Dillon/DAA Case Loader Sensor on a 550B

I just installed the DAA case loader on my Dillon 550B but knew I might not catch the tube being empty so I wanted a sensor to tell me when it was running low.

This uses a 12V Heschen M30 Inductive Proximity Sensor Switch I got on Amazon;
https://www.amazon.com/gp/product/B081NNN98M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I found that brass is less sensitive than iron so, after trial and error, I found I needed the 15mm distance found only on a 30mm diameter sensor.

For a 12VDC power supply, I used a ALITOVE DC 12V 5A Power Supply Adapter Converter Transformer, Amazon;
https://www.amazon.com/gp/product/B01GEA8PQA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
but any 12VDC source will work.

You also need an alert device, a 12V light or Buzzer will work. I used a DIGITEN AC DC 12V 22mm Red LED Flash Alarm 80dB Indicator Light Lamp with Buzzer, Amazon;
https://www.amazon.com/gp/product/B017YL31OY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

A switch is op