The team over at NerdKits recently put together a device aimed to help make the process of measuring things more accessible to those with disabilities. [Terry Garrett] is a Mechanical Engineering student, and as anyone who is in the field knows, it’s a discipline which requires taking tons of measurements. Since [Terry] cannot see he was often asking classmates to assist in measuring items during labs, but when he got a job at a nearby design studio, he knew he would have to find a way to take those measurements on his own.

Enter NerdKits.

[Humberto] wrote in to share how he and his team built a set of talking digital calipers to assist [Terry] in his daily tasks. They based the design off a previous project they worked on, getting digital readout data from a set of calipers. The DRO information is fed into an ATmega382p, which pieces together pre-recorded sound bites to announce the size of the object being measured.

As you can see in the video below, the system looks to work very well, and [Terry] is quite pleased with his new talking tool. We love seeing these sorts of hacks, because they truly make a difference in people’s lives – excellent job!

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If you have ever traveled around Europe, you are likely familiar with parking discs. Required in many countries that would rather not deal with parking meters, these devices are placed in the front of a car’s window, and indicate when the vehicle was parked. When parking enforcement officers come through the area, it makes quick work of identifying which cars need to be ticketed.

[Michael] received a fancy electronic parking disc as a gift, but the device was incredibly buggy, causing him all sorts of grief. After contacting the manufacturer and receiving no helpful response, he took it upon himself to get things working properly.

He dismantled the disc and found that like many products today, the microprocessors were locked down behind a layer of hard resin. Undeterred, he decided to rebuild it from the ground up using an ATmega microcontroller to provide basic parking disc functionality. He also armed his disc with a GSM modem and a GPS receiver – the former gives him the ability to communicate with the device, while the latter provides accurate time data while allowing him to keep tabs on the car’s location, should the need arise.

The hacked disc’s guts reside in his glove box, and can be controlled using his iPhone, making it easy to tweak his parking time at will.

Check out the video below to see his parking clock in action, and if you have questions on any part of the build, [Michael] says he’s more than happy to fill in any missing details.

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[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.

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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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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[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.

[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.

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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