Collection of reference, tutorial, cheatsheet, tips and tricks for Arduino and related shields / modules. You can also get code snippets and alternative library for programming Arduino, highly optimized for better performance and smaller code size. Also feature some schematic for your Arduino projects. You can also build your own Arduino DIY from scratch, or hacking / tweaking Arduino boards according to your needs.
You can shrinkify your simple Arduino project into ultra tiny ATtiny13A microcontroller as long as your project code size doesn't exceed 1 Kb limit of ATtiny13A, and it doesn't use RAM / EEPROM over 64 bytes . Why would you do that? Because two important reason: it's cheap (vcc2gnd.com sell this microcontroller for as low as $1.5 / Rp17.000,- for Indonesian customer, even tinier and cheaper for SOIC version), and it certainly has much smaller form than your ordinary Arduino, even compared with Arduino smallest form (Arduino Micro).
If you need more power (bigger program code space, bigger RAM), you should consider using bigger version of ATtiny such ATtiny2313, but that's another story. For now let's focus with ATtiny13A (note that "A" suffix means newer version of ATtiny13 series, older version has no such suffix). Also note that for serious design / commercial product, you really should consider using newer series such ATtiny45 or ATtiny85 (same form factor with bunch of new capabilities).
To program any AVR tiny microcontrollers you can use SPI-based programmer such usbASP, or use your existing SPI-enabled board such Arduino (using ArduinoISP sketch, see following picture to see how simple it is to connect ATtiny13A to your Arduino)...
Your Arduino Uno comes with 16 MHz crystal, thus it runs at nearly 16 MIPS (since most of instructions are executed in single cycle). As you might know, Arduino Uno utilize ATmega328 MCU from Atmel. One obvious fact that strangely most of ordinary Arduino users don't know is that the MCU's top speed is actually rated at 20 MHz, not 16 MHz! 16 MHz is official speed limit of MCU used in early version of Arduino, ATmega8 (up to Arduino NG and Severino). Carried on with this obsolete limit, Arduino Uno is still clocked with 16 MHz crystal.
To boost your Arduino Uno's performance up to 25% faster, all you have to do is replace the 16 MHz crystal with 20 MHz crystal, and update the bootloader with one that designed for this upgraded speed (see instruction below).
Please note that this is NOT overclocking, we'll just tuning it to maximum speed allowed by manufacturer as stated in ATmega328 datasheet. So it's 100% safe and guaranteed to run as reliable as before, it's just 25% faster :) up to nearly 20 MIPS!
Step 1: Add following content to your boards.txt (located in hardware/arduino sub-directory of the Arduino application directory, i.e. \Program Files (x86)\Arduino\hardware\arduino in default installation path on 64-bit Windows (or \Program Files\Arduino\hardware\arduino if you're still using the immortal WinXP ;)...
Step 3: desolder the old 16 Mhz crystal from Arduino Uno board. Please note that this action may void your warranty, please proceed on your own risk! If you're unsure with this, perhaps it's better to build a brand new Arduino compatible board by your own from scratch. For example, you can buy Playduino-One kit from Play-Zone — they ship worldwide — for Fr. 19.9 (about USD 21). If you live in Indonesia, you can also purchase Playduino-One Kit from azTech for only Rp150.000,- (less than USD 14).
Step 4: Install a 20 MHz crystal. Soldering should be easy since space on bottom surface is sparse.
Step 5: Burn the bootloader: open Arduino IDE, if you've done step #1 correctly then a new board should be appear under Tools > Board menu with name Arduino Uno++ 20MHz. Select the new board, attach USB cable to Arduino (or ISP programmer if you build Playduino One), and execute Tools > Burn Bootloader command. That's all, now you have a much faster Arduino!
To boost your Arduino Uno's performance up to 25% faster, all you have to do is replace the 16 MHz crystal with 20 MHz crystal, and update the bootloader with one that designed for this upgraded speed (see instruction below).