Shaft rotation monitor for seed drill

Hi there,

I’m new to these IoT IDEs and am looking to build a monitor for a shaft on my agricultural seed drill. Not sure if Arduino is the right choice? Are the projects hardy enough once housed in the tractor cab to cope with vibration duct etc?

The problem I am trying to solve is that sometimes due to a mechanical issue, the shaft drive that causes the seed to come out of the seeder, fails to engage. If the operator does not catch the problem by looking at a visual indicator on the shaft, then a portion of the paddock does not get sown, and you do not find out until the crop germinates:(

For the alarm to be useful, it should only alarm when the seed drill is lowered into the ground and the seed drill is moving. A reed switch can detect the drill being in-ground, and we need some sort of movement detector function to detect motion, once those conditions are met then a second reed switch and a time delay relay could be used to only activate/ alarm if the reed switch does not pulse within the relay delay time.

Hi Bob,

It may be possible to implement this using a microcontroller (doesn’t necessarily have to be an Arduino board) although you’re exactly right, with all the vibration, dust, and I’d imagine heat, the system likely won’t have too long a lifetime, there’s huge investment from mining and agricultural machine manufacturers into protecting electronics properly to extend their lifetime and even then failures still occur occasionally.

Can you send us some photos of your drill and ideas if possible? I’m not sure that you’d need a microcontroller at all to set that up as it seems like this is just a logic problem. You may be able to get away with using some relays, a piezo or similar buzzer, a power supply, and the reed switches rather than needing to detect each condition on a microcontroller than determine whether or not the drill is down.

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The device you are referring to is known as a watchdog timer. It is a timer that needs a ‘kick’ at regular intervals, or it sounds an alarm. There is an example here that is being used to check that an Arduino is still alive and active. In your case the ‘kick’ or heartbeat would come from a sensor such as a reed relay or a hall-effect sensor that was triggered as the shaft rotated, and the output would be to a relay that switched a lamp or buzzer. The rotation of the shaft gives the timer the required kick, but if it doesn’t occur within a predetermined time the timer times out and the alarm is raised. The whole thing would be switched by a similar sensor that detected whether the seed drill was lowered or not. If you also wanted to turn the device off when the seeder was lowered but not turning, that would probably be best addressed with a manual switch.

An Arduino or similar would certainly work, but is overkilll for that solution. The required electronics are simple enough to be safely housed in a padded box. Reliability problems are more likely to be associated with the sensors and the wiring back to the cab.

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