Hello fellow engineers!
I have a question for you guys.
I'm building a little project for a friend, it involves operating a latching solenoid from a low voltage signal. I'm sensing a voltage signal which ranges from about 0.5v to 1.3v, when the voltage gets up to about 0.7v i need to send a short pulse of about 1.5v 0.44A to the solenoid. When the signal voltage reaches about 0.8v i need to send another pulse (same specs) to the solenoid.
What i'm doing now. I am amplifying the signal from .7v/.8v to about 3.5v/4v using ina122 (inst. amp) [this step is still in theory since i haven't bought the amp yet hopefully it will work]. I then use quad comparator (2 of them) lm324 to compare the voltage which will send one signal when voltage is 3.5v and another when voltage is 4v.
This is where my question comes in, based on those two signals i need a rising edge trigger circuit for 2 signals which will send two separate pulses to the H-bridge which connects to the solenoid. I tried using the attached circuit but it doesn't work (yes i know it uses falling edge, just testing it) , when Vin changes from high to low, trigger voltage X changes only about 200mV, not enough to trigger 555. I also just read that the 555 timer cannot give me enough current (about .44A) to get the solenoid going. How do i get a pulse on the rising edge of my signal juicy enough to power my solenoid?
Any suggestions or comments are very appreciated!!
I have a question for you guys.
I'm building a little project for a friend, it involves operating a latching solenoid from a low voltage signal. I'm sensing a voltage signal which ranges from about 0.5v to 1.3v, when the voltage gets up to about 0.7v i need to send a short pulse of about 1.5v 0.44A to the solenoid. When the signal voltage reaches about 0.8v i need to send another pulse (same specs) to the solenoid.
What i'm doing now. I am amplifying the signal from .7v/.8v to about 3.5v/4v using ina122 (inst. amp) [this step is still in theory since i haven't bought the amp yet hopefully it will work]. I then use quad comparator (2 of them) lm324 to compare the voltage which will send one signal when voltage is 3.5v and another when voltage is 4v.
This is where my question comes in, based on those two signals i need a rising edge trigger circuit for 2 signals which will send two separate pulses to the H-bridge which connects to the solenoid. I tried using the attached circuit but it doesn't work (yes i know it uses falling edge, just testing it) , when Vin changes from high to low, trigger voltage X changes only about 200mV, not enough to trigger 555. I also just read that the 555 timer cannot give me enough current (about .44A) to get the solenoid going. How do i get a pulse on the rising edge of my signal juicy enough to power my solenoid?
Any suggestions or comments are very appreciated!!
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