Finding a Tilt Switch for Your Bike Alarm

[Gughanath]

I have a circuit that I am going to use as a bike alarm. The problem is that I will need a tilt switch which acts like a push-to-break switch ...is it possible to get a switch like that? ...or are there any alternatives?please reply...

 

[NoTime]

The simplest switch I have seen is a ball bearing in a shallow metal dish with a second conductive ring around it. The depth of the dish sets the maximum allowable tilt.
in the case of a parked bike there would probably be enough tilt to trigger it while movement would cause the ball to break contact with the ring.
You could make one or perhaps an auto parts store.
You could also use an XY accelerometer IC. These are sensitive to orientation.
Try google for sources of various commercial switches.

 

[Cliff_J]

Mercury switches? No moving parts then and cheap too.

 

[Gughanath]

it seems impossible to find a Momentary tilt switch (if it exists). Does a Momentary Vibration sensor exist at all? I desperately need one :(

 

[Gughanath]

The simplest switch I have seen is a ball bearing in a shallow metal dish with a second conductive ring around it. The depth of the dish sets the maximum allowable tilt.
in the case of a parked bike there would probably be enough tilt to trigger it while movement would cause the ball to break contact with the ring.
You could make one or perhaps an auto parts store.
You could also use an XY accelerometer IC. These are sensitive to orientation.
Try google for sources of various commercial switches.

is the ball bearing switch a momentary one?

 

[NoTime]

is the ball bearing switch a momentary one?

What do you mean by momentary?
All switches are to some degree momentary.

You say this is an alarm system.
Most alarm systems simply ignore the activation sensor state (switch on or off) once triggered.

 

[Gughanath]

For the circuit to work, the tilt switch needs to return to its normal position, which is the off position.If the switch doesn't return to the off position, the automatic reset system in the circuit will not work.

 

[NoTime]

Yes. The auto reset feature would be a problem.

To some degree the ball bearing idea will still work here,
since there would only be a small angle over which it would fail to reset.

For high reliability the accelerometer IC and a micro computer chip would probably be required.