====== Used hardware devices ======
  * Raspberry Pi 2 Model B 1GB & 8GB NOOBS Edition [[https://www.element14.com/community/docs/DOC-73827/l/the-new-raspberry-pi-2-model-b-1gb-technical-specifications?ICID=rpi2-topban-links]]
  * SpeedLink CAPO Desk & Hand Microphone, black [[http://www.speedlink.com/?p=2&cat=384&pid=29950&paus=1]]
  * Incutex mini speakers [[http://www.amazon.de/dp/B00PW6EZQ2/]]
  * RAVPower 10400mAh Portable Power Bank with iSmart (3.5A Output, Dual USB)-Black [[http://www.ravpower.com/10400mah-portable-charger-power-bank-black-new.html]]
  * SparkFun RFID Starter Kit [[https://www.sparkfun.com/products/13198]]
  * Sunfounder AD/DA Converter PCF8591 Module [[http://www.sunfounder.com/index.php?c=show&id=145&model=AD/DA%20Converter%20PCF8591%20Module]]
  * Buttons (2 x momentary, 3 x toggle)
  * Phidget 1112_1 - Slider 60 [[http://www.phidgets.com/products.php?product_id=1112]]
  * Adafruit FadeCandy - Dithering USB-Controlled Driver for NeoPixels [[https://www.adafruit.com/product/1689]]
  * 3 x Adafruit NeoPixel Ring - 16 x WS2812 5050 RGB LED with Integrated Drivers [[https://www.adafruit.com/products/1463]]
  * Adafruit Adafruit NeoPixel Digital RGBW LED Strip - Black PCB 144 LED/m - 1m [[https://www.adafruit.com/products/2848]]
  * Adafruit Flora RGB Smart NeoPixel version 2 - Pack of 4 [[https://www.adafruit.com/products/1260]]
  * White 3.5mm Microphone Earphone Socket USB 2.0 Sound Card Speaker Audio Adapter for Raspberry Pi 2

====== Light concept ======
For the visual feedback we developed a light concept which integrates several LEDs: single LEDs for the background illumination of the buttons, LED rings around the three buttons on the front side and an LED strip inside the handle. All LEDs we used are Adafruit's so-called NeoPixels which can show all RGB-colors and are individually controllable.

{{:root:2015:pimu:20160218_221043.jpg?200|}}

The light concept is depending on the different states of the player:
  * is ready (after boot, nothing is playing at the moment, waiting for a token to be attached): all buttons are yellow, the rings are off
  * is playing (after a token has been attached): the play/pause button is green as well as the ring around it, the next and previous buttons and the rings around them are blue, the recording button stays yellow
  * is paused: the play/pause button switches to red, the rest stays the same
  * pressing next/previous: the next resp. previous button turns violet while being pressed to go to the next/previous song and pink while being pressed and held to wind forwards/backwards, the rest stays the same
  * is ready for recording (after the recording-token has been attached): the recording button turns green, the rest stays as it was
  * is recording (after the recording button has been pressed): the recording button turns red, the rest stays the same
The LED strip is always mapped to the current volume setting: the louder the pinker, the quieter the greener.