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To all the electronic nerds out there: I am trying to trigger a 555 timer by movement in a random direction that also occurs randomly and any change in position should trigger the 555. AFAIK tilt switches are not useable here. Does this idea make sense?
Ferrite core In orange, spool in blue.
Would there be a voltage generated by movement if the core is suspended by some kind of spring or rubber band?
The idea being to play a sound from a df mini player by pulling a pin high for 3 seconds.
No, moving a ferrite core through a coil won't generate a voltage. You would need to move a magnet to generate a voltage.
Look for a vibration switch like one of these. If you want more control, you could use an accelerometer and a microcontroller to trigger it from a specific amount of movement.
I haven't done a course in electromagnetism yet, but as far as I understand, the ferrite core is just a piece of metal with no magnetic field, so moving it doesn't induce a voltage
I think it would, however, change the inductance, just like the iron core in a transformer does
No, that won't work.
A vibration switch will work.
If that's not sensitive enough, another option is using a piezo element coupled to the case to detect vibration, with an op-amp or hex inverter to buffer + trigger the 555. However if you couple it too closely with e.g. the floor or furniture it will pick up nearby footsteps or cars. Might be good depending on the situation.
If your coil was oscillating, then perhaps an iron core moving through it would cause perturbations which are detectable. But that would require extra logic to compare the expected oscillation frequency with what the coil is actually oscillating at.
Since you say that tilt switches are not an option -- for reasons I'm not entirely sure I understand -- another option is to have a linear Hall effect sensor mounted nearby a small magnet. If the magnet moves relative to the sensor, then that is a change which can be acted upon. A linear sensor makes it possible to use a trim pot to tune the sensitivity.
thanks for the reply
i failed to mention the most important aspect of the project: (near) zero power consumption when idle.
it is a vacuum (that kinda looks like r2d2) that i want to play some r2d2 noises when used.
it is hauled around on a construction site on the scaffolding and wont be in an upright position while idle or in usage, so tilt switches didnt make sense to me.
i plan to run it from a coincell or maybe 2 aa, but it should only draw power when the sensor is triggered so the power should last years if i understood the 555 timer correctly. that means accelerometers and linear hall effect sensors are out too due to microcontrollers and thus power draw.
somebody else mentioned vibration sensors (SW-18010) that look promising.
my spool idea was just bad ... :)