Parachute Deployment Timer
I am busy trying to build a parachute deployment timer for an amateur rocket using 555 ics
What have I done thus far
I have a switch that closes temporarily while the rocket accelerates. I am trying to use a Bistable 555 to latch the acceleration switch and a "delay before on" 555 to drive a MOSFET which will sink current for a piece of nichrome wire.
Basically I am trying to combine the two circuits shown below
delay before on 555
I have "breadboarded" both of these circuits individually using LEDs to test the output and they both did what they were supposed to do. When I try combining the two circuits things go skew.
Below is schematic of what I am trying to do with the two 555. my problems begin at Q1 and M1
So here are my questions
1. How do I use transistor Q1 to ground the reset pin of U2 or is there an easier way to place Q1 so as to stop U2 from starting the delay sequence?
2. How do I drive a power MOSFET with the output U2