Blynk with Joy

Last time, I talked about how my storage situation and my cheap nature led me to build an RC joystick controller with a cell phone app and an ESP8266. The key to making this easy was to use the GUI builder called Blynk to make a user interface for an Android or Apple phone. Blynk can communicate with the ESP8266 and makes the project relatively simple.

ESP8266 and Arduino IDE

The ESP8266 Blynk code is straightforward. You do need to set up the Arduino IDE to build for the ESP8266. That can vary by board, but here’s the instructions for the board I was using (from Adafruit; see below).

adaesp

Depending on the type of ESP8266 device you are using, you may need a 3.3 V serial cable or some other means of getting the firmware into the device. For the Adafruit device I had, it has a 5 V-tolerant serial connection so a standard USB to serial dongle plugs right in. There’s also two switches on my device. To get into bootload mode, you have to push the one button down, hold it, and then press the reset button. Once you release the reset button you can release the other button. The red LED half-glows and the device is then waiting for a download.
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The Joy of the ESP8266 and Blynk

I’ll admit it. I can be a little cheap. I also find it hard to pass up a bargain. So when I saw a robot kit at the local store that had been originally $125 marked down to $20, I had to bite. There was only one problem. After I got the thing home, I found they expected you to supply your own radio control transmitter and receiver.

Normally, that wouldn’t be a problem but lately… let’s just say a lot of my stuff is in storage and I didn’t have anything handy. I certainly didn’t want to go buy something that would double the cost of this robot that I really didn’t need to begin with.

However, I did have a few ESP8266 modules handy. Good ones, too, from Adafruit with selected 5 V I/O compatibility and an onboard regulator. I started thinking about writing something for the ESP8266 to pick up data from, say, a UDP packet and converting it into RC servo commands.

joymainSeemed like a fair amount of work and then I remembered that I wanted to try Blynk. If you haven’t heard of Blynk, it is a user interface for Android and Apple phones that can send commands to an embedded system over the Internet. You usually think of using Blynk with an Arduino, but you can also program the embedded part directly on an ESP8266. I quickly threw together a little prototype joystick.
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Hackaday Links: November 27, 2016

[Prusa]’s business is doing great. This year, he released the Prusa i3 Mk. 2, a four color upgrade to the printer, and sales are through the roof. There’s just one problem: Paypal just locked his funds. Prusa is turning away from Paypal and given Paypal’s history, this will eventually be worked out. Be warned, though: don’t use Paypal for your hardware business. We’ve seen this same story played out too many times before.

Those millennials are always on their phones. How do you get rid of that distraction? Airplane mode? No, that’s stupid. Put those phones in a metal box. It’s the exact same thing as airplane mode – which is free – but this extra special metal box costs $45 and ships in March. Is this metal box different from any other metal box, like a cookie tin, perhaps? Probably not.

Nothing to see here, folks.

The holidays are here, and it’s time for Cards Against Humanity to do something stupid with other people’s money. This year, they’re throwing money into a hole. No, really. People are contributing money to dig a gigantic hole. There’s a livestream of the digging. Five dollars lets the dig continue for another few seconds. Join in on the holiday spirit: throw your money into a hole.

You don’t want to throw your money into a hole? Buy some stuff on Tindie! There’s robots, CNC controllers, servo drivers, MIDI arpeggiators, USB testers, power supplies, blinky glowy things, and retro gaming stuff. Go plug your Raspberry Pi into some of these gizmos.

The Mechaduino is a board that clips onto a ubiquitous NEMA stepper motor to turn it into a servo motor.  It won 5th place in the Hackaday Prize last month, and we can’t wait to see it integrated into a closed-loop 3D printer. [Chris] came up with an Ethernet-enabled servo-stepper conversion, and now it’s a project on Kickstarter. Of course, you can buy a Mechaduino right now, making the future of stepper motor-controlled desktop CNC very interesting.

Individually addressable RGB LEDs exist, and we’re waiting for Clark Griswold to electrify his house in red, green, and blue. Until then, [Michel built a holiday ornament loaded up with 16 WS2812b LEDs. The star features caps and diodes to make everything work as it should and requires only three wires per star.

