People often lament that leaving an entire Arduino inside a project is not very cost effective, nor space effective. While creating an entire custom circuit is an option, another is just to find a smaller and cheaper replacement. Adafruit has just announced their tiniest and cheapest Arduino-compatable development board for exactly this purpose.
The Trinket is tiny. Its dimensions are 31mm x 15.5mm. It could literally be hidden in a hem or cuff. You could mount this in a baseball cap and never notice the weight; too bad the same can't be said for batteries. The Trinket comes in two versions. The 3v model, which runs at 8Mhz and the 5V model that can run at either 8Mhz or 16Mhz. Both versions cost $7.95.
Here are the features from the Adafruit website:
ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM
Internal oscillator runs at 8MHz, but can be doubled in software for 16MHz
USB bootloader with a nice LED indicator looks just like a USBtinyISP so you can program it with AVRdude (with a simple config modification) and/or the Arduino IDE (with a few simple config modifications)
Mini-USB jack for power and/or USB uploading, you can put it in a box or tape it up and use any USB cable for when you want to reprogram.
We really worked hard on the bootloader process to make it rugged and foolproof, this board won't up and die on you in the middle of a project!
~5.25K bytes available for use (2.75K taken for the bootloader)
On-board 3.3V or 5.0V power regulator with 150mA output capability and ultra-low dropout. Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
Power with either USB or external output (such as a battery) -- it'll automatically switch over
On-board green power LED and red pin No. 1 LED
Reset button for entering the bootloader or restarting the program. No need to unplug/replug the board every time you want to reset or update
5 GPIO -- 2 shared with the USB interface. The 3 independent IO pins have 1 analog input and 2 PWM output as well. The 2 shared IO pins have 2 more analog inputs and one more PWM output.
Hardware I2C / SPI capability for breakout & sensor interfacing.
I got my hands on one when I ordered a bunch of LED toys and was able to get it up and running, powering a ring of LEDs in less than five minutes thanks to the Adafruit tutorial system. I did have to solder the header pins on, so maybe we'll say 10 minutes. Having it on my work bench, I couldn't help but get a picture to compare the size between this, the teensy 2.0, and the Raspberry Pi. These are not products you would usually compare, but they were available.
Also worth checking out the Digispark (http://digistump.com) - the first attiny85 dev board to do the USB+Bootloader thing with a whole ecosystem of shields, code, and users (first commercially produced, many projects did it first) - glad to have Adafruit join us with their awesome take on the concept!
I would tend to comment on the class of boards rather than this specific one. Something like this is not what you are going to put into a consumer device that has a production run of a million units, but it is a great building block for prototyping or low-rate manufacturing. I am very interested in this, given that I am more comfortable with a compiler than a soldering iron. I could use boards like this to drop into any number of projects.
This is a great board for Hobbyists, students and in general for MCU development Newbies.
For more experienced embedded developers this is not in my opinion ideal. Especially when you can buy STM32F0Discovery board with 64KFlash, 8K Ram, 48MHz 32-bit cortex-M0 STM32F0 core with tonnes of superior peripherals and a debugger for around $8-$10. A free IDE (Coocox.org) supports this chip.
Other boards that are similarly priced also include the TIVA C Launchpad board based on a 80MHz Cortex-M4F with 256K Flash and 32K ram. The board also includes a debugger and works with TI's CCS IDE. That board goes for about $12-$14.
Caleb, Max forced me to say that red is better... Please don't ask me why :) And re the board, I could say that small is beautiful but after this nail color story, let me just thank you for another blog with cool stuff.