Rotation detection sensor with schematics

[selva prabhu]

Hi All,
I need to know the mechanical sensor or other sensor which can detect the rotation of chain.
When the rotation of chain stopped it should trigger alarm using 24v buzzer.
Kindly help me to over come this circuit.

 

[jpanhalt]

Presumably the chain runs over sprockets. One relatively common method is to use a Hall sensor mounted across the sprocket teeth to detect movement. You can also put a magnet anywhere else on the sprocket or shaft and detect its rotation. Similar applications have been used in cars for many years now. Check out ABS braking system. They are also used in small gasoline engines (e.g., model airplane engines) to control timing. There is lots of information about both applications on the Internet.

John

 

[MaxHeadRoom78]

There are also hall effect sensors that do not require magnets but detect gear teeth, as used in automobiles now for timing.
But smaller ones are available
Max.

 

[KeepItSimpleStupid]

The general circuit is a "missing pulse detector" or "frequency switch". See this https://www.mtl-inst.com/images/uploads/datasheets/8000/io_modules/22/8123.pdf for a commercial module that does a lot more.

The sensor isn't a hall effect sensor, but rater a variable reluctance sensor. https://en.wikipedia.org/wiki/Variable_reluctance_sensor

 

[gophert]

Various motor encoders are available - you can attach one to the drive shaft, the driven shaft or add an idler shaft. Various designs of motor encoders but all essentially put out a pulse or quadrature pulse (allows detection of forward or reverse direction).