. And as a bonus, we get a guided tour of the interesting mechanism. Check out his video below to watch it in action.

The weighted scroll wheel switches between two different modes, one with a detent like you’re probably used to, and one where the wheel is allowed to spin freely for long-distance travel. And to do this, it’s actually got a little motor inside that rotates a cam and throws a lever into the side of the scroll wheel for the detent mode, and pulls the lever out of the way for free spins. It must also have some logic inside that detects how quickly the scroller is spun because it re-engages as soon as the scroll wheel stops.

Continue reading “Fixing A Complicated Scrollwheel” →

Learn Functional Reactive Programming On Your Arduino

May 25, 2016 by Elliot Williams 49 Comments

Everyone loves learning a new programming language, right? Well, even if you don’t like it, you should do it anyway, because thinking about problems from different perspectives is great for the imagination.

Juniper is a functional reactive programming language for the Arduino platform. What that means is that you’ll be writing your code using anonymous functions, map/fold operations, recursion, and signals. It’s like taking the event-driven style that you should be programming in one step further; you write a=b+3 and when b changes, the compiler takes care of changing a automatically for you. (That’s the “reactive” part.)

If you’re used to the first-do-this-then-do-that style of Arduino (and most C/C++) programming, this is going to be mind expanding. But we do notice that a lot of microcontroller code looks for changes in the environment, and then acts (more or less asynchronously) on that data. At that level of abstraction, something like Juniper looks like a good fit.

Continue reading “Learn Functional Reactive Programming On Your Arduino” →

Black Line Follower: A Modern Bristlebot

May 25, 2016 by Elliot Williams 5 Comments

It’s been a while since we’ve seen much action on the bristlebot front, which is too bad. So we’re happy to see [Extreme Electronics]’s take on the classic introductory “robot”: the Black Line Follower. The beauty of these things is their simplicity, so we’ll just point you to his build instructions and leave the rest to you.

The original bristlebot is a fantastic introduction to electronics, because it’s simple enough that you can cobble one together in no time. A battery, a pager motor, and a toothbrush head are all you need. But it goes where it wants, rather than where you want it to go.

Adding steering is as simple as tying two bristlebots together and firing one motor at a time to execute a turn. The Black Line Follower is of this style.

Of course, any good idea can be taken to extremes, as in this giant weight-shifting bristlebot, or this super-tiny IR-controlled bristlebot.

But that was more than five years ago now. What happened to the mighty engines of bristlebot creativity? Has the b-bot seen its finest hour? Or are we just waiting for the next generation to wiggle up to the plate?

Continue reading “Black Line Follower: A Modern Bristlebot” →