Standard Arduino boards are simply big. They are universal and pretty versatile. But in some cases it’s size may be un-convenient. If you still need Arduino in small sized PCB – build one.

Jaanus has build really small arduino – tinyDuino which is only 7.4mmx7.4mm size. It is definitely double size PCB with ATmega88 on a center. Jaanus tried to use smallest size components he could solder manually. AVR is clocked at 8MHz speed and has all basic I/Os available including USART, SPI, 4 analog channels, 1 digial I/O one LED. It is featured with auto-reset due to board constraints.

If you need to monitor distant objects you probably would go with wireless transmission. This project simply demonstrates a standard setup of RF data transmission channel using cheap 433MHz or 315MHz modules. They are connected to PIC16F877 microcontroller using HT640 encoder on transmitter side and HT648 decoder on receiver side.

With encoder you don’t have to take care of formatting data packets. Decoder in its hand automatically encodes data from received packet. Microcontroller only has to read it and perform its own actions. In this particular example there are two sensor data transmitted – LM35 temperature and potentiometer value. Set up simply monitors continuously and updates parameter change.

Most modern fridges and refrigerators already have temperature indicators. But older ones don’t. This may be fixed like Victor did. He built pretty simple dual thermometer where one indicates fridge and another freezer temperatures.

For his project he has chosen a PIC16F886 microcontroller, couple 4 digit seven segment displays and two DS1820 1-wire temperature sensors. Nice project which may find more purposes than measuring fridge temperatures.

This may sound unreal but this works. Three component FM transmitter probably is the simplest transmitter in the world. Ant the count of components can be reduced to two. This is because there are one Attiny45 chip and couple coin batteries – total three. If using one battery this makes two component FM bug.

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So where is the magic in all of this? Sprite_tm likes to dig much deeper in to inner structure of AVR. It appears that Internal RC oscillator is using PLL which allows getting different clock speeds. RC oscillator works at 8MHz and in order to get 16MHz internal clock 8MHz is multiplied by eight and then divided by 4. By tweaking internal RC calibration register he managed to overclock chip to 24MHz. This means that PLL is running at 96MHz which is withing FM range. By playing with calibration register he was able to get FM modulation. Without any external antennas range is limited but this works. Hardly practical but fun to try.

Normally when programing microcontrollers you have do install compiler tools locally on your PC. What if all this could be shifted online. All you would need to do open browser type in address and start writing code. Inventor Town has been doing this with MSP430 microcontrollers. This is cloud based MSP430 C compiler with simple IDE. All you need is to log-in with Google id.

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They seem to support couple microcontrollers including MSP430x2231 and MSP430x2211. Also don’t expect too much from editor – it is very basic. Overall this is great idea especially if you are moving person and would like to have tools withing reach of your hand. Another benefit of using cloud based tools like this is that you don’t have to worry about software updates – all is done in one place without your intervention.

Shift registers are first cheep choice when you need to expand digital I/O pins say from one to eight. All you need is to clock serial data in in order to get all bits paralleled. Mika gives couple practical examples how this can be done using simple bit banging or SPI bus interface.

As microcontroller he have chosen Teensy board. As programming tool he selected Arduino IDE with Teensyduino add-on. In programming examples he used two types of shift registers – SN74HC595 and TPIC6B595. Second one is used in higher power applications. Both of them need three pins on input side: Data, Latch and Clock. As mentioned above it can be done using bit bang method where data mus be clocked in in program flow. So you need to write function that takes care of clock signal, latch and data output. This method is more obvious but occupies processor time. While using built in SPI you can set and forget. Data is shifted out automatically without using processor time.

You know that all apple gadgets have their price. And probably most of that price goes in to design not whats inside. If you don’t care of design then check out this Apple remote shield for Arduino. It can be assembled in no time.

All you need to do is to solder 5 push buttons and couple IR LEDs. And of course make it fir into Arduino board. After you flash the chip you’ll be able to send simple commands to your Mac, iPod and hopefully Apple TV.

