How to design a circuit that detects when motor is jammed?

[david90]

help with circuit

I have a 555 timer in monostable mode. When the 555's output is active, it drives a transistor which drive a dpdt relay which drive a motor.

I need to know how to make a circuit that can detect when motor the stop because of a jam. Since the 555 has a reset pin, a circuit that sends a logic 1 to the reset pin when the motor jam would be nice.

 

[david90]

help with circuit

one thing, the 555 timing function is already been used by the other part of my circuit so I can't use that for the circuit above.

 

[aamir]

Re: help with circuit

Which type of motor u r using :?:

 

[solvarg]

Re: help with circuit

I have a 555 timer in monostable mode. When the 555's output is active, it drives a transistor which drive a dpdt relay which drive a motor.

I need to know how to make a circuit that can detect when motor the stop because of a jam. Since the 555 has a reset pin, a circuit that sends a logic 1 to the reset pin when the motor jam would be nice.

If it is an DC motor,
Putt a resistor (low ohm) in series of the motor, measure the voltage across the resistor with an OP-amp. Connect OP-amp as an comparator an set to desired trip level. Feed output from comparator to 555 reset pin. When the motor is jamed, a higher current is going trough the resistor and creates a higher voltage dropp detected by the comparator.

Please give detailes on motor.

Regards