I'm working on a hobby project and bought some cheap linear actuators with motors in them. Due to the terrible motor speed/torque, I switched them out. Now I have to implement a safety feature to kill the power to the motor whenever a limit switch is actuated in the device. (It tears up the device if it goes too far.)
Below is the project setup, but this is what I think i need to do. I need to a N-channel power MOSFET to control a P-channel MOSFET. The first one can be this one and will control a 12v current from the power supply to trigger a second MOSFET. This second one is what will kill the power to the motor whenever a voltage is applied. I think i need to use two because the voltage difference between the arduino and the 12vdc power supply is too much to trigger the P-channel MOSFET by itself quickly enough.
How off am I? I'm a hobbyist, but i'm trying to design it right before building it.
- Arduino board
- 12vdc brushed motor that normally pulls 15-20 amps
- H-Bridge Relay from Arduino to motor, for control, but not safety shutoff. http://www.vexrobotics.com/217-0220.html
- 12vdc power supply
- Linear actuator with gearing and two limit switches at either end of gear. (If either one is hit, then it breaks the circuit. setup in series.) Example actuator that looks similar but isn't.
To make it clear: This is a safety shutoff and will only be used to protect the motor from destroying the actuator if there is a bug in the program actuating the device. I can flip the power manually if the power gets cut because of this new circuit. I just can't rebuild the gearing.