When you feel that Atmega microcontroller runs out of juices and you don’t want to change to different type of microcontrollers like ARM then you can go with Xmega. Problem is that Xmega chip packages are less friendly for hobbyists but still usable. Having this in mind Brendan assembled Xmega breakout board which simply fits in to breadboard for fast prototyping.

The board includes ATXMega32a4u microcontroller alongwith power supply, USB port and I/Os aligned to fit nicely in to the breadboard. His intent is to make it more friendly for newbies by adding Arduino support for it. As a reference he’s using the XmegaDuino project. There is still lots of work to be done but you can start building one for yourself as you know it takes some time. [via dangerous prototypes]

Operating microcontrollers without interrupts is very inefficient. One of common used microcontrollers among hobbyists id AVR. Starters probably would go with Arduino board where AVR Atmega168/328 is used. It doesn’t matter weather you are programming in Arduino style or plain C it is advised to use interrupts. EngBlaze has written a tutorial on programming AVR timers using interrupts.

tutorial thoroughly goes through all information you may need including: what is timer, types of timers and finally running them in various modes. Once timers are set most of work is done in hardware with short interrupt routines where changes can be made. If you interested more about timers we have written couple tutorials on programming them using C.

A display with 16 digits can be used to display quite a lot information. One of these around the house could display some actual data like temperature, time, date or any type of messages. If you want one then take a look at this instructabe posted by Panici.

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He used already assembled 16 digit seven segment display from dealextreme. As a driver he has chosen an Attiny85 microcontroller that can also be programmed in Arduino manner by using an Attiny45-85 support package. Once you are in arduino here is a tm1640 library that allows start building what you need without digging too deep.

Greg designed a small sized 8×8 b-color LED matrix toy that allows doing fun stuff. Device PCB matches the size of LED display. It features MSP430G2201 microcontroller that ensures low power consumption because backpack is powered with CR2032 battery.

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Software is written in ASM language and compiled with open source naken430asm compiler. If you want to display some graphics, there is a perl script that allows converting PNG in to sprite image. Greg had fun building this toy so he has plans on doing a second version with some improvements he learned with first run.

Tobis had a great X1 espresso machine, but its electrical part wasn’t accurate enough with lack desired functionality. Without hesitation he decided to redo controller part by his own.

He grabbed Atmega16 and graphical OLED display that fit nicely instead original indicator. He measured temperature with thermocouple using MA6674 converter IC. Having graphical LCD here gave Tobis more ways to indicate whats going on inside machine. He added a graph trace of temperature, times and date display. Also microcontroller allows programming various espresso preparation timings and regimes. (translated)

Couple decades ago BASIC language was quite popular. If you feel sentimental about those old style BASIC interpreters then take a look at Geoff’s project so called Maximite. It is a PIC32MX based basic interpreter box that can be used to play with BASIC around. It has 128k of ram on PIC microcontroller, VGA output, PS/2 interface to connect keyboard. Also you can use USB and SD cards to store and load your programs.

Board also has 20 programmable I/O pins that makes it real fun to interact with external hardware. I/O pins can be used for digital and analog voltages. BASIC interpreter supports floating point arithmetic’s, string values with full file I/O. Interpreter can handle up to 40000 program lines per second. If new firmware is released – it can be upgraded easily with bootloader via USB interface.

Probably you’ve seen LilyPad – and arduino compatible dev board which is mainly used in fabric based electronics. Lots of people love adding electronics in to clothes. These can be anything from LED signs or more advanced projects. Adafruit announced a new open source platform Flora, which is gonna be a great competitor to LilyPad.

This is a new platform with new features some people may find interesting. First of all it is smaller size 1.75” diameter. It is based on Atmega32u4 what means that it have native USB support and obviously has HID functionality. You will be able to to program Flora to act like mouse, keyboard or MIDI device. Flora is module based system where with sewable conductive threads you can connect Bluetooth, GPS, accelerometers and many more sensors and devices. Limor Fried known as Ladyda have put lots of thought in it so it’s gonna be great refresher among wearable electronics hobbyists.

POV displays are fun and there are many ways of building them. Rucalgary decided to go with 64 RGB LED display in a tube. He assembled an aluminum frame where all electronics sits. POV display is controlled by Atmega1284p which have just enough SRAM for storing images.

