latch circuit design

[ffuzz]

hi,

i am trying to design a circuit that will latch for x ms (somewhere between 30-100ms) whenever input voltage is above x mV (around 5) ...

the input of the circuit is a piezoelectric transducer to detect vibration
the output of this circuit will be triggering, and hopefully latching a relay that will turn household current on.

the end result of the project will be a lighting system triggered by drums. i have found designs to amplify and filter the input somewhat, however the signal still tries to fire the relay too fast.

im not sure if this is even the right forum for such a question, but if anyone has suggestions for designing such a latch (if it is even called a latch), please let me know. im am quite inexperienced in circuit design.

thanks a bunch.

-ffuzz

 

[elec_lover]

A small ac signal can be amplified with opamps. after the last opamp connect an integrator > n pulses received => DC is incrementing in condenser > level trigger if you need a shard pulse

 

[k7elp60]

latching circuit

You could use a comparator to monitor the input voltage. When the voltage equals or exceeds the input the comparator could drive a one-shot MV adjusted to your latch time. The one-shot could easily drive a relay to turn on the AC voltage.