You need below stuffs:
1. A HEXBUG nano
You need the HEXBUG nano. I recommend the one which has clear window on the top.
2. SMD Transistor
I have tried 2SC4116 and 2SC3325. 2SC3325 is better because it has bigger body and larger collector current.http://akizukidenshi.com/catalog/g/gI-00628/
3. Photo diode
I used PS1101W.http://akizukidenshi.com/catalog/g/gI-01674/
4. A design knife
You need it to uncover the bug.
5. A screw driver (+)
You need it to remove battery cover.
6. Soldering iron and solders
You need them to build the circuit.
7. A tweezer
The parts is very small. You need it.
8. A mini knipper
You need it to cut off the wire of the toggle switch.
9. A double sided tape
You may need it to hold parts when you solder them.
10. A instant glue
You need it to bond the bug's cover and body.