A Dual-purpose Arduino Servo Tester

RC flying is one of those multi-disciplinary hobbies that really lets you expand your skill set. You don’t really need to know much to get started, but to get good you need to be part aeronautical engineer, part test pilot and part mechanic. But if you’re going to really go far you’ll also need to get good at electronics, which was part of the reason behind this Arduino servo tester.

[Peter Pokojny] decided to take the plunge into electronics to help him with the hobby, and he dove into the deep end. He built a servo tester and demonstrator based on an Arduino, and went the extra mile to give it a good UI and a bunch of functionality. The test program can cycle the servo under test through its full range of motion using any of a number of profiles — triangle, sine or square. The speed of the test cycle is selectable, and there’s even a mode to command the servo to a particular position manually. We’ll bet the build was quite a lesson for [Peter], and he ended up with a useful tool to boot.

Need to go even further back to basics than [Peter]? Then check out this primer on servos and this in-depth guide.

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A Trove Of Arcade Projects

[Ryan Bates] loves arcade games, any arcade games. Which is why you can find claw machines, coin pushers, video games, and more on his website.

We’ve covered his work before with his Venduino project. We also really enjoyed his 3D printed arcade joystick based off the design of a commercial variant. His coin pushing machine could help some us finally live our dream of getting a big win out of the most insidious gambling machine at arcades meant for children.

Speaking of frustrating gambling machines for children, he also built his own claw machine. Nothing like enabling test mode and winning a fluffy teddy bear or an Arduino!

It’s quite a large site and there’s good content hidden in nooks and crannys, so explore. He also sells kits, but it’s well balanced against a lot of open source files if you’d like to do it yourself. If you’re wondering how he gets it all done, his energy drink review might provide a clue.

Primer on Servos Hits All the Basics

Servos are pretty basic fare for the seasoned hacker. But everyone has to start somewhere, and there’s sure to be someone who’ll benefit from this primer on servo internals. Who knows – maybe even the old hands will pick up something from a fresh perspective.

[GreatScott!] has been building a comprehensive library of basic electronics videos over the last few years that covers everything from using a multimeter to programming an Arduino. The last two installments delve into the electromechanical realm with a treatment of stepper motors along with the servo video below. He covers the essentials of the modern RC-type servo in a clear and engaging style that makes it easy for the newbie to understand how a PWM signal can translate into positional changes over a 180° sweep. He shows how to control a servo directly with an Arduino, with bonus points for including a simple 555-based controller circuit too. A quick look at the mods needed to convert any servo to continuous rotation wraps up the video.

If [GreatScott!]’s video whets your appetite for more, be sure to check out [Richard Baguley]’s deeper dive into servos. And when you’re ready to put your new-found knowledge into practice, maybe a nice project would be to convert a hobby servo into a linear actuator.

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A Robot Arm From The Cupboard

Building a simple robot arm is a lot more straightforward than it used to be.  If you have a laser cutter, or a bit of cash and don’t mind waiting for postage, there are inexpensive kits like the MeArm. If you have a 3D printer, there are any number of 3D-printed designs for you to tackle. What if you need to satisfy your urge to build a robot arm really quickly, and you don’t have a laser cutter or 3D printer? You’ve got a pile of servos from that remote-control project, how can you make the rest?

If you are [roboteurs], you raid the stationery cupboard, and create an arm using rubber bands, paper clips, and binder clips. The binder clips grip the servo arms and hold the whole thing together, the rubber bands provide extra attachment , and the paper clips are bent to form the jaws. It’s not the prettiest or perhaps the most capable of arms, but it undeniably is an arm, and we’d doubt it could be done any more cheaply.

In this particular case, the arm serves as a demonstration piece for [roboteurs]’ Printabots Maker Kit for people without a 3D printer. It uses their controller board, but there is no reason why it could not be used with any other board capable of driving servos.

We’ve covered innumerable robot arms over the years, This one may be the cheapest, but another contender might be this cardboard arm. None of them, however, are as cool as this steam-powered Armatron toy.