Gear wheel Fault detection

[guruparan.eee]

I am trying to do a circuit which detects the missing tooth from a gear wheel and gives a output if the tooth is missing using a magnetic transducer ?

anyone help me please

 

[crutschow]

Does the gear rotate at at one constant speed?

 

[guruparan.eee]

no it needs to bee working at any speed and any number of tooth

 

[MikeMl]

One way would be to use a phase locked loop locked to the normal tooth frequency. That would generate a clock edge that could be used to sample the missing tooth... You could do this in software inside a uController, too, i.e. compare the previous period between the two last teeth to a running average period.

 

[guruparan.eee]

One way would be to use a phase locked loop locked to the normal tooth frequency. That would generate a clock edge that could be used to sample the missing tooth... You could do this in software inside a uController, too, i.e. compare the previous period between the two last teeth to a running average period.

could you plese tell me what components i could use??

 

[MikeMl]

could you plese tell me what components i could use??

Which method, the PLL or uController?

 

[crutschow]

One way would be to use a phase locked loop locked to the normal tooth frequency. That would generate a clock edge that could be used to sample the missing tooth... You could do this in software inside a uController, too, i.e. compare the previous period between the two last teeth to a running average period.

It would seem to be difficult to get a phase locked loop to lock in over "any speed".

The uController approach seems more feasible.

 

[MikeMl]

Assuming some reasonable range of speeds, like an automobile engine (say 500rpm to 10000 rpm), a PLL would work fine.

 

[shortbus=]

Why not do it simply? Use a 555 timer to make a missing pulse detector, like this one; Missing Pulse Detector

Use a crank position sensor from a car engine to give the pulses from the gear; Crankshaft position sensor - Wikipedia, the free encyclopedia This is what a crank position sensor is made to do, sense a missing tooth on a gear wheel.

 

[crutschow]

Why not do it simply? Use a 555 timer to make a missing pulse detector, like this one; Missing Pulse Detector

Such a missing pulse detector will only work for a fixed frequency, since the 555 time must be set to be slightly longer than the period between pulses. It won't work for a range of speeds as the OP desires.

 

[misterT]

Use two magnetic transducers so that when the gear is ok their output is identical. If one tooth is missing then at some point the output of the sensors will be different.