ATtiny85 micro Programmer

5pcs x Atmel ATtiny85 20PU + dip socket + sticker $9.90

 Because I plan to make a wearable project, I try the capabilities of ATtiny85, an arduino IDE compatible microcontroller with 4(5) digital I/O pins. 

 I decide to buy from EU seller because I want fast shipping. In the same e-store (attiny85.blogspot.com) there is also a "ATtinyShield" so I try to build my own similar shield for my UNO board. When use the UNO as ISP Programmer the sketch give some readings in order to check if all went well. I use 3mm leds for this purpose: 

• Yellow - UNO Pin D7 - Programming / communication with the microcontroller
• Red - UNO Pin D8 - Error / something goes wrong
• Green - UNO Pin D9 - Heartbeat / ISP programmer is running

I add also one green 5mm test led connected to D3 or D0 pin of ATtiny85 selectable thru switch. Beware that when programming  is better to leave D3 connected with test led. In order to quick check the microcontroller I have merge the well known "Blink" and "Fade" examples of Arduino IDE.

// Fade & Blink test of ATtiny85 and my programmer shield

// initial declarations
int ledb = 4;
int ledf = 0;           // the pin that the LED is attached to
int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by

void setup()  {
  // pins declarations
  pinMode(ledb, OUTPUT);
  pinMode(ledf, OUTPUT);
}

void loop()  {
  analogWrite(ledf, brightness);   
  analogWrite(ledb, brightness); // D4 isn't PWM pin so the fade effect became blink!
 
  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade:
  if (brightness == 0 || brightness == 255) {
    fadeAmount = -fadeAmount ;
  }    
  // wait for 30 milliseconds to see the dimming effect   
  delay(30);                           
}

 One think that you must remember is that the ATtiny85 microcontroller came with 1MHz clock speed setting by the factory (the Blink/Fade effect will be tooo slow). So you have choose as board the 8MHz version and burn bootloader before upload the sketch.