Installed my bin sensor today. Works fine with a manual test, but time will tell how well it does measuring actual dust levels in the bin.
I bought the Banner QS18VN6D from China via Bhiner. Two versions were available depending on cord length: a 12 inch cord at US$10.60 or a standard length cord (6 ft?) at US$15.95. I chose the short cord. With all fees and shipping came to US$31.98.
The strobe is the one linked by Ben from e-bay, US$3.37 delivered. The power supply is this one
http://www.banggood.com/Wholesale-WW...r-p-62956.html
at CDN$6.46 (approx. US$4.75). I wanted a 240v input rated corded power supply so I could cut the input plug off and wire it directly to the 240v motor output of the magnetic starter. That way the power supply is powered only when the DC is running, a feature I wanted.
I mounted the strobe on the lid of a Hammond 1591GSBK box CDN$5.93 (approx US$4.50) and installed a DC power jack and a cable gland in the box side to receive the cable from the MOLEX connector I used at the sensor. Connectors, cable, and washers to mount the sensor came to CDN$12.50 (approx US$9.25).
All in, about US$54.00. If it works well with actual dust levels, I will be happy. I've had to clean filters, etc. a couple of times from overfull bins, and that did not make me happy!