iRobot Roomba virtual wall DIY

This is a virtual wall design for a Roomba vacuum robot. I did not want to spend 70€ for two IR beacons - so I searched Thingiverse and found two designs:
https://www.thingiverse.com/thing:2687981 and
https://www.thingiverse.com/thing:51372

Those two designs where my base and I designed a virtual wall housing and used a simple Arduino code for the beacon signal.

The tower and cover have no holes - you have to drill them for your components.

I added the fritzing project and the arduino code.

Enjoy making!

The wall has a very wide angle so place it about half a meter away from the actual "no go line".

EDIT - Parts I used:
- Arduino pro mini - 5V, 16MHz
- DC jack (screwmount)
- 5mm IR LED lieing around
- 5mm LED holder
- BC547 NPN transistor
- 2k2 Ohm resistor for the transistor (Arduino pin 3 -> base)
- ??? Ohm resistor for the IR LED
- 3mm/5V LED green (powerindicator)
- toggle switch (switch between 9V battery and DC jack -> 7-16VDC RAW pin of Arduino)
- 9