try this link, I know they make the moisture sensor monitor on the JD balers and have many other products. Could find something. We have the all runs blockage sensors on our 1820, man is that sweet. I think it was like $6000 option, expensive, but sure handy, tells me right away if there's a plugged run. From what I've been told by my NH tech, the JD sensors are way, way better than the Flexi-Coil/CNH sensors on their drill, I think they have the optical eye, which gets dirty with small amounts of dust. Have to whip out a tooth brush to clean them, sure sounds like fun! Good luck.

http://www.farmtronics.com/ - checked their site, can't find anything.

Edit: http://www.dickey-john.com/pressroom/detail.php?news_id=3 - google search

Also saw Agtron ads in the Western Producer: http://www.agtron.com/artblock.html

http://www.loupelectronics.com/products/blockage_sensor.html - googled & found this, this may be the best one, seems like the same system as the Deere drills offer.

Also found that Vansco makes a optical system, might as well include it in the list! http://www.vansco.ca/products_sensors.php - interstingly enough, the founder of this company was born & raised about 10 miles south of where I live, I don't know him, but know other members of his family... I believe they are the ones that made all of the electronic clusters for the Versatile plant in Winnipeg & also supplied the Genesis lines as well, maybe others as well.

This should give you a few ideas to choose from!