Arduino Hacks

3040 Articles

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.

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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.

Rainy Day Fun By Calculating Pi

August 24, 2016 by 14 Comments

If you need a truly random event generator, just wait till your next rainstorm. Whether any given spot on the ground is hit by a drop at a particular time is anyone’s guess, and such randomness is key to this simple rig that estimates the value of pi using raindrop sensors.

You may recall [AlphaPhoenix]’s recent electroshock Settlers of Catan expeditor. The idea with this less shocking build is to estimate the value of pi using the ratio of the area of a square sensor to a circular one. Simple piezo transducers serve as impact sensors that feed an Arduino and count the relative number of raindrops hitting the sensors. In the first video below, we see that as more data accumulates, the Arduino’s estimate of pi eventually converges on the well-known 3.14159 value. The second video has details of the math behind the method, plus a discussion of the real-world problems that cropped up during testing — turns out that waterproofing and grounding were both key to noise-free data from the sensor pads.

In the end, [AlphaPhoenix] isn’t proving anything new, but we like the method here and can see applications for it. What about using such sensors to detect individual popcorn kernels popping to demonstrate the Gaussian distribution? We also can’t help but think of other ways to measure raindrops; how about strain gauges that weigh the rainwater as it accumulates differentially in square and circular containers? Share your ideas in the comments below.

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VFD Clock Only Speaks Romanian

August 24, 2016 by 9 Comments

There’s no shortage of clock projects, but [niq_ro] has his own take using a vacuum fluorescent display (VFD), and Arduino, and a pair of MAX6921 ICs. Those chips are made to drive a VFD, and the use of two of the ICs required a bit of work. The Arduino is not a great time keeper, so the clock also uses a DS3231 clock module and a humidity and temperature sensor.

The clock is in Romanian, although there are some options for different text. You can find the code on GitHub and can see the result in the video below.

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DIY Coil Gun Redux: Life Really Is Easier With Arduino

August 22, 2016 by 41 Comments

A common complaint in the comments of many a Hackaday project is: Why did they use a microcontroller? It’s easy to Monday morning quarterback someone else’s design, but it’s rare to see the OP come back and actually prove that a microcontroller was the best choice. So when [GreatScott] rebuilt his recent DIY coil gun with discrete logic, we just had to get the word out.

You’ll recall from the original build that [GreatScott] was not attempting to build a brick-wall blasting electromagnetic rifle. His build was more about exploring the concepts and working up a viable control mechanism for a small coil gun, and as such he chose an Arduino to rapidly prototype his control circuit. But when taken to task for that design choice, he rose to the challenge and designed a controller using discrete NAND and NOR gates, some RS latches, and a couple of comparators. The basic control circuit was simple, but too simple for safety — a projectile stuck in the barrel could leave a coil energized indefinitely, leading to damage. What took a line of code in the Arduino sketch to fix required an additional comparator stage and an RC network to build a timer to deenergize the coil automatically. In the end the breadboarded circuit did the job, but implementing it would have required twice the space of the Arduino while offering none of the flexibility.

Not every project deserves an Arduino, and sometimes it’s pretty clear the builder either took the easy way out or was using the only trick in his or her book. Hats off to [GreatScott] for not only having the guts to justify his design, but also proving that he has the discrete logic chops to pull it off.

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Hacked Furby Knows When You’re Near

August 21, 2016 by 7 Comments

One of the classics of circuit bending is to mess around with the clock chip that drives the CPU in simple noise-making toys. [Goran] took this a step further with his Furby hack. Skip down to the video embedded below if you just want to see the results.

After first experiments modifying the Furby’s clock with a string of resistors (YouTube), [Goran] decided to opt for more control, overriding the clock entirely with a square wave coming out of an Arduino. And then, the world became his oyster.

The Furby’s eyes were replaced with ultrasonic distance sensors, and what looks like a speaker was hot-glued into its mouth. Since this particular Furby only “talks” when you pull its tail, he naturally wired in tail-switch control to boot. As [Goran] suggests, a light show is the obvious next step.

If you haven’t pulled apart an electronic toy and played around with glitching it, you don’t know what you’re missing. We’ve got a classic intro to circuit bending, as well as projects that range from the simple to the ridiculously elaborate. It’s a fun introduction to electronics for the young ones as well. Grab a toy noisemaker and get hacking.

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Using Robotics To Film The Perfect Hamburger Shot

August 21, 2016 by 20 Comments

It’s no secret that a lot of time, money, and effort goes into photographing and filming all that delicious food you see in advertisements. Mashed potatoes in place of ice cream, carefully arranged ingredients on subs, and perfectly golden french fries are all things you’ve seen so often that they’re taken for granted. But, those are static shots – the food is almost always just sitting on a plate. At most, you might see a chef turning a steak or searing a fillet in a commercial for a restaurant. What takes real skill – both artistic and technical – is assembling a hamburger in mid-air and getting it all in stunning 4k video.

That’s what [Steve Giralt] set out to do, and to accomplish it he had to get creative. Each component of the hamburger was suspended by rubber bands, and an Arduino timed and controlled servo system cut each rubber band just before that ingredient entered the frame. There’s even a 3D printed dual-catapult system to fling the condiments, causing them to collide in the perfect place to land in place on the burger.

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