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programmable bike lamp

DigiSpark Arduino

The Arduino is essentially a programmable chip called a microcontroller with various inputs and outputs. The inputs can be used to read things like voltage or switches and the outputs can be used to drive external components such as LEDs or a speaker.

The chip itself is fully programmable which means you can write you own program (or "Sketch") to tell the chip what to do.

What is the ATTiny85 (aka Digispark)

The ATTiny85 chip is on a very small board. It still uses the same chip as many other Arduino projects. It does all the same thing as the other Arduino boards, it's just a lot smaller.

The chip at the heart of these boards is a "microcontroller" which is really just a very small computer. A microcontroller has a CPU, RAM, and flash storage all built into the tiny chip.

DigiSpark Arduino Microcontroller
MicrocontrollerATMEL - ATTiny85
Operating Voltage5 volts
Digital I/O Pins6
Analog Input Pins4
Max DC Current per I/O Pin20 mA
Flash Memory8 kB
CPU Speed16.5 MHz

What are all those pins for

The ATTiny85 provides a number of Digital and Analog pins.

Digital pins are either ON or OFF - nothing in between. ON=5V, OFF=0V. Likewise it can read a pin's connected input as either ON or OFF. P0, P1, P2 and P5 are connected to LEDs. (P3 and P4 are connected to the USB for programming and may not be used in this project.

Analog pins on the other hand can output a variable voltage value. Likewise, they can read any input voltage connected up to them. They aren't limited to just ON or OFF logic levels like the digital pins. The analog inputs on P2 through P5 are unused.

Generally if you want to turn something on or off, you use digital. If you want to do something more complicated like output or read a variable changing voltage you would use an analog pin.

What's the USB connector for

The USB port is used to upload Arduino programs (or "Sketches") to the chip. Once the Arduino software and drivers are installed on your computer you can connect the board via the USB port and upload programs to it from your computer using the freely downloadable Arduino software.

You must disconnect the 9V battery before connecting the USB port to your computer.

I Want to Hook It Up To My Computer

The Arduino community website has an excellent guide. There are guides for Windows, Apple, Linux, etc. Click here for a tutorial.

You will also need to add the Digispark board. See here for details.

Need More Help

Arduino has a massive community behind it on the internet. If you get stuck you won't be for long. You're sure to find an answer via a quick search on the internet.

The official Arduino community website can be found at www.arduino.cc.

This project conceived and designed by Malcolm Faed, the nitty gritty details are on his blog. Start at the original post and work forwards from there.