A friend (who like to stay off the net) suggested a kinetic knife. It's about a knife that has to come close but it can't touch. (The idea comes from the books/movies "Dune" where they have kinetic shields).
After working on it for a while I have now managed to get everything together and working. Did some minor changes but over all it works better than expected.
From the top - component list
* Lance from the $$ store
* Long breadboard
* 2xAAA battery holder (inside the handle)
* on/off switch
* DC-DC Booster to convert 2.4V to 5V
* Arduino Pro 5V 328 16MHz
* 2x74HC595 shift register
* 1xULN2803 driver
* 5 RGB LEDs
* 4x7SEG display, Common Cathod
* Buzzer to make some noise
* 9x66.5 ohm resistors (58-100 probably works fine)
* 1x10K ohm resistor
* 5x330ohm resistor
* tcrt5000 sensor
* some wires
The Schematic for it, the battery and dc-dc is missing and using common anode RGB LEDs could been better (use driver IC instead of shift register) but now i had common cathode ones at home so that's what I used:
The code contains interrupt timer controlled driver for the digits using SPI to send it to the shift registers, just load an array with the numbers you want to display and forget about it. I'm happy with the way that part of the code worked out and will probably use it else were if I need it some other time.
The rest is just some logic to count points and make the RGB LEDs flash.
Version - 0.5 of the code