Help..! I'm a pretty novice mech guy getting my hands into this dark art, so please excuse my fairly basic knowledge / ignorance......
I have 4 individual 12 vdc signals coming from some NPN output proximity sensors. These 4 sensors form a "set" that I want to signal a single channel of my logger with. In order to record a sensor "event" I only need around a half second pulse to capture the event.
My first challenge is to merge the 4 sensor signals into one output then the second is to convert each sensing event (which could be several minutes) into a single short pulse.
The critical thing is that whilst one sensor may be active, I still need any of the other three to be able to signal an event (to the same logger input)
The current required for the logger channel is very small (less than 100mA) so I am hoping an transistor solution is workable. I cannot use mechanical relays due to speed, reliability and noise issues.
I have tried using a 555 timer, but it needs to be powered separately and only seems to trigger to ground, not by the application of the 12v line. They also need matched caps and pull up/down resistors and finish up having to build them onto a board.... I have 20 sets of these to complete.
Does anyone have any ideas of a simple circuit to do do this? I need it to be as simple a solution as possible.
I have 4 individual 12 vdc signals coming from some NPN output proximity sensors. These 4 sensors form a "set" that I want to signal a single channel of my logger with. In order to record a sensor "event" I only need around a half second pulse to capture the event.
My first challenge is to merge the 4 sensor signals into one output then the second is to convert each sensing event (which could be several minutes) into a single short pulse.
The critical thing is that whilst one sensor may be active, I still need any of the other three to be able to signal an event (to the same logger input)
The current required for the logger channel is very small (less than 100mA) so I am hoping an transistor solution is workable. I cannot use mechanical relays due to speed, reliability and noise issues.
I have tried using a 555 timer, but it needs to be powered separately and only seems to trigger to ground, not by the application of the 12v line. They also need matched caps and pull up/down resistors and finish up having to build them onto a board.... I have 20 sets of these to complete.
Does anyone have any ideas of a simple circuit to do do this? I need it to be as simple a solution as possible.