Often the Morse Code centered projects that we feature are to help you practice transmitting messages. This one takes a tack and builds an automatic decoder. We think [Nicola Cimmino's] project is well worth featuring simply based on his explanation of the Digital Signal Processing used on the signal coming in from the microphone. Well done. But he’s really just getting warmed up.

What makes this really stand out is a brilliant algorithm that allows conversion from Morse to ASCII using a lookup table of only 64 bytes. This provides enough room for A-Z and 0-9 without chance of collision but could be expanded to allow for more characters. Below is a concise description of how the algorithm works but make sure you take the time to read [Nicola's] project description in its entirety.

The algorithm can be decribed as follows. Have an index inside the lookup string inizialied to zero. Have an initial dash jump size of 64. At every received element (dot or dash) halve the initial dash jump and then increase by 1 the index inside the lookup string if a dot was received and by dash jump size if a dash was received. Repeat until a letter separator is reached, at that point the index inside the lookup string will point to the ASCII corresponding to the decoded morse.

Have you heard of this technique before? If so, tell us about it in the comments below. Before you jump all over this one, realize that Magic Morse uses a different technique.

[Nairod785] wanted to build a lock box that would lock from the inside. He started with an inexpensive, plain wooden box. This kept the cost down but would also allow him to easily decorate the box later on using a wood burning tool.

To keep the box locked, he installed a simple latch on the inside. The latch is connected to a servo with string. When the servo rotates in one direction, it pulls the string and releases the latch. When the servo is rotated in the opposite direction, the latch closes and locks the box once again.

If you are going to have a locked box, then you are also going to need a key to open it. [Nairod785] used a ring with a built-in NFC tag, similar to the ring featured back in March. Inside of the box is a PN532 NFC module. The walls of the box were a little too thick for the reader to detect the ring, so [Nairod785] had to scratch the wall thickness down a bit. The NFC module is connected to an Arduino Nano. Communications are handled with I2C.

The NFC ring actually has two different NFC tags in it; one on each side. [Nairod785] had to program both of the tag ID’s into the Arduino to ensure that the ring would work no matter the orientation.

The system is powered by a small rechargeable 5V battery. [Nairod785] wired up a USB plug flush with the box wall so he can easily charge up the battery while the box is locked. It also allows him to reprogram the Arduino if he feels so inclined. There is also a power switch on the side to conserve energy.

With Independence Day just around the corner, American hackers are likely to find themselves blowing things up in the name of Independence. It’s all great fun but it can also be dangerous. The standard ignition method of “use a lighter and run away really fast” is not exactly safe. Instead of lighting your fireworks the old-fashioned way, why not follow [Facelesstech's] example and build your own infrared controlled remote igniter?

The first step was to decide how to actually ignite the firework fuse. [Facelesstech] had seen others use a car cigarette lighter for this purpose and he decided to follow in their footsteps. He started by removing the cigarette lighter from his own car and pulling it apart. Only one component was needed for this hack. The main heating element is a small disk with a “stem” on the end. If you apply 12V to the stem and attach the outer edge of the disk to ground, the igniter will quickly become hot.

[Facelesstech] originally thought he could just solder some wires to the device. However, the heating element gets so hot that the solder just melts every time it’s turned on. He then got creative and drilled a hole in a small block of wood that fits the heating element. The element is bolted into the wood and the bolt is used as a conductor for the electrical power.

The heating element is powered via a 12V relay. The relay is controlled by an Arduino Nano. The Nano allows two modes of operation. With the first mode, you simply press a button and the Nano will start a five second timer. The idea is to give you enough time to run to a safe distance before the firework is ignited. This isn’t much different from the old-fashioned method, but it does give you a slightly extended fuse. The second mode is where the project really shines. The Nano is also hooked up to an infrared receiver. This allows [Facelesstech] to press a button on an old television infrared remote control to active the igniter. This is a clever solution because it allows you to get to a safe distance without having to run a long wire. It’s also simple and inexpensive. Be sure to watch the video test of the system below.

[Thanks Dale]

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Here’s a weekend junk bin project if we’ve ever seen one. [Pat] used a quartet of computer fans to make his laser Spirograph. Deciding to try this simple build for yourself will run you through a lot of basics when it comes to interfacing hardware with a microcontroller. In this case it’s the Arduino Nano.

The Spirograph works by bouncing a laser off of mirrors which are attached to the PC fans. When the fans spin the slight alignment changes cause the laser dot to bob and weave in visually pleasing ways. You can catch twenty minutes of the light show in the clip after the break.

Three of the fans have mirrors attached, the housing of the fourth is used to host the laser diode and make assembly easier. A TC4469 motor driver is used to connect the fans to the Arduino. The light show can be manually controlled by turning the trio of potentiometers which are read using the Arduino’s ADC.

If you manage your way through this build perhaps you’ll move on to a setup that throws laser light all over the room.

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Drawing on the popularity of the Tiny Tank, I decided that some folks might want wheels instead. I give you, Little Wheels.

The Little Wheels Robot is a great little bot for beginners and experienced robot builders alike. Simple, well designed and cute as a button, it is just a gosh darn good little bot.

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