Arduino Hacks

3036 Articles

Helicopter Pendulum Is PID-licious

November 8, 2016 by 23 Comments

If you’ve ever tried to tune a PID system, you have probably encountered equal parts overwhelming math and black magic folk wisdom. Or maybe you just let the autotune take over. If you really want to get some good intuition for motion control algorithms, PID included, nothing beats a little hands-on experimentation.

To get you started, [Clovis] wrote in with his budget propeller-based PID demo platform (Portuguese, translated shockingly well here).

The basic setup is a potentiometer glued to a barbecue skewer with a mini-quadcopter motor and rotor on the end of it. A microcontroller reads the voltage and PWMs the propeller through a MOSFET. The goal is to have the pendulum hover stably in midair, controlled by whatever algorithms you can dream up on the controller. [Clovis]’ video demonstrates on-off and PID control of the fan. Adding a few more potentiometers (one for P, I, and D?) would make hands-on tweaking even more interactive.

In all, it’s a system that will only set you back a few bucks, but can teach you more than you’d learn in a month in college. Chances are good that you’re not going to have exactly the same brand of sardine can on hand that he did, but some improvisation is called for here.

If you don’t know why you’d like to master open-loop closed-loop control algorithms, here’s one of the best advertisements that we’ve seen in a long time. But you don’t have to start out with hand-wound hundred-dollar motors, or precisely machined bits. As [Clovis] demonstrates, you can make do with a busted quadcopter and whatever you find in your kitchen.

Continue reading “Helicopter Pendulum Is PID-licious” →

IoT Coop Door Cares For Chickens, Tests Home Automation

November 6, 2016 by 28 Comments

Most chickens are pretty good at putting themselves to bed when the sun sets, and [Eddy]’s chickens are no exception. But they’re not terribly thoughtful about closing up after themselves, so he set about on a long-term project to automate the door of their coop.

An open door overnight leaves chickens and their food vulnerable to predation. Rather than handle the chore manually and risk one forgetful moment that could wipe out his flock, [Eddy] used a servo to power the door and an Arduino to control it. To keep track of bedtime and wakeup, a Raspberry Pi looks up the local civil dawn and twilight times online and tells the Arduino when the moment is at hand. The Pi cleverly caches the times for use the next day in case the WiFi connection is down, and also provides a web interface to check on the door’s status and manually override the cycle. Result: safe, happy chickens.

If all this seems a bit much for a simple job, [Eddy] agrees. But he’s using this as a testbed to develop a home automation framework that can be retasked at will. Sounds like he’s on the right track to us, but for more IoT animal husbandry tips, he’ll want to check out this small farm automation effort.

Continue reading “IoT Coop Door Cares For Chickens, Tests Home Automation” →

Personal Compass Points To Your Spawn Point

November 5, 2016 by 22 Comments

A conventional compass points north (well, to magnetic north, anyway). [Videoschmideo]  wanted to make a compass that pointed somewhere specific. In particular, the compass — a wedding gift — was to point to a park where the newlywed couple got engaged. Like waking up in a fresh new Minecraft world, this is their spawn point and now they can always find their way back from the wilderness.

The device uses an Arduino, a GPS module, a compass, and a servo motor. Being a wedding gift, it also needs to meet certain aesthetic sensibilities. The device is in an attractive wooden box and uses stylish brass gears. The gears allow the servo motor to turn more than 360 degrees (and the software limits the rotation to 360 degrees). You can see a video of the device in operation, below.

Continue reading “Personal Compass Points To Your Spawn Point” →

Minimal Arduino Clock

November 2, 2016 by 19 Comments

Making a clock with a common microcontroller like an Arduino isn’t very difficult. However, if you’ve tried it, you probably discovered that keeping track of wall time is difficult without some external hardware. [Barzok] has a very minimal clock build. It takes a handful of LED arrays with an integrated driver, an Arduino Nano, a real-time clock module, and a voltage regulator.

Continue reading “Minimal Arduino Clock” →

Rotary Cell Phone: Blast From A Past That Never Was

November 2, 2016 by 32 Comments

The 1970s called and they want their rotary dial cell phone back.

Looking for all the world like something assembled from the Radio Shack parts department – remember when Radio Shack sold parts? – [Mr_Volt]’s build is a celebration of the look and feel of a hobbyist build from way back when. Looking a little like a homebrew DynaTAC 8000X, the brushed aluminum and 3D-printed ABS case sports an unusual front panel feature – a working rotary dial. Smaller than even the Trimline phone’s rotating finger stop dial and best operated with a stylus, the dial translates rotary action to DTMF tones for the Feather FONA board inside. Far from a one-trick pony, the phone sports memory dialing, SMS messaging, and even an FM receiver. But most impressive and mysterious is the dial mechanism, visible through a window in the wood-grain back. Did [Mr_Volt] fabricate those gears and the governor? We’d love to hear the backstory on that.

This isn’t the first rotary cell phone hybrid we’ve featured, of course. There was this GSM addition to an old rotary phone and this cell phone that lets you slam the receiver down. But for our money a rotary dial cell phone built from the ground up wins the retro cool prize of the bunch.

Continue reading “Rotary Cell Phone: Blast From A Past That Never Was” →

Handheld Sudoku (Assuming You Have Large Hands)

October 31, 2016 by 11 Comments

[Hari Waguna] wanted to build a computerized Sudoku game. Ordinarily, that wouldn’t be a big deal. You can buy one, of course, but what fun is that? There’s plenty of apps for phones, but again, not much of a challenge. If you want to preserve your hacker cred, you’d use a CPU board like an Arduino or a Raspberry Pi with an LCD screen, right? But if you want to grow your hacker cred, you’d follow [Hari’s] lead and use 81 seven-segment displays and a membrane keyboard.

Driving that many displays takes some doing (in this case shift registers). [Hari] uses some other tricks, like reading the keyboard using a single pin (and a resistor network). He’s made several videos about the project, including the one below.

Continue reading “Handheld Sudoku (Assuming You Have Large Hands)” →

What’s New, ESP-32? Testing The Arduino Library

October 31, 2016 by 30 Comments

In case you missed it, the big news is that a minimal Arduino core is up and working on the ESP32. There’s still lots left to do, but the core functionality — GPIO, UART, SPI, I2C, and WiFi — are all up and ready to be tested out. Installing the library is as easy as checking out the code from GitHub into your Arduino install, so that’s exactly what I did.

I then spent a couple days playing around with it. It’s a work in progress, but it’s getting to the point of being useful, and the codebase itself contains some hidden gems. Come on along and take a sneak peek.

Continue reading “What’s New, ESP-32? Testing The Arduino Library” →