The ultimate low-cost dev board

We see a lot of microcontroller dev boards here at Hackaday, so much that we’re jokingly considering changing our name to Board a Day. These devices – from Arduinos to Arduino-compatible boards, very, very small boards, to extremely powerful ARM devices – are a great way to learn about the wonders of controlling electricity with code. There’s a problem, though: if you’re teaching a class on programming microcontrollers, giving each student a $20 board is nearly out of the question.

This is where the shrimp comes in. It’s a very, very minimal Arduino-compatible circuit meant to control all the pins on an ATMega328. The components only cost about £1.40 ($2.25 USD) when bought in volume, making it perfect for teaching a class or workshop on the Arduino and giving each student a circuit to take home.

The basic circuit is just an ATMega328 – the same microcontroller used in the Arduino Uno – with a few caps, resistors, and a 16 MHz crystal. It’s a very bare-bones system, but once built and programmed provides all the functionality of a $25 Arduino.

Like all microcontroller platforms, there’s the chicken-and-egg problem of actually programming the device. The Shrimp team is using a CP2102 USB to UART bridge to program each shrimp. Not an inexpensive part, but it is of course possible to only have one serial bridge for each workshop.

OpenPLC, for industrial automation to Halloween displays

Stepping out onto just about any factory floor you’ll find complex automatons building anything and everything imaginable. These machines need to be controlled somehow and before the age of computers these manufacturing robots were controlled with relays wired together to produce a multitude of actions. Relays, no matter how reliable and bulletproof the are, can’t be programmed without rewiring the entire machine. Now, factories have programmable logic controllers to take care of their automation tasks.

[Thiago] built his own programmable logic controller and released it as open hardware.Included in the OpenPLC are four 24V inputs, four 24V outputs (two with PWM), 0-10V analog inputs, and USB, SPI, and I2C for programming and expansion.

If you’re building anything from an industrial machine in your garage, or simply want really awesome Halloween (or Christmas) decorations, the OpenPLC can take care of driving all the solenoids, motors, and actuators needed. With the extendable I2C and SPI busses, it’s possible to add a plethora of sensors to bring a project to life.

The OpenPLC is based on an ATMega328 and is compatible with Arduino code. There are a few extension boards for digital and analog IO, as well as Ethernet.

Emulating the DCPU on an AVR

[skywodd] just finished his own DCPU emulator (French, translation) based on [notch]’s upcoming game, 0x10c. The neat thing about [skywodd]’s build is his emulator uses the lowly ATMega328, the same microcontroller found in (some) Arduinos.

The DCPU specification goes over the operations required of any DCPU emulator. There’s a lot of crazy stuff here – a division instruction that takes only 3 clock cycles, using an overflow for carry conditions, and a complete lack of a JMP instruction – but [skywodd] was able to tease something apart from DCPU studio and a VGA interface

Everything in this emulator is built on a solderless breadboard, but the ROM and RAM isn’t complete yet. As of now, everything is handled by the ‘328, using 478 bytes of RAM on the microprocessor.

We promised we would be holding a contest for the best physical implementation of the DCPU when we caught wind of 0x10c, and [skywodd]’s build is starting to look like the beginnings of the winning entry. We honestly have no idea when we’ll be holding this contest, but it’ll probably be shortly after the first playable release. Go bug [notch] if you’d like to speed up the progress, because obviously Twitter abuse speeds up software development.

Defense Against the Dog Arts

It’s possible that it was [Matt Meerian]’s awesome pun that won us over, not his ultrasonic bicycle dog defense system, but that would be silly. [Matt] wanted an elegant solution to a common problem when riding a bicycle, dogs. While, obscenities, ammonia, water, pepper spray, and others were suggested, they all had cons that just didn’t appeal to [Matt]. He liked the idea of using C02 powered high pressure sound waves to chase the dogs away with, but decided to choose a more electronic approach.  He used a Atmel ATmega644 as the MCU, four 25kHz transmitters, and two 40kHz transmitters. When the rider sees a dog he simply flips a switch and it activates the transducers (along with, cleverly, a human audible horn so he doesn’t have to look down to know it’s working). So far [Matt] has not had a dog chase him in order to test it’s efficacy, but his cat clearly seems unaffected by the device as you can see after the break. Continue reading “Defense Against the Dog Arts”

Talking digital calipers make engineering more accessible


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!

Continue reading “Talking digital calipers make engineering more accessible”

Hacked parking disc can be controlled remotely


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.

Continue reading “Hacked parking disc can be controlled remotely”

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


[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.