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It is still initial version of software which shows demo image. He’s working on adding ZigBee (or Bluetooth) based image update. And yes, the vibration when spinning, but overall this looks great and with little balancing it is impressive piece of art.

Usually when you need live data update in webpage you usually use java script polling method. This is still argued but polling ads network throughput overhead and latency. Technology doesn’t stand in place and new standards enters the game. Along with HTML5 there came a web sockets that allow client-server live data exchange without latency and efficiently. Blaise Jarret being an expert on PIC microcontrollers decided to implement websockets based communications. As starting point he used mbed based project.

Embedded Websockets demonstration from Blaise Jarrett on Vimeo.

He set up a python based Autobahn server to talk to client script. Most modern browsers already support web-sockets. PIC microcontroller talks to server using a Wifly wireless module. Once device sends its message to server it instantly echoes back to web browsers. You can see a nice demonstration with potentiometer on a video. Dig that info and start your live sensor monitoring on webpage project.

Controlling microcontroller pins is a first task you usually do when learning. With AVR it is simple you grab some chip and write simple code in C language. In order to output a logic level to AVR pin you only need couple lines of code where you set up port direction register and port itself. Pete takes use through all of this with different approach.

Having in mind that C code may grow in to mess without proper coding discipline, he suggests to try programing in C++. In AVRStudio5 it is easy – you only need to select cpp file instead of C when creating source. Keep in mind that cpp tends to grow in to bigger program size and lower speed as well. But sometimes speed isn’t main criteria. C++ is object oriented programming language so you get lots of handy techniques to achieve results. Arduino is already based on C++ so that end user could easily use prepared libraries. They sacrifice speed and size for easier coding experience. Anyway its your choice – use plain C (especially on smaller MCUs) and have better performance, or give a try with C++ and find it more modular and fun.

Surrounding environment is full of data. It can be temperature, pressure, humidity, light intensity, sound level. LVL1 Luisvile Hackerspace have put a sensor array board to collect most of these data. It is based on Arduino compatible Atmega328 microcontroller.

Most sensors are well known and widely used among hobbyists. Temperature is measured using TMP102, humidity and temperature is also measured with DHT11. Another sensor BMP085 also incorporates temperature sensor along with pressure and altitude sensors. So here are totally three temperature sensors… There also are couple light sensors CDS and TSL230R that measures ambient light intensity. For proper data logging there are RTC chip that keeps counting date-time. Additionally there is a sound detector on board where you can get sound level at particular time or simply trigger actions with sound. Fun toy to play with…

Clap activated circuits has been for some time around. But most of them simply toggled the output. Pete have bought few cheap lamps and used them for his smart clapper project. He didn’t want to limit functionality with just turn on and off but added couple new interesting features.

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As normally it toggles the AC switch when there are two claps within one second. If three claps are hared within one second them PWM dimming starts until fourth clap is detected. Additionally there is another relay which may be activated with laser beam. Laser is detected with photo-transistor. Device is controller by Attiny2313microcontroller which activates two 12V halogen lamps through transistor keys, one device is controlled using relay. Microphone captures sound, then amplifies, filters it and then comparator gives a pulse that goes directly to microcontrollers external interrupt pin. Small and effective circuit that adds fun to your house.

If you know a bit about MIDI then you know that you can create music files out of notes. There are plenty of PC software that allows doing that. This Visual Music Composer tries to get rid of PC. Project is based on Altera DE2 FPGA board and this is where whole fun happens. Since there is no PC board has to take care of human input interface where PC keyboard is used. You can’t write notes if you don’t see them. So a another part is a VGA output – you can see what you’re doing on VGA screen.

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And of course there another hidden part – the brain “music reader and converter” which resides inside FPGA chip. Code reads whats been input by user and then converts music data in to audio signal. The interface is fairly simple. In VGA screen you can see a set of available notes and other music specific symbols and then you have music sheet where you can pick and place notes. It has lots of limitations. Seems it can’t play chords and there is no support for half tones. But its already fun to play.