Sensor that detects when metal sieve is clogged with debris
I would tackle this not from the point of view of the filter, but from the point of view of the water itself.
The water will be impeded by the filter. As the filter gradually clogs that impediment will increase.  The net result will be a slower flow of water through your filter.
There's a number of things you could do to detect that:

Measure the incoming water flow rate and the outgoing water flow rate and calculate the difference.

This would mean having all the water flowing through two flow meters which would complicate your design as the filter will no longer be able to deposit directly into the tank. But when the difference in flow between the in and out sensors gets above a certain point (to be determined by you) then you can safely say that the filter is blocked.

Measure the &quot;backlog&quot; of water. To do this the input portion of the filter will have to be sealed (or largely sealed). Again the filter will impede water flow, and the more it's clogged the more it impedes. Once the impediment becomes too high the water will start &quot;backing up&quot; up the input pipe as it can't get through the filter fast enough. At this time you can detect that rise in water level with a float switch.

You'd have a simpler design now, as the filter can deposit straight into the tank. Whether you want to detect the rise in water level in the incoming pipe itself or in the gap between the filter and where the pipe comes in depends largely on the size of your filter. With a large filter it may be better to have a smaller space at the top and measure in the pipe. That will &quot;amplify&quot; the level rise and make it easier to detect.