Knock Sensor Circuit Design ...

[tandy ass]

Hence me wanting to know further information

[doctor ed]

ok

built the circuit, and the sucker works
hehehe

BUT at the moment, it takes a HEFTY whack with a ballpein hammer on the deck of the block (on the cyl above where the sensor is mounted) to get the thing to trigger.

i have no idea how powerful a shock detonation puts through the block, but i suspect at the moment the circuit isnt sensitive enough, so im going to swap the 1N914 diode (0.571v forward bias) for a germanium diode (lower forward bias volatge) and hopefully capture things at a lower threshold (0.45v or so?)

i might put the two diodes on a rotary switch so i flip between the two as i figure how this thing works.

anyway, its looking 'not bad' as a basic indicator of what the sensor is hearing...

cheers
ed