Little Wire

Little Wire is multi-featured USB controlled open source hardware tool packed in a minimal form factor designed by ihsan Kehribar. Even though it has minimal form factor, and packed with full of features; there aren’t any SMT components involved, therefore it is very suitable for beginners to assemble.

This tool has to take instructions at run-time over USB. It can't work in a computer-less environment.

Note

V1.1 beta firmware released for the Little Wire. You can find the changelog and details from this link.

Features

• USB controlled multi-tool with:
  • 4-channel digital input / output
  • ADC (10 bit resolution)
  • 2 parallel hardware PWM outputs
  • SPI interface
  • I2C interface
• USBtiny compatible AVR programmer
• Printf style debugging over AVR-ISP pins
• USB to UART converter (alternative firmware -- CDC-232 port)
• Onboard serial bootloader for firmware upgrades
• Minimal form factor and all through-hole components
• Open Source Hardware design

Applications

• AVR programming /summon captainObvious
• LED dimming, color mixing
• General servo driving
• Pan and tilt servo control of a webcam for face tracking
• With additional motor driver IC, 2 wheel robot driving
• Analog voltage recording and plotting
• Controlling LED matrix displays by using SPI module to drive shift registers
• USB to SPI bridge
• USB to I2C bridge
• USB to UART bridge
• General purpose V-USB developement board

Packing list

• 1 x Little Wire PCB
• 1 x Pre-programmed Attiny85 chip.
• 1 x 8pin IC socket
• 1 x USB Male Type A connector
• 2 x 3.6v zener diode
• 2 x 100 nF capacitor
• 2 x 27 Ohm resistor
• 1 x 1.2 kOhm resistor
• 1 x 150 ohm resitor
• 1 x LED ( for power indication)
• 1 x 2pin male header
• 1 x 2pin jumper
• 1 x (2x3)pin male header

Pinout

Silkscreen	AVR-ISP	PWM/Servo	ADC	I2C	SPI	CDC-232	Bootloader
pin1	MISO	Channel_B	-	-	DO	TX	TX
pin2	SCK	-	Channel_1	SCL	SCK	RX
pin3	RESET	-	Channel_0*	-	CS	-
pin4	MOSI	Channel_A	-	SDA	DI	-	RX

Analog functionality on pin3 pin isn't stable but supported. Use it at your own risk.

Document Links

• Project homepage
• Github repository for firmware and libraries
• Dowload the entire repository
• Hardware files

What is included?

• Eagle schematic / layout files. Also in PDF format.
• Microcontroller firmware files and makefile
• Bootloader source files
• C function/header files for command line USB interface for Windows and Linux
• C++ class for Windows and Linux
• Processing library for Windows ( With reduced feature set ... )
• C# class for Windows USB interface ( in development ... )
• Example C projects for almost every feature of the board
• Example C++ projects for almost every feature of the board
• Example Processing projects
• Example C# project for analog voltage plotting based on zedGraph