Rear window LED display gives other drivers a piece of your mind

rear_window_led_matrix

[Gagandeep] was sick and tired of discourteous drivers on the highway, so he decided that he would put together a display to let them know what he thought of their poor driving skills. He planned on putting the display up in the rear window of his car, so he had to ensure that it did not obstruct his view while driving.

He decided that an LED matrix would be the best way for displaying images and text while on the go, so he got busy constructing a 40×16 mesh grid for his rear window. Using a wooden template to get the spacing and positioning just right, he spent several days soldering the 600+ LEDs to one another. He used 74HC595 shift registers to manage the LEDs in groups of 5 columns, while an ATmega AT89C51 was tasked with generating the text and images to be displayed. All of the ICs were deadbugged in place, helping achieve [Gagandeep’s] desire of keeping his view unobstructed.

While we’re not well-versed on the legality of such a display, it looks great when animated. There are plenty of pictures of the grid in various stages of construction as well as videos of it in action in his Picasa album, so be sure to check them out. If you are looking for code or Eagle files, you can find those here.

Video: Learning to program for the ATmega328p Part I

Many of you are familiar with the Arduino. Many of you hate it…* This post isn’t about the Arduino. It is about the processor that is at the heart of many Arduino boards. If you are in the camp of people who can’t understand why others dislike the Arduino so much, this series is for you. In this series of videos, [Jack] will explore how to program for the ATmega328p processor using C. If you have been programming for the Arduino, you may have had some issues with the speed of your code at points. Programming in C will allow you to wring out nearly the last ounce of processing power that the ATmega processors can provide. It will also let you access the peripherals on the processor directly and to switch between different processors when you need more (or less) capabilities.

In this first video, [Jack] shows you all of the features of the 3pi robot, which he will be using as a fancy development board for the ATmega328p. He then shows you how to get your development environment set up and then walks you through one of the sample programs provided for the 3pi robot.

*Here at Hackaday, we are officially neutral in the ongoing Arduino love/hate war. We don’t care what microcontroller is used in the hacks that we show, only that they are cool.

Video is after the break!
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Matchbox-sized line following robot

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While they are not nearly as complex as their self-navigating brethren, building line following robots is no simple task, especially when they are this small. The creation of [Ondřej Staněk], this matchbox-sized line following robot is quite impressive.

PocketBot’s 48mm x 32mm circuit board also acts as its frame, supporting the wheels, motors, microcontroller and more. The brains of the operation is an ATmega8 microcontroller mounted on the bottom of the bot. A pair of wheels are driven independently using a set of mobile phone vibration motors that power the bot at speeds of up to 0.35 meters per second. Line detection is achieved by using three different IR sensors paired with four IR emitters located at the front end of the bot.

PocketBot also has an IR receiver on its top side, which allows [Ondřej] to control the robot, tweak its parameters, or calibrate its sensors on the fly using an IR remote or his computer.

The PocketBot might not be the absolute smallest line following bot we’ve seen, but it’s pretty darn close!

Continue reading to see PocketBot in action.

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“Counting box” also saves calculators from small children

[Nathan]’s son really loves numbers and counting, and one of his favorite things to do is add 1 to a calculator over and over again. Being the awesome dad that he is, [Nathan] built his son a counting box that has a 10-digit rotary switch and two arcade buttons to add and subtract.

One goal of the project was to have the counting box retain memory of the display while being powered off. The easiest way to do this is to write the display data to the ATmega’s EEPROM. This EEPROM is only rated for 100,000 write cycles (although in practice it’s much higher), so [Nathan] included a 24LC256 in a little spasm of over-engineering. All the electronics are laid out on perf board, and the case is constructed from bamboo that was laser cut by Ponoko. The quality of the case itself is fairly remarkable – we’re really impressed with the finish and the magnetic battery access door.

From experience, we know that playing with an HP-15C eventually leads to a broken calculator and having our Nintendo taken away. We’re really happy for [Nathan]’s son, and wish we had our own counting box at his age.

Keeping tabs on your tabby with a camera and GPS

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[Janis] has an outdoor cat that likes to roam all over the neighborhood. He was curious to see what he was up to all day, so he decided to build a small cat cam to document the feline’s comings and goings. After the cat returned one evening with a snail riding along on his back, [Janis] thought it would be pretty interesting to see where the cat was going as well.

He calls his creation “CatEye”, and it consists of a small JPEG color camera and GPS sensor, both of which are managed by what looks to be an ATMega328. The camera snaps pictures as the cat roams around, while the GPS sensor records its location throughout its travels. All of the data is stored on an SD card, making it easy to transfer the pics and .KML files back to his computer. A few clicks later, he can see everywhere his cat has been, using Google Earth.

It seems like a pretty interesting project, and we would love to see some schematics and code so that we can strap one of these on [Caleb] our cat to see where he’s been all day.

Workshop lights so bright, they will give you sunburn

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There are few things more frustrating than trying to tinker at your workbench with suboptimal lighting. [Jeremy] was toiling away in his workshop one afternoon when he decided that he finally had enough, and set out to overhaul his lighting setup.

His workshop is incredibly bright now, sporting a handful of under the shelf CCFL tubes to complement the mixture of cool and warm LEDs that are mounted on the ceiling. One thing we really liked about his setup is that he added a handful of LEDs to the bottom of his workbench, aimed at the floor – perfect for those times when a tiny screw or SMD component goes missing.

Everything is controlled by an ATMega 328 that he shoved into a project box, allowing him to tweak the lighting to suit his needs using a few simple buttons and a small LCD panel.

[Jeremy] says that the entire thing is “overkill” and that it is decidedly the messiest wiring job he has ever done. For something that was put together hastily in an afternoon, we think it’s just fine. The only thing we’re left wanting is some schematics and source code.

As far as the overkill comment goes, say it with me: There. Can. Never. Be. Too. Many. LEDs!

Stick around to watch [Jeremy] give a demonstration of how the system operates.

[via Adafruit blog]

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Clocks built from old aircraft surplus parts

aircraft_indicator_clocks

A few years ago, Tube Clock forum member[Sine1040] bought a set of four brand new aircraft indicator units that were built some time in the early 70’s. He had no idea what the units were actually used for, but he did know that he could repurpose them into some pretty slick looking clocks.

He disassembled all four boxes and between them, scrounged enough parts to build three clocks. After gutting the clocks and rearranging the digits, he built a timekeeping circuit using an ATMega8 which is clocked by a DS32 oscillator.

While the time is displayed using the large projection-style digit displays, the seconds are ticked off in the left-most analog meter. Minutes are also represented in the clock’s right-most analog window, swinging the needle from top to bottom as each one passes.

[Sine1040] paid special attention to keeping the boxes looking as stock as possible, with the only external modification being a power plug installed in place of an old grounding screw. The clock is definitely a different take on keeping time, and we think it looks great.

Continue reading to see a quick demo video of the clock in action.

[Thanks Brian]

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