Quantity   Component name
1 × SI-3BG or other geiger tube capable of 600V Can detect beta, gamma, and x-ray. Will not be able to detect alpha or proton radiation.
1 × 2N2222 Transistor
1 × Audio device with 3.5mm jack You can use a plain speaker in place of the adapter but it won't be very loud
1 × 3.5mm jack adapter
1 × Switch
1 × Disposable Camera Flash Circuit Must be modified to be permanently on and not have the bulk storage capacitor
1 × Casing I used a printer power supply that I salvaged. You can use anything, just be sure to ground the case if it is made of a conductor.