Dots and Dashes… on a Roll!

morse code device

Morse code was once a staple of the communications industry, but with advancing technology it has become relegated almost exclusively to movies and a niche group of ham radio operators. [Jan] has created a device which might not put a stop to this trend, but will at least educate children on the basics of how Morse code works by visually displaying Morse code as it’s generated.

The setup is fairly simple. An old momentary switch (which could easily be used in an actual Morse code setup) activates two pieces of circuitry. The first is a 555 timer circuit that creates an audible tone when the switch is pressed so the user can hear exactly what an operator would hear when decoding a real Morse code message.

The second piece of circuitry is where the real genius lies: a continuously spinning roll of glow-in-the-dark tape is placed in front of a white LED. When the switch is pressed, the LED turns on, which produces dots and dashes on the roll of tape as it passes by. This eliminates the need for rolls of paper or a more complicated moving pen/pencil setup to draw on the paper which might also be less child-proof.

While [Jan] built this as a toy, the children who used it thoroughly enjoyed it! They even decoded some Morse code messages and used the device to practice on it. After a while they’ll easily be able to master the Morse code trainer!

Hackaday Links: January 19, 2014

hackaday-links-chain

[Nick] wrote in to tell us about his first blog post. He’s showing off a PWM LED driver he build around a 555 timer. This project uses a lot of basics; some 555 experience, PCB etching, and surface mount soldering. We’d like to know more about the blue substrate on his circuit board!

After seeing the BOM spreadsheet with KiCAD integration a couple of weeks back, [Vassilis] sent in a link to his own Excel-based Bill of Materials helper. We’re wondering if anyone has a similar tool that will work with Open Office?

While we’re on the topic of downloadable documents, here’s a reference PDF for all types of DC measurements. The collection is a free offering from Keithley. [Thanks Buddy]

Since you’re brushing up on your knowledge you may also be interested in a free online microcontroller course offered by UT Austin. They’re targeting the Tiva C Launchpad as the dev board for the class.

This website seems to be a little creepy, but the teardrop shaped 3D printed music box which is being shown off is actually rather neat.

Hackaday Alum [Phil Burgess] threw together a point and shoot camera for Adafruit. It’s a Raspberry Pi, camera board, touchscreen display, and USB battery all rubber banded together. The processing power of the RPi is used to add image processing effects which are shown off in the demo video.

We don’t own a DeLorean. If we did, we’d probably follow the lead of Queen’s University Belfast and turn it into and electric vehicle. [Thanks Jake]

The 3D photocopiers are coming. Here’s a hacked together proof-of-concept from [Marcelo Ruiz]. After laser scanning the part is milled from floral foam.

 

Completely analog electronic music box

For the Ottawa Mini-Maker Faire this year, [Steven Dufresne] created an electronic take on the classic mechanical music box.

A typical music box uses a sequence of bumps on a rotating drum to pluck the tuned teeth (called lamellae) of a metal comb. Steven ditched the drum and comb and replaced them with a strip of paper and a single 555 timer.  The timer is configured as an astable oscillator with a fixed capacitor and charging resistor.  The discharge resistor is selected via a series of 13 shaped wires that drag along the strip of paper.  When a wire drags over a hole, it is connected to a copper pad below that is soldered to a specific resistor.  This completes the circuit and generates a tone specific to the resistor selected.

While the electrical aspects of the project are fairly simple (not even requiring a circuit board), the mechanical parts are much more sophisticated.  Steven had problems getting the dragging wires to make good contact and keeping the paper roll pulled tight.  He outlines all of these challenges and how he solved them in his very thorough video summary (embedded after the break).  With all of his incremental improvements to the design, the finished music box stood up to a whole 14 hours of abuse at the Faire.

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A 555 player piano

555_timer_automatic_music_player

From simple buzzers to an Atari Punk Console, the simple 555 timer chip is the foundation of a whole lot of interesting lo-fi synth projects perfect for beginners. [Steven] put together a great tutorial for using the 555 timer in a rudimentary synth, and even went so far as to build a simple electronic player piano able to play a song from a sheet of paper with punched holes.

The basic 555 oscillator circuit is very simple – just a few caps and resistors and powered by a few batteries. [Steven] built the simplest 555 circuit, but used a line of graphite drawn on a piece of paper for the resistor controlling the frequency. It’s basically a drawdio built on a breadboard, and easy enough to build for even the most neophyte electronic tinkerer.

Going one step further, [Stephen] drew a long thick line of pencil graphite on a piece of paper and mounted eleven wire loops attached to the circuit over his improvised resistor. After cutting a few holes in a piece of paper, he was able to create a simple player piano with his 555 synth. It worked well enough to play Greensleeves, and is the perfect project for the budding electronics hacker.

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555-timer charges lead acid batteries

555-timer-charges-lead-acid-batteries

[Kenneth Finnegan] took the focus of a great design and redirected it to solve his own problem. What results is this lead acid battery charger based on the 555 timer. It’s not a top-of-the-line, all the bells and whistles type of charger. But it gets the job done with a readily available IC and no need to code for a microcontroller.

The original idea came from a solar battery charger entered in the 555 timer contest. The main difference in application between that and [Kenneth’s] application is the source. A solar array or wind turbine is limited on how much juice it can produce. But mains power can push a shocking (har-har) amount of current if you’re not paying attention. Herein lies the alterations to the circuit design. To control this he’s using a Laptop power supply as an intermediary and only implementing the constant current portion of the tradition 3-stage lead acid charging profile (those stages are explained in his write up).

He did a talk on the charger at his local radio club. You can see the 90-minute video after the break.

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monoPong: A CMOS 1-D Pong

We’ve seen a few 1-D pong games recently, and they’ve all be controlled using microcontrollers. Inspired by some of these hacks, [mischka] built the monoPong using a handful of logic chips.

The monoPong has four major components. A 555 timer in astable mode provides a clock source which is fed into a 4510 decade counter, which connects to a 4028 BCD to decimal decoder to drive the LEDs. Finally, a 4011 NAND gate IC is used to deal with the button presses. Two of the NAND gates form a RS flip-flop, and the other two NAND each player’s button with the last LED on the player’s side of the strip. If the player hits the button when their LED is on, the RS flip-flop toggles and changes the decade counter from count up to count down mode. This makes the ball bounce back.

[mischka] finished the project off by putting it in a wooden box and drilling holes for the LEDs, buttons, and a power switch. The final product looks pretty good, and is a great example of how you can use a couple logic chips instead of a microcontroller.

After the break, watch a quick game of monoPong.

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Blinky headgear

This hat has a chasing LED feature thanks to our old friend the 555 timer. [BananaSlug] even built in the option to change the speed at the push of a button.

His design starts out with a costume hat. Each of the 25 LEDs is soldered to a 2×4 hole chunk of protoboard. The LED package is pushed through a slit in the hat, but the protoboard remains on the inside where it can be sewn in place. From there [BananaSlug] soldered one negative bus around the circumference, and an individual positive lead from each module back to the control board. They’re addressed by a set of CD4017 decade counters which are clocked by the 555 timer circuit.

This is a great little analog/logic project and the style is perfect if you’ve got the coat to go along with it.