I can't think of anything to add to the official description of the LittleWire. For me, it's a cool tool to build, and a cool tool to have on hand, mostly for programming AVR chips.

• usbtinyisp compatible AVR programmer.
• 4 channel GPIO.
• ADC with 10 bit resolution.
• 2 parallel hardware PWM outputs.
• SPI interface.
• I2C interface.
• 1-Wire interface
• WS2812 RGB LED interface.
• Multiple device support.

A while back, I used a round piece of perfboard to make a smd-like LittleWire… No schematics, it's directly inspired from the Schematic of the Little Wire. The only difference is: D+ and D- are swapped to make it easier to solder…

It's a little bit messy, but it worked, and still does its job !

I was a little bored and wanted to practice SMD soldering, just for fun. So I made an SMD version of the LittleWire.

• Small footprint
• MiniUSB connector
• Easy to use header ⇒ Can be plugged in a breadboard !
• Micronucleus bootloader

I still haven't made a schematic, so please, refer to the annotated PCB to assemble the board. Sorry, it's a little bit crowded, but everything should fit nicely… 600 DPI image, as usual around here…

Pin 1 of the Attiny is on the top right of the PCB, near D3

I received some micro USB connectors, and wanted to try out my new PCB exposure box, so I replace the MiniUSB connector to a MicroUSB one. It made the board 3mm shorter !

Here's the new PCB:

Required

• D1, D2: 3.6v Zener Diodes
• R1, R2: 39 Ohms
• R3: 1.5 kOhms
• C1: 1 µF
• Attiny85
• 6 Pins Header, straight
• MiniUSB connector

Optional

• C2: 68 nF
• D3: Blue LED
• R4: 1 kOhms

Pin 1 is the closest to the USB port. The pinout is then:

1. Vcc
2. Gnd
3. /Reset
4. SCLK
5. MISO
6. MOSI

Once you get used to this pinout, it's very handy to use ^^

I only re-host theses files in case the original goes missing. I haven't written those… Download: Micronucleus Bootloader (1.02) and LittleWire Firmware (1.3)

Flash an empty chip with: avrdude -c usbtiny -p t85 -U flash:w:micronucleus-1.02.hex -U lfuse:w:0xe1:m -U hfuse:w:0x5d:m -U efuse:w:0xfe:m And then use the Micronucleus software to flash the LittleWire firmware.