Arduino Hacks

3038 Articles

Convert Any USB Keyboard To Bluetooth

September 4, 2016 by 40 Comments

[DastardlyLabs] saw a video about converting a PS/2 keyboard to Bluetooth and realized he didn’t have any PS/2 keyboards anymore. So he pulled the same trick with a USB keyboard. Along the way, he made three videos explaining how it all works.

The project uses a stock DuinoFun USB mini host shield with a modification to allow it to work on 5V. An Arduino mini pro provides the brains. A FT-232 USB to serial board is used to program the Arduino. A standard Bluetooth module has to have HID firmware installed. [Dastardly] makes a homemade daughterboard–er, shield–to connect it to the Arduino.

The result is a nice little sandwich with a USB plug, a Bluetooth antenna, and some pins for reprogramming if necessary. Resist the urge to solder the Bluetooth board in–since it talks on the same port as the Arduino uses for programming, you’ll have to remove it before uploading new code.

If you need help reprogramming the HC-05 Bluetooth module, we’ve covered that before. This project drew inspiration from [Evan’s] similar project for PS/2 keyboards.

Continue reading “Convert Any USB Keyboard To Bluetooth” →

Hackaday Prize Entry: Magic Bit-Of-Wire Motion Detector Library For Arduino

September 1, 2016 by 11 Comments

We’re still not sure exactly how [connornishijima]’s motion detector works, though many readers offered plausible explanations in the comments the last time we covered it. It works well enough, though, and he’s gone and doubled down on the Arduino way and bundled it up nicely into a library.

In the previous article we covered [connor] demonstrating the motion detector. Something about the way the ADC circuit for the Arduino is wired up makes it work. The least likely theory so far involves life force, or more specifically, the Force… from Star Wars. The most likely theories are arguing between capacitance and electrostatic charge.

Either way, it was reliable enough a phenomenon that he put the promised time in and wrote a library. There’s even documentation on the GitHub. To initialize the library simply tell it which analog pin is hooked up, what the local AC frequency is (so its noise can be filtered out), and a final value that tells the Arduino how long to average values before reporting an event.

It seems to work well and might be fun to play with or wow the younger hackers in your life with your wizarding magics.

The HackadayPrize2016 is Sponsored by:

Cat-Operated Cat Food Dispenser

September 1, 2016 by 56 Comments

Tired of being harassed by your cat? [MomWillBeProud] made a cheap, effective — and more importantly cat-operated — cat food dispenser.

The feeder is of an efficient construction — a double cat food dish, one container to store the electronics, and a Pringles can to act as the hopper. A simple servo rotates the hopper thirty degrees and back on each button press; using gravity to drop food through an opening that appears due to this motion. The button itself is an old IKEA timer and a piece of plastic large enough for a hungry cat to swat.

An Arduino controls the servo, and while [MomWillBeProud] skips over going into detail on his code, you can check it out here.

Continue reading “Cat-Operated Cat Food Dispenser” →

Antenna Rotation Arduino Style

August 31, 2016 by 12 Comments

Back in the days when you didn’t pay for your TV programming, it was common to have a yagi antenna on the roof. If you were lucky enough to have every TV station in the area in the same direction, you could just point the antenna and forget it. If you didn’t, you needed an antenna rotator. These days, rotators are more often found on communication antennas like ham radio beams. For terrestrial use, the antenna only needs to swing around and doesn’t need to change elevation. However, it does take a stout motor because wind loading can put a lot of force on the system.

[SP3TYF] has a HyGain AR-303 rotator and decided to build an Arduino-based controller for it. The finished product has an LCD and is able to drive a 24 V motor. You can control the azimuth of the antenna with a knob or via the computer.

Continue reading “Antenna Rotation Arduino Style” →

The Evolution Of A DIY Circuit Board Plotter

August 31, 2016 by 23 Comments

In this three part video series we watch [Dirk Herrendoerfer] go from scraps to a nice 3D printed assembly as he iterates through the design of a pen plotter for making circuit boards.

[dana] mentioned [Dirk]’s work in the comments of this post which describes a different process. Many permanent markers stick to copper well enough to last through the chemical etching process. While hand drawing definitely produces some cool, organic-looking boards, for sharp lines and SMDs it gets a bit harder; to the point where it becomes advisable to just let a robot do it.

Of course, [Dirk] was aware of this fact of life. He just didn’t have a robot on hand. He did have some electronic detritus, fishing line, an Arduino, scrap wood, brass tubes, and determination.  The first version‘s frame consisted of wooden blocks set on their ends with holes drilled to accept brass rods. The carriage was protoboard and hot glue. Slightly larger brass tubing served as bushings and guide. As primitive as it was the plotter performed admirably, albeit slowly.

The second version was a mechanical improvement over the first, but largely the same. The software got a nice improvement. It worked better and had some speed to it.

The latest version has some fancy software upgrades; such as acceleration. The frame has gone from random bits of shop trash to a nicely refined 3D printed assembly. Even the steppers have been changed to the popular 28BYJ-48 series. All the files, software and hardware, are available on GitHub. The three videos are viewable after the break. It’s a great example of what a good hacker can put together for practically no money.

Continue reading “The Evolution Of A DIY Circuit Board Plotter” →

Pan And Tilt With Dual Controllers

August 30, 2016 by 14 Comments

It wasn’t long ago that faced with a controller project, you might shop for something with just the right features and try to minimize the cost. These days, if you are just doing a one-off, it might be just as easy to throw commodity hardware at it. After all, a Raspberry Pi costs less than a nice meal and it is more powerful than a full PC would have been not long ago.

When [Joe Coburn] wanted to make a pan and tilt webcam he didn’t try to find a minimal configuration. He just threw a Raspberry Pi in for interfacing to the Internet and an Arduino in to control two RC servo motors. A zip tie holds the servos together and potentially the web cam, too.

You can see the result in the video below. It is a simple matter to set up the camera with the Pi, send some commands to the Arduino and hook up to the Internet.

Continue reading “Pan And Tilt With Dual Controllers” →

Arduino Versus Logic: The Coil Gun War Continues

August 25, 2016 by 23 Comments

Looks like another shot has been fired in the simmering Coil Gun Control War. This time, [Great Scott] is taken to the discrete woodshed with a simplified and improved control circuit using a single CMOS chip and a few transistors. Where will it end? Won’t somebody think of the children?

The latest salvo is in response to [GreatScott]’s attempt to control a DIY coil gun with discrete logic, which in turn was a response to comments that he took the easy way out and used an Arduino in the original build. [Great Scott]’s second build was intended to justify the original design choice, and seemed to do a good job of explaining how much easier and better the build was with a microcontroller. Case closed, right?

Nope. Embedded designer [fede.tft] wasn’t sure the design was even close to optimized, so he got to work — on his vacation, no less!’ He trimmed the component count down to a single CMOS chip (a quad Schmitt trigger NAND), a couple of switching transistors, the MOSFETs that drive the coils, and a few passives. The NANDs are set up as flip-flops that are triggered and reset by the projectile sensors, which are implemented as hardwired AND gates. The total component count is actually less than the support components on the original Arduino build, and [fede.tft] goes so far as to offer ideas for an alternative that does away with the switching transistors.

Even though [fede.tft] admits that [GreatScott] has him beat since he actually built both his circuits, hats off to him for showing us what can likely be accomplished with just a few components. We’d like to see someone implement this design, and see just how simple it can get.