These days, driving a tractor is no easy task. With the amount of technology jam packed into them, it can get a little distracting. This gets even worse when nightfall strikes and you can barely see outside. One thing that I noticed when I was spreading fertilizer on the farm is that at night time I was constantly stopping and getting out to check if I was out of fertilizer yet. On our new spreader it came with a viewing window so you could see in the hopper, which works great, except for at night. The light shines off, and there is virtually no light in the hopper, so your stuck looking at a black piece of glass. It is for these reasons why I decided to make a simple sensor that would warn me when I ran out. I used a potentiometerin the back to tell the height of the fertilizer coming out. Once it dropped past a certain point I had an alarm go off in the cab. This was achieved by using an Arduino to monitor the potentiometer, and turned on a buzzer and light when it dropped below acceptable levels.