BOO! Teach Arduino Basics With this Fun Ghost

Halloween is just around the corner, and the spooky themed tips are just starting to roll in. If you’re looking to one-up the basic store-bought decorations, and maybe teach your kid the basics of an Arduino while you’re at it — why not build a Peek-A-Boo Ghost!

Using an Arduino, two servo motors and an ultrasonic distance sensor it’s pretty easy to make this cute little ghost that covers its eyes when no one is around. They’re using cardboard for the ghost, but if you have access to a laser cutter at your hackerspace, you could make it a lot more robust using MDF or plywood.

When the ultrasonic distance sensor senses someone coming towards it, it’ll trigger the arms to move — though it’d be easy to add a small speaker element too and get some spooky music going as well!

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Controlling Guitar Amps With Servos

[fichl] plays electric guitar, and with that hobby comes an incredible amount of knob twisting and dial turning. This comes at a cost; he can’t change the settings on his small amp without taking his hands off the guitar. While larger, more expensive amps have multiple channels and footswitches, this tiny amp does not. Instead of upgrading, [fichl] came up with a device that turns his single channel amp into a completely programmable one, with just an Arduino and a handful of servos.

The amp in question – an Orange Dark Terror head – has just three knobs on the front of the chassis, volume, shape, and gain. [fichl] had the idea of controlling these knobs electronically, and the simplest solution he came up with is cheap hobby servos. These servos are mounted in an aluminum box, and mount to the knobs with a few shaft couplings.

The footswitch is the brains of the setup, with three buttons, four LEDs, and a DIN-5 output jack that delivers power, ground, and three PWM signals to the servo box. With the help of an Arduino Nano, [fichl] can change any of the knobs independently, or switch between twelve programmed settings. It’s an interesting setup, and something that could serve as a prototype for a much larger system on a much larger amp.

Camera Dolly uses Makeblock

We’d call it a robot, but [Eric Buijs] calls it a dolly. [Eric] bought a Makeblock starter robot kit last year, but never did anything with it. He recently wanted a camera dolly to help shoot project videos and the Makeblock hardware fit the bill.

[Eric] found that one of Makeblock’s example videos showed off a camera dolly but had no construction details. He cracked open the kit and got to work replicating what he had seen. Two 6V motors combined with a reduction gear, a belt, and some wheels, and the dolly now moves under computer control!

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Bootstrapping Motion Input with Cheap Components

Motion control is a Holy Grail of input technology. Who doesn’t want an interface that they can control with simple and natural movements? But making this feel intuitive to the user, and making it work robustly are huge hills to climb. Leap Motion has done an excellent job creating just such a sensor, but what about bootstrapping your own? It’s a fun hack, and it will give you much greater appreciation for the currently available hardware.

Let’s get one thing straight: This device isn’t going to perform like a Leap controller. Sure the idea is the same. Wave your hands and control your PC. However, the Leap is a pretty sophisticated device and we are going to use a SONAR (or is it really SODAR?) device that costs a couple of bucks. On the plus side, it is very customizable, requires absolutely no software on the computer side, and is a good example of using SONAR and sending keyboard commands from an Arduino Leonardo to a PC. Along the way, I had to deal with the low quality of the sensor data and figure out how to extend the Arduino to send keys it doesn’t know about by default.

The Plan

The plan is to take an inexpensive SONAR module (the HC-SR04) and an Arduino Leonardo and use it to perform some simple tasks by mimicking keyboard input from the user. The Leonardo is a key element because it is one of the Arduinos that can impersonate a USB keyboard (or mouse) easily. The Due, Zero, and Micro can also do the trick using the Arduino library.

I wanted to determine how many gestures I could really determine from the HC-SR04 and then do different things depending on the gesture. My first attempt was just to have the Arduino detect a few fingers or a hand over the sensor and adjust the volume based on moving your hand up or down. What I didn’t know is that the default Arduino library doesn’t send multimedia keys! More on that later.

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The Arduino Birthday Cake is No Lie

Making someone a birthday cake is very thoughtful, but not if they are watching their weight. [MrFox] found a way around that: an Arduino-powered birthday cake. Even if you don’t mind the calories, an Arduino cake is a novelty and sure to be a hit with a hacker who’s another year older.

The cake uses a UTFT LCD shield which eats up a lot of pins and memory, so the project uses an Arduino Mega. A speaker plays the happy birthday song (which may even be legal now) while a microphone detects the birthday boy or girl blowing out the virtual candles.

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Frozen Time Photography with a 100W LED

High speed photography is fun. Ultra high frame rate video, even more so. But since not many of us have access to $10,000 HFR cameras… we have to make do with long exposure shots a perfectly timed camera flash. You can design a system to trigger the flash at just the right millisecond — but they’re still pretty expensive typically.

[Electronupdate] has a 100W LED module and penchant for Arduino Nanos — so he wondered if he could make an affordable high speed camera rig — and he did.

It’s a pretty slick little setup. He has a limit switch mounted to a nail on a piece of wood — when the water balloon drops on it, it triggers the mechanical switch. The Arduino then triggers the LED flash, which is quite a large load and requires a High Side Switch to operate. A small LCD and series of buttons allow him to dial in the time offset just right in order to get some awesome photos of a water balloon exploding.

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Just Don’t Call it an Old Remote

[Hari Wiguna’s] father is ninety years young. He started having trouble pushing the buttons on his TV remote, so [Hari] decided to build a custom remote that just has the buttons his dad needs. Oh, and the buttons are big.

There are a few interesting things about this project. [Hari] wanted to maximize battery life, so he went through a good bit of effort to keep the processor asleep and minimize power consumption. The remote is programmable, but [Hari] didn’t have access to his dad’s remotes. His answer was elegant. He used his Android phone to mimic the required remotes and provided a way for the remote to learn from another remote (in this case, the phone).
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